1.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
2.
Body of water
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A body of water or waterbody is any significant accumulation of water, generally on a planets surface. The term most often refers to oceans, seas, and lakes, a body of water does not have to be still or contained, Rivers, streams, canals, and other geographical features where water moves from one place to another are also considered bodies of water. Most are naturally occurring geographical features, but some are artificial, there are types that can be either. For example, most reservoirs are created by engineering dams, similarly, most harbors are naturally occurring bays, but some harbors have been created through construction. Bodies of water that are navigable are known as waterways, some bodies of water collect and move water, such as rivers and streams, and others primarily hold water, such as lakes and oceans. The term body of water can also refer to a reservoir of water held by a plant, note that there are some geographical features involving water that are not bodies of water, for example waterfalls, geysers and rapids. Arm of the sea - also sea arm, used to describe a sea loch, arroyo - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, or seasonally. Artificial lake or artificial pond - see reservoir or impoundment, barachois - a lagoon separated from the ocean by a sand bar. Bay - an area of water bordered by land on three sides, similar to, but smaller than a gulf, bayou - a slow-moving stream or a marshy lake. Bight - a large and often only slightly receding bay, or a bend in any geographical feature, billabong - see Oxbow lake, a pond or still body of water created when a river changes course and some water becomes trapped. Boil - see Seep Brook - a small stream, canal - an artificial waterway, usually connected to existing lakes, rivers, or oceans. Channel - the physical confine of a river, slough or ocean consisting of a bed. See also stream bed and strait, earth scientists generally use the term to describe a circular or round inlet with a narrow entrance, though colloquially the term is sometimes used to describe any sheltered bay. Basin - a region of land where water from rain or snowmelt drains downhill into another body of water, such as a river, lake, creek - an inlet of the sea, narrower than a cove. Delta - the location where a river flows into an ocean, sea, estuary, lake, distributary or distributary channel - a stream that branches off and flows away from a main stream channel. Draw - a usually dry creek bed or gulch that temporarily fills with water after a heavy rain, fjord - a submergent landform which has occurred due to glacial activity. Glacier - a large collection of ice or a river that moves slowly down a mountain. Glacial Pothole - see Kettle Gulf - a part of a lake or ocean that extends so that it is surrounded by land on three sides, similar to, but larger than a bay, headland - an area of water bordered by land on three sides
3.
Sea
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A sea is a large body of salt water that is surrounded in whole or in part by land. More broadly, the sea is the system of Earths salty. The sea moderates Earths climate and has important roles in the cycle, carbon cycle. Although the sea has been traveled and explored since prehistory, the scientific study of the sea—oceanography—dates broadly to the British Challenger expedition of the 1870s. Owing to the present state of continental drift, the Northern Hemisphere is now equally divided between land and sea but the South is overwhelmingly oceanic. Salinity in the ocean is generally in a narrow band around 3. 5% by mass, although this can vary in more landlocked waters, near the mouths of large rivers. About 85% of the solids in the sea are sodium chloride. Deep-sea currents are produced by differences in salinity and temperature, surface currents are formed by the friction of waves produced by the wind and by tides, the changes in local sea level produced by the gravity of the Moon and Sun. The direction of all of these is governed by surface and submarine land masses, former changes in sea levels have left continental shelves, shallow areas in the sea close to land. The most diverse areas surround great tropical coral reefs, whaling in the deep sea was once common but whales dwindling numbers prompted international conservation efforts and finally a moratorium on most commercial hunting. Life may have started there and aquatic microbial mats are generally credited with the oxygenation of Earths atmosphere, the sea is an essential aspect of human trade, travel, mineral extraction, and power generation. It is the scene of activities including swimming, diving, surfing. However, population growth, industrialization, and intensive farming have all contributed to marine pollution. Atmospheric carbon dioxide is being absorbed in increasing amounts, lowering its pH in a known as ocean acidification. The shared nature of the sea has made overfishing an increasing problem, both senses of sea date to Old English, the larger sense has required a definite article since Early Middle English. Seas are generally larger than lakes and contain salt water, while the defining elements of size and being bounded are generally used, there is no formally accepted technical definition of sea among oceanographers. In international law, the United Nations Convention on the Law of the Sea states that all the ocean is the sea. Earth is the known planet with seas of liquid water on its surface, although Mars possesses ice caps
4.
Drainage basin
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A drainage basin or catchment area is any area of land where precipitation collects and drains off into a common outlet, such as into a river, bay, or other body of water. Drainage basins connect into other drainage basins at elevations in a hierarchical pattern, with smaller sub-drainage basins. Other terms used to describe drainage basins are catchment, catchment basin, drainage area, river basin and water basin. In closed drainage basins the water converges to a point inside the basin, known as a sink, which may be a permanent lake. The drainage basin acts as a funnel by collecting all the water within the covered by the basin. Each drainage basin is separated topographically from adjacent basins by a perimeter, drainage basins are similar but not identical to hydrologic units, which are drainage areas delineated so as to nest into a multi-level hierarchical drainage system. Hydrologic units are defined to allow multiple inlets, outlets, or sinks, in a strict sense, all drainage basins are hydrologic units but not all hydrologic units are drainage basins. Drainage basins of the oceans and seas of the world. Grey areas are endorheic basins that do not drain to the oceans, the following is a list of the major ocean basins, About 48. 7% of the worlds land drains to the Atlantic Ocean. The two major mediterranean seas of the world also flow to the Atlantic, The Caribbean Sea and Gulf of Mexico basin includes most of the U. S. The Mediterranean Sea basin includes much of North Africa, east-central Africa, Southern, Central, and Eastern Europe, Turkey, and the areas of Israel, Lebanon. Just over 13% of the land in the world drains to the Pacific Ocean, the Indian Oceans drainage basin also comprises about 13% of Earths land. It drains the eastern coast of Africa, the coasts of the Red Sea and the Persian Gulf, the Indian subcontinent, Burma, antarctica comprises approximately eight percent of the Earths land. The five largest river basins, from largest to smallest, are the basins of the Amazon, the Río de la Plata, the Congo, the Nile, and the Mississippi. The three rivers that drain the most water, from most to least, are the Amazon, Ganga, endorheic drainage basins are inland basins that do not drain to an ocean. Around 18% of all land drains to endorheic lakes or seas or sinks, the largest of these consists of much of the interior of Asia, which drains into the Caspian Sea, the Aral Sea, and numerous smaller lakes. Some of these, such as the Great Basin, are not single drainage basins but collections of separate, in endorheic bodies of standing water where evaporation is the primary means of water loss, the water is typically more saline than the oceans. An extreme example of this is the Dead Sea, drainage basins have been historically important for determining territorial boundaries, particularly in regions where trade by water has been important
5.
India
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India, officially the Republic of India, is a country in South Asia. It is the seventh-largest country by area, the second-most populous country, and it is bounded by the Indian Ocean on the south, the Arabian Sea on the southwest, and the Bay of Bengal on the southeast. It shares land borders with Pakistan to the west, China, Nepal, and Bhutan to the northeast, in the Indian Ocean, India is in the vicinity of Sri Lanka and the Maldives. Indias Andaman and Nicobar Islands share a border with Thailand. The Indian subcontinent was home to the urban Indus Valley Civilisation of the 3rd millennium BCE, in the following millennium, the oldest scriptures associated with Hinduism began to be composed. Social stratification, based on caste, emerged in the first millennium BCE, early political consolidations took place under the Maurya and Gupta empires, the later peninsular Middle Kingdoms influenced cultures as far as southeast Asia. In the medieval era, Judaism, Zoroastrianism, Christianity, and Islam arrived, much of the north fell to the Delhi sultanate, the south was united under the Vijayanagara Empire. The economy expanded in the 17th century in the Mughal empire, in the mid-18th century, the subcontinent came under British East India Company rule, and in the mid-19th under British crown rule. A nationalist movement emerged in the late 19th century, which later, under Mahatma Gandhi, was noted for nonviolent resistance, in 2015, the Indian economy was the worlds seventh largest by nominal GDP and third largest by purchasing power parity. Following market-based economic reforms in 1991, India became one of the major economies and is considered a newly industrialised country. However, it continues to face the challenges of poverty, corruption, malnutrition, a nuclear weapons state and regional power, it has the third largest standing army in the world and ranks sixth in military expenditure among nations. India is a constitutional republic governed under a parliamentary system. It is a pluralistic, multilingual and multi-ethnic society and is home to a diversity of wildlife in a variety of protected habitats. The name India is derived from Indus, which originates from the Old Persian word Hindu, the latter term stems from the Sanskrit word Sindhu, which was the historical local appellation for the Indus River. The ancient Greeks referred to the Indians as Indoi, which translates as The people of the Indus, the geographical term Bharat, which is recognised by the Constitution of India as an official name for the country, is used by many Indian languages in its variations. Scholars believe it to be named after the Vedic tribe of Bharatas in the second millennium B. C. E and it is also traditionally associated with the rule of the legendary emperor Bharata. Gaṇarājya is the Sanskrit/Hindi term for republic dating back to the ancient times, hindustan is a Persian name for India dating back to the 3rd century B. C. E. It was introduced into India by the Mughals and widely used since then and its meaning varied, referring to a region that encompassed northern India and Pakistan or India in its entirety
6.
Myanmar
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Myanmar, officially the Republic of the Union of Myanmar and also known as Burma, is a sovereign state in South East Asia bordered by Bangladesh, India, China, Laos and Thailand. About one third of Myanmars total perimeter of 5,876 km, forms an uninterrupted coastline of 1,930 km along the Bay of Bengal, the countrys 2014 census revealed a much lower population than expected, with 51 million people recorded. Myanmar is 676,578 square kilometres in size and its capital city is Naypyidaw and its largest city and former capital city is Yangon. Early civilizations in Myanmar included the Tibeto-Burman-speaking Pyu city-states in Upper Burma, the Pagan Kingdom fell due to the Mongol invasions and several warring states emerged. In the 16th century, reunified by the Taungoo Dynasty, the country was for a period the largest empire in the history of Mainland Southeast Asia. The early 19th century Konbaung Dynasty ruled over an area included modern Myanmar and briefly controlled Manipur. The British invaded Myanmar after three Anglo-Burmese Wars in the 19th century and the became a British colony. Myanmar became an independent nation in 1948, initially as a nation and then, following a coup détat in 1962. For most of its independent years, the country has been engrossed in rampant ethnic strife, during this time, the United Nations and several other organisations have reported consistent and systematic human rights violations in the country. In 2011, the junta was officially dissolved following a 2010 general election. While former military leaders still wield enormous power in the country, there is, however, continuing criticism of the governments treatment of the Muslim Rohingya minority and its poor response to the religious clashes. In the landmark 2015 election, Aung San Suu Kyis party won a majority in both houses, Myanmar is a country rich in jade and gems, oil, natural gas and other mineral resources. In 2013, its GDP stood at US$56.7 billion, the income gap in Myanmar is among the widest in the world, as a large proportion of the economy is controlled by supporters of the former military government. As of 2016, according to the Human Development Index, Myanmar had a level of human development. The renaming remains a contested issue, many political and ethnic opposition groups and countries continue to use Burma because they do not recognise the legitimacy of the ruling military government or its authority to rename the country. The countrys official name is the Republic of the Union of Myanmar. Countries that do not officially recognise that name use the long form Union of Burma instead, in English, the country is popularly known as either Burma or Myanmar /ˈmjɑːnˌmɑːr/. Both these names are derived from the name of the majority Burmese Bamar ethnic group, Myanmar is considered to be the literary form of the name of the group, while Burma is derived from Bamar, the colloquial form of the groups name
7.
Thailand
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Thailand, officially the Kingdom of Thailand, formerly known as Siam, is a country at the centre of the Indochinese peninsula in Southeast Asia. With a total area of approximately 513,000 km2, Thailand is the worlds 51st-largest country and it is the 20th-most-populous country in the world, with around 66 million people. The capital and largest city is Bangkok, Thailand is a constitutional monarchy and has switched between parliamentary democracy and military junta for decades, the latest coup being in May 2014 by the National Council for Peace and Order. Its capital and most populous city is Bangkok and its maritime boundaries include Vietnam in the Gulf of Thailand to the southeast, and Indonesia and India on the Andaman Sea to the southwest. The Thai economy is the worlds 20th largest by GDP at PPP and it became a newly industrialised country and a major exporter in the 1990s. Manufacturing, agriculture, and tourism are leading sectors of the economy and it is considered a middle power in the region and around the world. The country has always been called Mueang Thai by its citizens, by outsiders prior to 1949, it was usually known by the exonym Siam. The word Siam has been identified with the Sanskrit Śyāma, the names Shan and A-hom seem to be variants of the same word. The word Śyâma is possibly not its origin, but a learned, another theory is the name derives from Chinese, Ayutthaya emerged as a dominant centre in the late fourteenth century. The Chinese called this region Xian, which the Portuguese converted into Siam, the signature of King Mongkut reads SPPM Mongkut King of the Siamese, giving the name Siam official status until 24 June 1939 when it was changed to Thailand. Thailand was renamed Siam from 1945 to 11 May 1949, after which it reverted to Thailand. According to George Cœdès, the word Thai means free man in the Thai language, ratcha Anachak Thai means kingdom of Thailand or kingdom of Thai. Etymologically, its components are, ratcha, -ana- -chak, the Thai National Anthem, written by Luang Saranupraphan during the extremely patriotic 1930s, refers to the Thai nation as, prathet Thai. The first line of the anthem is, prathet thai ruam lueat nuea chat chuea thai, Thailand is the unity of Thai flesh. There is evidence of habitation in Thailand that has been dated at 40,000 years before the present. Similar to other regions in Southeast Asia, Thailand was heavily influenced by the culture and religions of India, Thailand in its earliest days was under the rule of the Khmer Empire, which had strong Hindu roots, and the influence among Thais remains even today. Voretzsch believes that Buddhism must have been flowing into Siam from India in the time of the Indian Emperor Ashoka of the Maurya Empire, later Thailand was influenced by the south Indian Pallava dynasty and north Indian Gupta Empire. The Menam Basin was originally populated by the Mons, and the location of Dvaravati in the 7th century, the History of the Yuan mentions an embassy from the kingdom of Sukhothai in 1282
8.
Indonesia
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Indonesia, officially the Republic of Indonesia, is a unitary sovereign state and transcontinental country located mainly in Southeast Asia with some territories in Oceania. Situated between the Indian and Pacific oceans, it is the worlds largest island country, with more than seventeen thousand islands. At 1,904,569 square kilometres, Indonesia is the worlds 14th-largest country in terms of area and worlds 7th-largest country in terms of combined sea. It has an population of over 260 million people and is the worlds fourth most populous country. The worlds most populous island, Java, contains more than half of the countrys population, Indonesias republican form of government includes an elected legislature and president. Indonesia has 34 provinces, of which five have Special Administrative status and its capital and countrys most populous city is Jakarta, which is also the most populous city in Southeast Asia and the second in Asia. The country shares land borders with Papua New Guinea, East Timor, other neighbouring countries include Singapore, Vietnam, the Philippines, Australia, Palau, and the Indian territory of the Andaman and Nicobar Islands. Despite its large population and densely populated regions, Indonesia has vast areas of wilderness that support the second highest level of biodiversity. The country has abundant natural resources like oil and natural gas, tin, copper, agriculture mainly produces rice, palm oil, tea, coffee, cacao, medicinal plants, spices and rubber. Indonesias major trading partners are Japan, United States, China, the Indonesian archipelago has been an important region for trade since at least the 7th century, when Srivijaya and then later Majapahit traded with China and India. Local rulers gradually absorbed foreign cultural, religious and political models from the early centuries CE, Indonesian history has been influenced by foreign powers drawn to its natural resources. Indonesia consists of hundreds of native ethnic and linguistic groups. The largest – and politically dominant – ethnic group are the Javanese, a shared identity has developed, defined by a national language, ethnic diversity, religious pluralism within a Muslim-majority population, and a history of colonialism and rebellion against it. Indonesias national motto, Bhinneka Tunggal Ika, articulates the diversity that shapes the country, Indonesias economy is the worlds 16th largest by nominal GDP and the 8th largest by GDP at PPP, the largest in Southeast Asia, and is considered an emerging market and newly industrialised country. Indonesia has been a member of the United Nations since 1950, Indonesia is a member of the G20 major economies and World Trade Organization. The name Indonesia derives from the Greek name of the Indós, the name dates to the 18th century, far predating the formation of independent Indonesia. In 1850, George Windsor Earl, an English ethnologist, proposed the terms Indunesians—and, his preference, in the same publication, one of his students, James Richardson Logan, used Indonesia as a synonym for Indian Archipelago. However, Dutch academics writing in East Indies publications were reluctant to use Indonesia, they preferred Malay Archipelago, the Netherlands East Indies, popularly Indië, the East, and Insulinde
9.
Malaysia
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Malaysia is a federal constitutional monarchy located in Southeast Asia. Peninsular Malaysia shares a land and maritime border with Thailand and maritime borders with Singapore, Vietnam, East Malaysia shares land and maritime borders with Brunei and Indonesia and a maritime border with the Philippines and Vietnam. The capital city is Kuala Lumpur, while Putrajaya is the seat of the federal government, with a population of over 30 million, Malaysia is the 44th most populous country. The southernmost point of continental Eurasia, Tanjung Piai, is in Malaysia, located in the tropics, Malaysia is one of 17 megadiverse countries on earth, with large numbers of endemic species. Malaysia has its origins in the Malay kingdoms present in the area which, from the 18th century, the first British territories were known as the Straits Settlements, whose establishment was followed by the Malay kingdoms becoming British protectorates. The territories on Peninsular Malaysia were first unified as the Malayan Union in 1946, Malaya was restructured as the Federation of Malaya in 1948, and achieved independence on 31 August 1957. Malaya united with North Borneo, Sarawak, and Singapore on 16 September 1963 to become Malaysia, less than two years later in 1965, Singapore was expelled from the federation. The country is multi-ethnic and multi-cultural, which plays a role in politics. About half the population is ethnically Malay, with minorities of Malaysian Chinese, Malaysian Indians. The constitution declares Islam the state religion while allowing freedom of religion for non-Muslims, the government system is closely modelled on the Westminster parliamentary system and the legal system is based on common law. The head of state is the king, known as the Yang di-Pertuan Agong and he is an elected monarch chosen from the hereditary rulers of the nine Malay states every five years. The head of government is the prime minister, since its independence, Malaysia has had one of the best economic records in Asia, with its GDP growing at an average of 6. 5% per annum for almost 50 years. The economy has traditionally been fuelled by its resources, but is expanding in the sectors of science, tourism, commerce. Today, Malaysia has a newly industrialised market economy, ranked third largest in Southeast Asia, the name Malaysia is a combination of the word Malay and the Latin-Greek suffix -sia/-σία. The word melayu in Malay may derive from the Tamil words malai and ur meaning mountain and city, land, malayadvipa was the word used by ancient Indian traders when referring to the Malay Peninsula. Whether or not it originated from these roots, the word melayu or mlayu may have used in early Malay/Javanese to mean to steadily accelerate or run. This term was applied to describe the current of the river Melayu in Sumatra. The name was adopted by the Melayu Kingdom that existed in the seventh century on Sumatra
10.
Indian Ocean
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The Indian Ocean is the third largest of the worlds oceanic divisions, covering 70,560,000 km2. It is bounded by Asia on the north, on the west by Africa, on the east by Australia, the Indian Ocean is known as Ratnākara, the mine of gems in ancient Sanskrit literature, and as Hind Mahāsāgar, in Hindi. The northernmost extent of the Indian Ocean is approximately 30° north in the Persian Gulf, the oceans continental shelves are narrow, averaging 200 kilometres in width. An exception is found off Australias western coast, where the width exceeds 1,000 kilometres. The average depth of the ocean is 3,890 m and its deepest point is Diamantina Deep in Diamantina Trench, at 8,047 m deep, Sunda Trench has a depth of 7, 258–7,725 m. North of 50° south latitude, 86% of the basin is covered by pelagic sediments. The remaining 14% is layered with terrigenous sediments, glacial outwash dominates the extreme southern latitudes. The major choke points include Bab el Mandeb, Strait of Hormuz, the Lombok Strait, the Strait of Malacca, the Indian Ocean is artificially connected to the Mediterranean Sea through the Suez Canal, which is accessible via the Red Sea. All of the Indian Ocean is in the Eastern Hemisphere and the centre of the Eastern Hemisphere is in this ocean, marginal seas, gulfs, bays and straits of the Indian Ocean include, The climate north of the equator is affected by a monsoon climate. Strong north-east winds blow from October until April, from May until October south, in the Arabian Sea the violent Monsoon brings rain to the Indian subcontinent. In the southern hemisphere, the winds are milder. When the monsoon winds change, cyclones sometimes strike the shores of the Arabian Sea, the Indian Ocean is the warmest ocean in the world. Long-term ocean temperature records show a rapid, continuous warming in the Indian Ocean, Indian Ocean warming is the largest among the tropical oceans, and about 3 times faster than the warming observed in the Pacific. Research indicates that human induced greenhouse warming, and changes in the frequency, among the few large rivers flowing into the Indian Ocean are the Zambezi, Shatt al-Arab, Indus, Godavari, Krishna, Narmada, Ganges, Brahmaputra, Jubba and Irrawaddy River. The oceans currents are controlled by the monsoon. Two large gyres, one in the northern hemisphere flowing clockwise and one south of the equator moving anticlockwise, during the winter monsoon, however, currents in the north are reversed. Deep water circulation is controlled primarily by inflows from the Atlantic Ocean, the Red Sea, north of 20° south latitude the minimum surface temperature is 22 °C, exceeding 28 °C to the east. Southward of 40° south latitude, temperatures drop quickly, surface water salinity ranges from 32 to 37 parts per 1000, the highest occurring in the Arabian Sea and in a belt between southern Africa and south-western Australia
11.
Bay of Bengal
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The Bay of Bengal, the largest bay in the world, forms the northeastern part of the Indian Ocean. Roughly triangular, it is bordered mostly by India and Sri Lanka to the west, Bangladesh to the north, and Myanmar, the Bay of Bengal occupies an area of 2,172,000 square kilometres. Among the important ports are Chennai, Chittagong, Colombo, Kolkata, Mongla, Paradip, Tuticorin, Visakhapatnam, on the south, Adams Bridge and from the southern extreme of Dondra Head to the north point of Poeloe Bras. The bay gets its name from the historical Bengal region, in ancient Hindu scriptures, this water body is referred to as Mahodadhi while it appears as Sinus Gangeticus or Gangeticus Sinus, meaning Gulf of the Ganges, in ancient maps. The other Sanskrit names for Bay of Bengal are Vangopasagara, also called as Vangasagara. Even today in Bengali, it is known as Bongoposagor, many major rivers of the Indian subcontinent flow west to east before draining into the Bay of Bengal. The Ganga is the northernmost of these and its main channel enters and flows through Bangladesh, where it is known as the Padma River, before joining the Meghna River. However, the Brahmaputra River flows from east to west in Assam before turning south and this joins the Padma whereupon the Padma joins the Meghna River that finally drains into Bay of Bengal. The Sundarbans mangrove forest at the delta of the Ganges, Brahmaputra and Meghna rivers lies partly in West Bengal, the Brahmaputra at 2,948 km is the 28th longest River in the world. The Hooghly River, another channel of the Ganga that flows through Calcutta drains into Bay of Bengal in India itself, the Ganga–Brahmaputra rivers deposits nearly 1000 million tons of sediment per year. The Bay of Bengal used to be deeper than the Mariana Trench, the fan has buried organic carbon at a rate of nearly 1.1 trillion mol/yr since the early Miocene period. The two rivers currently contribute nearly 8% of the organic carbon deposited in the worlds oceans. Due to high TOC accumulation in the sea bed of the Bay of Bengal. Bangladesh can reclaim land substantially and economically from the sea area by constructing sea dikes, bunds, causeways and by trapping the sediment from its rivers. Further south of Bengal, the Mahanadi, Godavari, Krishna and Kaveri Rivers are the rivers that flow from west to east in the Indian subcontinent. Many small rivers drain directly into the Bay of Bengal. The Irrawaddy River in Myanmar flows into the Andaman Sea of the Bay of Bengal, some of the biggest ports in the world — Chennai, Visakhapatnam, Paradip, Kolkata in India as well as Chittagong and Mongla in Bangladesh — are on the bay. Other Indian ports on the bay include Kakinada, Pondicherry, Dhamra, the islands in the bay are numerous, including the Andaman Islands, Nicobar and Mergui groups of India
12.
Andaman and Nicobar Islands
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The Andaman and Nicobar Islands, one of the seven union territories of India, are a group of islands at the juncture of the Bay of Bengal and Andaman Sea. The territory is 150 km north of Aceh in Indonesia and separated from Thailand and it comprises two island groups, the Andaman Islands and the Nicobar Islands, separated by the 10°N parallel, with the Andamans to the north of this latitude, and the Nicobars to the south. The Andaman Sea lies to the east and the Bay of Bengal to the west, the territorys capital is the Andamanese town of Port Blair. The total land area of islands is approximately 8,249 km2. The capital of Nicobar Islands is Car Nicobar, the islands host the Andaman and Nicobar Command, the only tri-service geographical command of the Indian Armed Forces. The Andaman Islands are home to the only known Paleolithic people, the Sentinelese people, the earliest archaeological evidence yet documented goes back some 2,200 years. Since that time, the Andamanese have diversified into distinct linguistic, the Nicobar Islands appear to have been populated by people of various backgrounds. At the time of the European contact, the inhabitants were the Nicobarese people, speaking a Mon-Khmer language. Both are unrelated to the Andamanese, but being closely related to the Myanmarese, rajendra Chola I, one of the Tamil Chola dynasty kings, conquered the Andaman and Nicobar Islands to use them as a strategic naval base to launch a naval expedition against the Sriwijaya Empire. The islands also provided a maritime base for ships of the Maratha Empire in the 17th century. The Maratha navys admiral Kanhoji Angre established naval supremacy with a base in the islands and is credited with attaching those islands to India. The history of organised European colonisation on the islands began when the Danish settlers of the Danish East India Company arrived in the Nicobar Islands on 12 December 1755. On 1 January 1756, the Nicobar Islands were made a Danish colony, first named New Denmark, during 1754–1756 they were administrated from Tranquebar. The islands were abandoned due to outbreaks of malaria between 14 April 1759 and 19 August 1768, from 1787 to 1807/05,1814 to 1831,1830 to 1834. From 1 June 1778 to 1784, Austria mistakenly assumed that Denmark had abandoned its claims to the Nicobar Islands and attempted to establish a colony on them, renaming them Theresia Islands. In 1789 the British set up a base and penal colony on Chatham Island next to Great Andaman. Two years later the colony was moved to Port Cornwallis on Great Andaman, denmarks presence in the territory ended formally on 16 October 1868 when it sold the rights to the Nicobar Islands to Britain, which made them part of British India in 1869. In 1858 the British again established a colony at Port Blair, the primary purpose was to set up a penal colony criminal convicts from the Indian subcontinent
13.
Malay Peninsula
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The Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southernmost point of the Asian mainland, the area contains the southernmost tip of Myanmar, Peninsular Malaysia, and Southern Thailand. The Titiwangsa Mountains are part of the Tenasserim Hills system, and they form the southernmost section of the central cordillera which runs from Tibet through the Kra Isthmus into the Malay Peninsula. The Strait of Malacca separates the Malay Peninsula from the Indonesian island of Sumatra while the south coast is separated from the island of Singapore by the Straits of Johor, the Malay term Tanah Melayu is derived from the word Tanah and Melayu, thus it means the Malay land. The term can be found in various pre-modern Malay texts, of which the oldest dating back to the early 17th century and it is frequently mentioned in the Hikayat Hang Tuah, a well known classical work that began as oral tales associated with the legendary heroes of Malacca Sultanate. Tanah Melayu in the text is consistently employed to refer to the area under Melakan dominance, prior to the foundation of Melaka, reference to Malay peninsula was made in different terms from various foreign sources. According to several Indian scholars, the word Malayadvipa, mentioned in the ancient Indian text, Vayu Purana, may possibly refer to the Malay peninsula. Another Indian source, an inscription on the wall of the Brihadeeswarar Temple, recorded the word Malaiur. The Greek source, Geographia, written by Ptolemy, labelled a geographical part of Golden Chersonese as Maleu-kolon, a term thought to derive from Sanskrit malayakolam or malaikurram. During the same era, Marco Polo made a reference to Malauir in his travelogue, as a kingdom located in the Malay peninsula, possibly similar to the one mentioned in Yuan chronicle
14.
Sumatra
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Sumatra is a large island in western Indonesia that is part of the Sunda Islands. It is the largest island that is entirely in Indonesia and the sixth-largest island in the world at 473,481 km2, Sumatra is an elongated landmass spanning a diagonal northwest-southeast axis. The Indian Ocean borders the west, northwest, and southwest sides of Sumatra with the chain of Simeulue, Nias. On the northeast side the narrow Strait of Malacca separates the island from the Malay Peninsula, on the southeast the narrow Sunda Strait separates Sumatra from Java. The northern tip of Sumatra borders the Andaman Islands, while on the eastern side are the islands of Bangka and Belitung, Karimata Strait. The Bukit Barisan mountains, which several active volcanoes, form the backbone of the island, while the northeast sides are outlying lowlands with swamps, mangrove. The equator crosses the island at its center on West Sumatra, the climate of the island is tropical, hot and humid with lush tropical rain forest once dominating the landscape. Sumatra was known in ancient times by the Sanskrit names of Swarnadwīpa and Swarnabhūmi, the first word mentioning the name of Sumatra was the name of Srivijayan Haji Sumatrabhumi, who sent an envoy to China in 1017. Arab geographers referred to the island as Lamri in the tenth through thirteenth centuries, late in the 14th century the name Sumatra became popular in reference to the kingdom of Samudra Pasai, which was a rising power until it was replaced by Sultanate of Aceh. Sultan Alauddin Shah of Aceh, on letters written in 1602 addressed to Queen Elizabeth I of England, referred to himself as king of Aceh, the word itself is from Sanskrit Samudra, meaning gathering together of waters, sea or ocean. European writers in the 19th century found that the inhabitants did not have a name for the island. The Melayu Kingdom was absorbed by Srivijaya, Srivijaya was a Buddhist monarchy centred in what is now Palembang. Dominating the region trade and conquest throughout the 7th to 9th centuries. The empire was a thalassocracy or maritime power that extended its influence from island to island, Palembang was a center for scholarly learning, and it was there the Chinese Buddhist pilgrim I Ching studied Sanskrit in 671 CE before departing for India. On his journey to China, he spent four years in Palembang translating Buddhist texts, Srivijayan influence waned in the 11th century after it was defeated by the Chola Empire of southern India. At the same time, Islam made its way to Sumatra through Arabs, by the late 13th century, the monarch of the Samudra kingdom had converted to Islam. Marco Polo visited the island in 1292, and Ibn Battuta visited twice during 1345–1346, Samudra was succeeded by the powerful Aceh Sultanate, which survived to the 20th century. With the coming of the Dutch, the many Sumatran princely states fell under their control
15.
Coral reef
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Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. Coral reefs are built by colonies of tiny animals found in waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups, the polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons which support, most reefs grow best in warm, shallow, clear, sunny and agitated waters. Often called rainforests of the sea, shallow coral reefs form some of the most diverse ecosystems on Earth, paradoxically, coral reefs flourish even though they are surrounded by ocean waters that provide few nutrients. They are most commonly found at depths in tropical waters. Coral reefs deliver ecosystem services to tourism, fisheries and shoreline protection, the annual global economic value of coral reefs is estimated between US$29. 8-375 billion. However, coral reefs are fragile ecosystems, partly because they are sensitive to water temperature. Most of the coral reefs we can see today were formed after the last glacial period when melting ice caused the sea level to rise and this means that most modern coral reefs are less than 10,000 years old. As communities established themselves on the shelves, the reefs grew upwards, Reefs that rose too slowly could become drowned reefs. They are covered by so much water there was insufficient light. Coral reefs are found in the sea away from continental shelves, around oceanic islands. The vast majority of islands are volcanic in origin. The few exceptions have tectonic origins where plate movements have lifted the deep ocean floor on the surface. In 1842 in his first monograph, The Structure and Distribution of Coral Reefs, Charles Darwin set out his theory of the formation of atoll reefs and he theorized uplift and subsidence of the Earths crust under the oceans formed the atolls. Darwin’s theory sets out a sequence of three stages in atoll formation and it starts with a fringing reef forming around an extinct volcanic island as the island and ocean floor subsides. As the subsidence continues, the reef becomes a barrier reef. Darwin predicted that underneath each lagoon would be a bed rock base, where the level of the underlying earth allows, the corals grow around the coast to form what he called fringing reefs, and can eventually grow out from the shore to become a barrier reef
16.
2004 Indian Ocean earthquake and tsunami
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The 2004 Indian Ocean earthquake occurred at 00,58,53 UTC on 26 December with the epicentre off the west coast of Sumatra, Indonesia. The shock had a moment magnitude of 9. 1–9.3 and it was one of the deadliest natural disasters in recorded history. Indonesia was the country, followed by Sri Lanka, India. It is the third-largest earthquake ever recorded on a seismograph and had the longest duration of faulting ever observed and it caused the entire planet to vibrate as much as 1 centimetre and triggered other earthquakes as far away as Alaska. Its epicentre was between Simeulue and mainland Indonesia, the plight of the affected people and countries prompted a worldwide humanitarian response. In all, the community donated more than US$14 billion in humanitarian aid. The event is known by the community as the Sumatra–Andaman earthquake. The resulting tsunami was given names, including the 2004 Indian Ocean tsunami, South Asian tsunami, Indonesian tsunami, the Christmas tsunami. The tsunami was initially documented as moment magnitude 8.8, in February 2005 scientists revised the estimate of the magnitude to 9.0. Although the Pacific Tsunami Warning Center has accepted these new numbers, the most recent studies in 2006 have obtained a magnitude of Mw 9. 1–9.3. Dr. Hiroo Kanamori of the California Institute of Technology believes that Mw 9.2 is a representative value for the size of this great earthquake. The hypocentre of the earthquake was approximately 160 km off the western coast of northern Sumatra. The northern section of the Sunda megathrust ruptured over a length of 1,300 km, the earthquake was felt in Bangladesh, India, Malaysia, Myanmar, Thailand, Singapore and the Maldives. Splay faults, or secondary pop up faults, caused long and this quickly elevated the height and increased the speed of waves, causing the complete destruction of the nearby Indonesian town of Lhoknga. Of all the seismic moment released by earthquakes in the 100 years from 1906 through 2005 and this quake, together with the Good Friday earthquake and the Great Chilean earthquake, account for almost half of the total moment. The much smaller but still catastrophic 1906 San Francisco earthquake is included in the diagram for perspective, Mw denotes the magnitude of an earthquake on the moment magnitude scale. Since 1900 the only recorded with a greater magnitude were the 1960 Great Chilean earthquake. The only other recorded earthquakes of magnitude 9.0 or greater were off Kamchatka, Russia, on 4 November 1952 and Tōhoku, each of these megathrust earthquakes also spawned tsunamis in the Pacific Ocean
17.
Strait of Malacca
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The Strait of Malacca or Straits of Malacca is a narrow,550 mi stretch of water between the Malay Peninsula and the Indonesian island of Sumatra. It is named after the Malacca sultanate that ruled over the archipelago between 1400 and 1511, the International Hydrographic Organization defines the limits of the Strait of Malacca as follows, On the West. A line joining Pedropunt, the Northernmost point of Sumatra and Lem Voalan the Southern extremity of Goh Puket in Siam, a line joining Tanjong Piai, the Southern extremity of the Malay Peninsula and The Brothers and thence to Klein Karimoen. The Southwestern coast of the Malay Peninsula, the Northeastern coast of Sumatra as far to the eastward as Tanjong Kedabu thence to Klein Karimoen. From an economic and strategic perspective, the Strait of Malacca is one of the most important shipping lanes in the world. The strait is the shipping channel between the Indian Ocean and the Pacific Ocean, linking major Asian economies such as India, China, Japan, Taiwan. Over 94,000 vessels pass through the strait each year, carrying about one-fourth of the traded goods, including oil, Chinese manufactured products. About a quarter of all oil carried by sea passes through the Strait, in 2007, an estimated 13.7 million barrels per day were transported through the strait, increasing to an estimated 15.2 million barrels per day in 2011. In addition, it is one of the worlds most congested shipping choke points because it narrows to only 2.8 km wide at the Phillips Channel. The maximum size of a vessel that can pass through the Strait is referred to as Malaccamax, for some of the worlds largest ships, the Straits minimum depth isnt deep enough. In addition, the next closest passageway is even more shallow and narrow than Malacca, therefore, these large ships must detour several thousand miles/kilometers and use the Lombok Strait, Makassar Strait, Sibutu Passage, or Mindoro Strait instead. Piracy has been a problem in the strait, piracy had been high in the 2000s, with additional increase after the events of September 11,2001. After attacks rose again in the first half of 2004, regional navies stepped up their patrols of the area in July 2004, subsequently, attacks on ships in the Strait of Malacca dropped, to 79 in 2005 and 50 in 2006. Recent reports indicate that attacks have dropped to levels in recent years. There are 34 shipwrecks, some dating to the 1880s, in the Traffic Separation Scheme and these pose a collision hazard in the narrow and shallow strait. Another risk is the annual haze due to raging bush fires in Sumatra and it may reduce visibility to 200 metres, forcing ships to slow down in the busy strait. The strait is used by Ships longer than 350 metres. Thailand has developed plans to diminish the economic significance of the strait
18.
International Hydrographic Organization
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The International Hydrographic Organization is the inter-governmental organisation representing hydrography. A principal aim of the IHO is to ensure that the seas, oceans. It does this through the setting of standards, the co-ordination of the endeavours of the worlds national hydrographic offices. The IHO enjoys observer status at the United Nations where it is the competent authority on hydrographic surveying. When referring to hydrography and nautical charting in Conventions and similar Instruments, it is the IHO standards, the IHO was established in 1921 as the International Hydrographic Bureau. The present name was adopted in 1970 as part of a new international Convention on the IHO adopted by the member nations. The former name International Hydrographic Bureau was retained to describe the IHO secretariat until 8 November 2016, there were substantial differences in hydrographic procedures charts, and publications. In 1889, an International Maritime Conference was held at Washington, D. C. similar proposals were made at the sessions of the International Congress of Navigation held at Saint Petersburg in 1908 and the International Maritime Conference held at Saint Petersburg in 1912. In 1919 the hydrographers of Great Britain and France cooperated in taking the steps to convene an international conference of hydrographers. London was selected as the most suitable place for this conference, and on 24 July 1919 and this is still the major purpose of the IHO. As a result of the conference, a permanent organization was formed, the IHB, now the IHO, began its activities in 1921 with 18 nations as members. The Principality of Monaco was selected as the seat of the organization as a result of the offer of Albert I, the IHO develops hydrographic and nautical charting standards. These standards are adopted and used by its 86 member countries and others in their surveys, nautical charts. Much has been done in the field of standardisation since the Bureau was founded, the IHO has encouraged the formation of Regional Hydrographic Commissions. Each RHC coordinates the national surveying and charting activities of countries within each region, the 15 RHCs plus the IHO Hydrographic Commission on Antarctica effectively cover the world. The IHO, in partnership with the Intergovernmental Oceanographic Commission, directs the General Bathymetric Chart of the Oceans programme, in 2010 the IHO introduced a new, contemporary hydrographic geospatial standard for modelling marine data and information, known as S-100. S-100 and any dependent product specifications are underpinned by an on-line registry accessible via the IHO website, S-100 is aligned with the ISO19100 series of geographic standards, thereby making it fully compatible with contemporary geospatial data standards. Because S-100 is based on ISO19100, it can be used by other providers for their maritime-related data
19.
Nicobar Islands
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The Nicobar Islands are an archipelagic island chain in the eastern Indian Ocean and one of the most isolated in the world. They are located in Southeast Asia,150 km north of Aceh on Sumatra, located 1,300 km southeast of the Indian subcontinent, across the Bay of Bengal, they form part of the Union Territory of Andaman and Nicobar Islands, India. UNESCO has declared the Great Nicobar Island as one of the World Network of Biosphere Reserves, the Nicobar Islands cover a land area of 1,648.13 km2 and had a population of 36,844 at the 2011 Census. The Nicobar Islands are part of an island arc created by the collision of the Indo-Australian Plate with Eurasia. The climate is warm and tropical, with temperatures ranging from 22 to 30 °C, rainfall is heavy due to annual monsoons and measures around 3000 to 3800 mm each year. The vegetation of the Nicobars is typically divided into the mangrove forests. Additionally, several islands contain extensive inland grasslands, though these are thought to result from human intervention, the Nicobar Islands are recognised as a distinct terrestrial ecoregion, the Nicobar Islands rain forests, with many endemic species. The Nicobar Islands are believed to have inhabited for thousands of years. An indigenous tribe living at the tip of Great Nicobar, called the Shompen. The modern name is derived from the Chola dynasty name for the islands. Marco Polo also referred to this island as Necuverann, the history of organised European colonisation on the islands began with the Danish East India Company in 1754/56. Between 1778 and 1783, William Bolts attempted to establish an Austrian colony on the islands on the assumption that Denmark–Norway had abandoned its claims to the islands. Italy made an attempt at buying the Nicobar Islands from Denmark between 1864 and 1868, the Italian Minister of Agriculture and Commerce Luigi Torelli started a negotiation that looked promising, but failed due to the unexpected end of his Office and the first La Marmora Cabinet. The negotiations were interrupted and never brought up again, denmarks presence in the islands ended formally on 16 October 1868 when it sold the rights to the Nicobar Islands to Britain, which in 1869 made them part of British India. During World War II, the islands were occupied by Japan between 1942 and 1945, India occupied the Island after that, as its Territory. Together with the Andaman Islands, they became a territory of India in 1950. On 26 December 2004, the coast of the Nicobar Islands was devastated by a 10–15 m high tsunami following the 2004 Indian Ocean earthquake. At least 6,000 people were killed on the Andaman, several islands were heavily damaged with initial reports of islands broken in two or three pieces and coral reefs moved above water
20.
Andaman Islands
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The Andaman Islands form an archipelago in the Bay of Bengal between India, to the west, and Myanmar, to the north and east. Most are part of the Andaman and Nicobar Islands Union Territory of India, while a number in the north of the archipelago, including the Coco Islands. The Andaman Islands are home to the Sentinelese, who have had no contact with any other people, the name of the Andaman Islands is ancient. A theory that became prevalent in the late 19th century is that it derives from Andoman, a form of Hanuman, another Italian traveller, Niccolò de Conti, mentioned the islands and said that the name means Island of Gold. The Andaman islands have been inhabited for several years, at the very least. The indigenous Andamanese people appear to have lived on the islands in substantial isolation from that time until the 18th century CE, from 800 to 1200 CE, the Tamil Chola dynasty created an empire that eventually extended from southeastern peninsular India to parts of Malaysia. Rajendra Chola I took over the Andaman and Nicobar Islands and maintained them as a naval base to launch a naval expedition against the Srivijaya empire. In 1789, Bengal Presidency established a base and penal colony on Chatham Island in the southeast bay of Great Andaman. The settlement is now known as Port Blair, after two years, the colony was moved to the northeast part of Great Andaman and was named Port Cornwallis after Admiral William Cornwallis. However, there was disease and death in the penal colony. In 1824, Port Cornwallis was the rendezvous of the carrying the army to the First Burmese War. In the 1830s and 1840s, shipwrecked crews who landed on the Andamans were often attacked and killed by the natives, in 1855, the government proposed another settlement on the islands, including a convict establishment, but the Indian Rebellion of 1857 forced a delay in its construction. However, because the rebellion gave the British so many prisoners, it made the new Andaman settlement and prison urgently necessary. Construction began in November 1857 at Port Blair using inmates labour,17 May 1859 was another major day for Andaman. The Battle of Aberdeen was fought between the Great Andamanese Tribe and the British, today, a memorial stands in Andaman Water sports complex as a tribute to the people who lost their life. Fearing foreign invasion and with help from a convict from Cellular Jail, the great Andamanese tribe stormed the British post. Later, it was identified that a convict named Doodnath had changed sides. Today, the tribe has been reduced to some 50 people, the government of Andaman Islands is making efforts to increase the headcount of this tribe
21.
Little Andaman
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Little Andaman Island is the fourth largest of the Andaman Islands of India with an area of 707 km², lying at the southern end of the archipelago. It belongs to the South Andaman administrative district, part of the Indian union territory of Andaman, the island is lying 88 km south from Port Blair, the capital of Andaman and Nicobar Islands and the nearest airport from where regular flights to Kolkata and Chennai are available. The island belongs to the Little Andaman Group, and is separated from Rutland Archipelago in Great Andaman by the Duncan Passage, Little Andaman Group is counterpart of the Great Andaman island group. The low-lying island has widespread rainforest and several species of marine turtle. Little Andaman Island has white sandy beaches and bewitching waterfalls, the Little Andaman Lighthouse is located 14 km south by road from Hut Bay port and is situated on the Southern tip of Little Andaman Island. Politically, Little Andaman Island is part of Little Andaman Tehsil, the island is home to the Onge aboriginal tribe, who call the island Egu Belong, and has been a tribal reserve since 1957. Settlers from erstwhile Bengal and other places also live here, as per the census of 2011, the population was 18,823 in 4,093 households, spread among 18 villages. The main village of Kwate-tu-Kwage is located on Hut Bay, Hut Bay wharf, a deep water wharf that can be approached through a gap in the coral reef, on the east coast of the island is the entry point of Little Andaman Island. Daily boat services connect Hut Bay wharf with Port Blair in ten hours voyage, additionally, there are a helicopter services by Pavan Hans Ltd. and a sea plane connection available between Port Blair and Hut Bay. The flight time by helicopter or sea plane is approximately 40 minutes, there is a road alongside the east coastal line and every village is named on the distance / km of the road by the residents. Little Andaman offers surfing, boating through the creeks, exciting elephant safari, elephant lumbering, Butler Bay,14 km from the Hut Bay Jetty, is a beautiful beach suitable for sun basking, coral viewing, surfing etc. Tourist huts are available on the seashore itself flanked by the coconut plantation, netaji Nagar Beach is 11 km from the Hut Bay Jetty. White Surf waterfall in the midst of the evergreen rainforest is 6.5 km from the Hut Bay Jetty, whisper Wave waterfall 25 km from the Hut Bay Jetty is also in the midst of the jungle. Journey to this waterfall includes 4 km trekking through the forest, from 4th km Crossing, you need to drive 800 m inside forest, where you will find a small waterfall that looks picturesque. The waterfall is 20–25 m high and there is a small bamboo grass all around, a government organisation, Andaman and Nicobar Islands Forest Plantation Development Corporation Limited, conducts package tour from Port Blair to the Little Andaman Island. It has more than 30 elephants on the Island and organises exciting elephant safari through the jungle near the White Surf waterfall, well-experienced and tamed elephants are engaged for this purpose. Elephant lumbering activities inside the forest and a camp where elephant calves are trained in lumbering activities can also be seen, ANIFPDCL has built a guest house and tourist huts on the beach. Boating facility is available in the creek near to the Butler Bay beach resort, the northern side of the Butler Bay beach is a popular surfing site
22.
Green algae
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The green algae are a large, informal grouping of algae consisting of the Chlorophyte and Charophyte algae, which are now placed in separate divisions. The land plants, or Embryophytes, are thought to have emerged from the Charophytes, therefore, cladistically, Embryophytes belong to green algae as well. However, as the Embryophytes are traditionally classified as neither algae nor green algae, the clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae and as the kingdom Plantae. The green algae include unicellular and colonial flagellates, most with two flagella per cell, as well as various colonial, coccoid and filamentous forms, and macroscopic, in the Charales, the closest relatives of higher plants, full cellular differentiation of tissues occurs. There are about 8,000 species of green algae, many species live most of their lives as single cells, while other species form coenobia, long filaments, or highly differentiated macroscopic seaweeds. A few other organisms rely on green algae to conduct photosynthesis for them, the chloroplasts in euglenids and chlorarachniophytes were acquired from ingested green algae, and in the latter retain a nucleomorph. Green algae are also found symbiotically in the ciliate Paramecium, and in Hydra viridissima, some species of green algae, particularly of genera Trebouxia of the class Trebouxiophyceae and Trentepohlia, can be found in symbiotic associations with fungi to form lichens. In general the species that partner in lichens cannot live on their own. Trentepohlia is a green alga that can live independently on humid soil. Green algae have chloroplasts that contain chlorophyll a and b, giving them a green color, as well as the accessory pigments beta carotene and xanthophylls. The cell walls of green algae usually contain cellulose, and they store carbohydrate in the form of starch, all green algae have mitochondria with flat cristae. When present, paired flagella are used to move the cell and they are anchored by a cross-shaped system of microtubules and fibrous strands. Flagella are only present in the male gametes of charophytes and are absent from the gametes of Pinophyta. Members of the class Chlorophyceae undergo closed mitosis in the most common form of division among the green algae. By contrast, charophyte green algae and land plants undergo open mitosis without centrioles, instead, a raft of microtubules, the phragmoplast, is formed from the mitotic spindle and cell division involves the use of this phragmoplast in the production of a cell plate. This primary endosymbiosis event gave rise to three autotrophic clades with primary plastids, the plants, the red algae and the glaucophytes. Green algae are classified with their embryophyte descendants in the green plant clade Viridiplantae. Viridiplantae, together with red algae and glaucophyte algae, form the supergroup Primoplantae, the Viridiplantae diverged into two clades
23.
Irrawaddy River
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The Irrawaddy River or Ayeyarwady River is a river that flows from north to south through Myanmar. It is the countrys largest river and most important commercial waterway, originating from the confluence of the Nmai and Mali rivers, it flows relatively straight North-South before emptying through the Irrawaddy Delta into the Andaman Sea. Its drainage basin of about 404,200 square kilometres covers a part of Burma. After Rudyard Kiplings poem, it is referred to as The Road to Mandalay. As early as the century the river was used for trade. Having developed a network of irrigation canals, the river became important to the British Empire after it had colonized Burma. The river is still as vital today, as an amount of goods. Rice is produced in the Irrawaddy Delta, irrigated by water from the river, environmental organisations have raised concerns about the ecological impacts on the rivers biodiverse ecosystems. Animals potentially impacted include the threatened Irrawaddy dolphin and the Irrawaddy river shark, the native Kachin people named the river Mali-Nmai-Hka. The Burmese name of Irrawaddy is derived from a Pali name for the Ravi River of India, airavati was the Pali version of the name of the elephant mount of Sakka, an important deva in Buddhism. Elephants were often a symbol for water and was used as the name for several others rivers, the Irrawaddy gives its name to the Irrawaddy dolphin, which is found in the lower reaches of the river and known to help fishermen who practice cast-net fishing. Though called Irrawaddy dolphin, it has also found in the Bay of Bengal. The Irrawaddy River bisects Myanmar from north to south and empties through the nine-armed Irrawaddy Delta into the Indian Ocean, the Irrawaddy River arises by the confluence of the Nmai and Mali Rivers in Kachin State. Both the Nmai and Mali Rivers find their sources in the Himalayan glaciers of Upper Burma near 28° N, the eastern branch of the two, Nmai, is the larger and rises in the Languela Glacier north of Putao. It is unnavigable because of the strong current whereas the western branch. Herefore, the Mali river is called by the same name as the main river by locals. The controversial Myitsone Dam is currently under construction at the convergence of these rivers, the city of Myitkyina lies 50 kilometres south of the confluence and can be reached during the dry season. Between Myitkyina and Mandalay, the Irrawaddy flows through three well-marked defiles, About 65 kilometres downstream from Myitkyinā is the first defile, below Bhamo the river makes a sharp westward swing, leaving the Bhamo alluvial basin to cut through the limestone rocks of the second defile
24.
Continental shelf
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The continental shelf is an underwater landmass which extends from a continent, resulting in an area of relatively shallow water known as a shelf sea. Much of the shelves were exposed during glacial periods and interglacial periods, the shelf surrounding an island is known as an insular shelf. The continental margin, between the shelf and the abyssal plain, comprises a steep continental slope followed by the flatter continental rise. Sediment from the continent above cascades down the slope and accumulates as a pile of sediment at the base of the slope, extending as far as 500 km from the slope, it consists of thick sediments deposited by turbidity currents from the shelf and slope. The continental rises gradient is intermediate between the slope and the shelf, on the order of 0. 5–1°, the largest shelf – the Siberian Shelf in the Arctic Ocean – stretches to 1,500 kilometers in width. The South China Sea lies over another extensive area of shelf, the Sunda Shelf, which joins Borneo, Sumatra. Other familiar bodies of water that overlie continental shelves are the North Sea, the average width of continental shelves is about 80 km. The depth of the shelf also varies, but is limited to water shallower than 150 m. The slope of the shelf is quite low, on the order of 0. 5°, vertical relief is also minimal. Though the continental shelf is treated as a province of the ocean, it is not part of the deep ocean basin proper. Passive continental margins such as most of the Atlantic coasts have wide and shallow shelves, active continental margins have narrow, relatively steep shelves, due to frequent earthquakes that move sediment to the deep sea. The shelf usually ends at a point of increasing slope, the sea floor below the break is the continental slope. Below the slope is the rise, which finally merges into the deep ocean floor. The continental shelf and the slope are part of the continental margin, the shelf area is commonly subdivided into the inner continental shelf, mid continental shelf, and outer continental shelf, each with their specific geomorphology and marine biology. The character of the shelf changes dramatically at the shelf break, with a few exceptions, the shelf break is located at a remarkably uniform depth of roughly 140 m, this is likely a hallmark of past ice ages, when sea level was lower than it is now. The continental slope is steeper than the shelf, the average angle is 3°. The slope is cut with submarine canyons. The physical mechanisms involved in forming these canyons were not well understood until the 1960s, the continental shelves are covered by terrigenous sediments, that is, those derived from erosion of the continents
25.
Isobath
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Bathymetry is the study of underwater depth of lake or ocean floors. In other words, bathymetry is the equivalent to hypsometry or topography. The name comes from Greek βαθύς, deep, and μέτρον, Bathymetric maps may also use a Digital Terrain Model and artificial illumination techniques to illustrate the depths being portrayed. The global bathymetry is combined with topography data to yield a Global Relief Model. Paleobathymetry is the study of past underwater depths, originally, bathymetry involved the measurement of ocean depth through depth sounding. Early techniques used pre-measured heavy rope or cable lowered over a ships side and this technique measures the depth only a singular point at a time, and is therefore inefficient. It is also subject to movements of the ship and currents moving the line out of true and therefore is inaccurate. The amount of time it takes for the sound or light to travel through the water, bounce off the seafloor, lIDAR/LADAR surveys are usually conducted by airborne systems. Starting in the early 1930s, single-beam sounders were used to make bathymetry maps, today, multibeam echosounders are typically used, which use hundreds of very narrow adjacent beams arranged in a fan-like swath of typically 90 to 170 degrees across. The tightly packed array of narrow individual beams provides very high angular resolution, in general a wide swath, which is depth dependent, allows a boat to map more seafloor in less time than a single-beam echosounder by making fewer passes. The beams update many times per second, allowing faster boat speed while maintaining 100% coverage of the seafloor, attitude sensors allow for the correction of the boats roll and pitch on the ocean surface, and a gyrocompass provides accurate heading information to correct for vessel yaw. A boat-mounted Global Positioning System positions the soundings with respect to the surface of the earth, sound speed profiles of the water column correct for refraction or ray-bending of the sound waves owing to non-uniform water column characteristics such as temperature, conductivity, and pressure. A computer system processes all the data, correcting for all of the factors as well as for the angle of each individual beam. The resulting sounding measurements are processed either manually, semi-automatically or automatically to produce a map of the area. As of 2010 a number of different outputs are generated, including a sub-set of the measurements that satisfy some conditions or integrated Digital Terrain Models. Historically, selection of measurements was more common in hydrographic applications while DTM construction was used for engineering surveys, geology, flow modeling, 2003–2005, DTMs have become more accepted in hydrographic practice. Satellites are also used to measure bathymetry, satellite radar maps deep-sea topography by detecting the subtle variations in sea level caused by the gravitational pull of undersea mountains, ridges, and other masses. On average, sea level is higher over mountains and ridges than over abyssal plains, coastal bathymetry data is available from NOAAs National Geophysical Data Center, which is now merged into National Centers for Environmental Information
26.
Silt
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Silt is granular material of a size between sand and clay, whose mineral origin is quartz and feldspar. Silt may occur as a soil or as sediment mixed in suspension with water in a body of such as a river. It may also exist as soil deposited at the bottom of a water body, Silt has a moderate specific area with a typically non-sticky, plastic feel. Silt usually has a floury feel when dry, and a slippery feel when wet, Silt can be visually observed with a hand lens. Silt is created by a variety of physical processes capable of splitting the generally sand-sized quartz crystals of primary rocks by exploiting deficiencies in their lattice and these involve chemical weathering of rock and regolith, and a number of physical weathering processes such as frost shattering and haloclasty. The main process is abrasion through transport, including fluvial comminution, aeolian attrition and it is in semi-arid environments that substantial quantities of silt are produced. Silt is sometimes known as rock flour or stone dust, especially produced by glacial action. Mineralogically, silt is composed mainly of quartz and feldspar, sedimentary rock composed mainly of silt is known as siltstone. Liquefaction created by an earthquake is silt suspended in water that is hydrodynamically forced up from below ground level. In the Udden–Wentworth scale, silt particles range between 0.0039 and 0.0625 mm, larger than clay but smaller than sand particles, ISO14688 grades silts between 0.002 mm and 0.063 mm. In actuality, silt is chemically distinct from clay, and unlike clay, grains of silt are approximately the size in all dimensions, furthermore. Clays are formed from thin plate-shaped particles held together by electrostatic forces, according to the U. S. Department of Agriculture Soil Texture Classification system, the sand-silt distinction is made at the 0.05 mm particle size. The USDA system has been adopted by the Food and Agriculture Organization, in the Unified Soil Classification System and the AASHTO Soil Classification system, the sand-silt distinction is made at the 0.075 mm particle size. Silts and clays are distinguished mechanically by their plasticity, Silt is easily transported in water or other liquid and is fine enough to be carried long distances by air in the form of dust. Thick deposits of silty material resulting from deposition by aeolian processes are called loess. Silt and clay contribute to turbidity in water, Silt is transported by streams or by water currents in the ocean. When silt appears as a pollutant in water the phenomenon is known as siltation, Silt, deposited by annual floods along the Nile River, created the rich, fertile soil that sustained the Ancient Egyptian civilization. In south east Bangladesh, in the Noakhali district, cross dams were built in the 1960s whereby silt gradually started forming new land called chars, the district of Noakhali has gained more than 28 square miles of land in the past 50 years
27.
Great Nicobar Island
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Great Nicobar is the southernmost and largest of the Nicobar Islands of India, north of Sumatra. Great Nicobar island was affected by the 2004 Indian Ocean earthquake tsunami with many deaths. The island of Sumatra is located 180 km to the south of Great Nicobar, the island covers 921 km2 but is sparsely inhabited, with a population of 8067, largely being covered by rainforest and known for its diverse wildlife. It is the southernmost air station of the Indian Armed Forces, the island is home to the Shompen people. The island has several rivers, including the Alexandra, Amrit Kaur, Dogmar, virtually all rivers flow in a southern or southwesterly direction, which is indicative of the general slope of the terrain across the island. There are undulating hills throughout the island, with the range running in a north-south orientation. Mount Thullier, which is part of range, has the highest elevation of any point in the Nicobars. Indira Point is the southernmost point of the Great Nicobar Island, Indira Point subsided 4.25 m in the 26 December 2004 tsunami and the lighthouse there was damaged. The lighthouse was made functional. There is a 915m airstrip at Campbell Bay/Tenlaa on the East coast, seaport, At least one small shipping dock is located in Campbell Bay. Indira Point is the name of the southernmost point of Republic of India and it is situated on Great Nicobar Island in the Nicobar Islands, which are located in the eastern Indian Ocean at 6°45’10″N and 93°49’36″E. This is not on the Indian mainland, but within the Union Territory of Andaman, the name of the point was changed from Pygmalion Point on 18 October 1985 in commemoration of Indira Gandhi. It was formerly known by names that include Pygmalion Point, Parsons Point. It is located 540 km and more than a sea voyage from Port Blair. It is approximately 150 km by sea from Sumatra, Indonesia, Indira Point has a 35 m high cast iron lighthouse with 16 nautical miles range. The lighthouse has with a 300 mm 4 panel revolving light inside a 2.5 m diameter lantern house and it is an important landmark on the international shipping lane Colombo-Singapore route via Malacca Strait that passes south of Indira Point. The tsunami which resulted from the Indian Ocean earthquake of 2004 inundated much of the area and this partly damaged the lighthouse, which subsided 4.25 m. As a result of subsidence, the coast retreated and the sea moved permanently inland
28.
Banda Aceh
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Banda Aceh, formerly known as Kutaradja, is the capital and largest city in the province of Aceh, Indonesia. It is located on the island of Sumatra and has an elevation of 35 meters, the city covers an area of 64 square kilometres and had a population of 219,070 people, according to the 2000 census. Banda Aceh is located on the tip of Indonesia at the mouth of the Aceh River. The city was established as Bandar Aceh Darussalam Kandang and served as a capital. Later its name was changed to Bandar Aceh Darussalam, and then became known as Banda Aceh. The first part of the name comes from the Persian bandar meaning port or haven, the city rose to international prominence in the aftermath of the Indian Ocean earthquake in 2004, which struck off the western coast of Sumatra. Banda Aceh was the closest major city to the earthquakes epicentre and it suffered great damage in the earthquake and further damage when a tsunami struck shortly afterwards. 167,000 people died as a result and many more were injured, Banda Aceh, situated at the tip of Sumatra, has long been a strategic, transportation and trading hub in the eastern Indian Ocean. Ibn Battuta also reported visiting the city in the century when under the control of the trading kingdom of Samudera Pasai. However the Pasai began to collapse under pressure from declining economic conditions and the Portuguese, after a long period of rule by the Sultanate, Aceh began to come into conflict with the Dutch and the British in the second half of the 18th century. At the end of the 18th century, the territory of Aceh in the Malay Peninsula, namely Kedah, in 1871, the Dutch began to threaten Aceh, and on 26 March 1873, the Dutch formally declared war on Aceh. The Dutch bombarded the capital in that year and sought to capture the Sultans palace in the city to bring about a capitulation of the Acehnese. Significant support from the British in the led the modernisation and fortification of the city. The Dutch expedition commander General Johan Köhler was killed in a skirmish around the city, a second expedition was mounted by the Dutch within months and was successful in overwhelming the city. On 26 December 2004, the city was hit by a tsunami caused by the 9. 2-magnitude earthquake in the Indian Ocean, the disaster killed 167,000 inhabitants and destroyed more than 60% of the citys buildings. Based on the statistical data issued by the City Government of Banda Aceh, Banda Aceh is divided into nine districts, One of the unique features of Banda Aceh are the motorised becaks that are found almost everywhere. Unlike traditional becaks, a motorised becak can take passengers anywhere in the city, the fare for riding a motorised becak is relatively cheap and is usually negotiated beforehand. Transport by taxis and minibuses, known as labi-labi, are also common, Sultan Iskandar Muda International Airport is located in Blang Bintang,13.5 km from Banda Aceh
29.
Plate tectonics
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The theoretical model builds on the concept of continental drift developed during the first few decades of the 20th century. The geoscientific community accepted plate-tectonic theory after seafloor spreading was validated in the late 1950s, the lithosphere, which is the rigid outermost shell of a planet, is broken up into tectonic plates. The Earths lithosphere is composed of seven or eight major plates, where the plates meet, their relative motion determines the type of boundary, convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along plate boundaries. The relative movement of the plates typically ranges from zero to 100 mm annually, tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle, the material lost is balanced by the formation of new crust along divergent margins by seafloor spreading. In this way, the surface of the lithosphere remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle, earlier theories, since disproven, proposed gradual shrinking or gradual expansion of the globe. Tectonic plates are able to move because the Earths lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the ridge and drag, with downward suction. Another explanation lies in the different forces generated by forces of the Sun. The relative importance of each of these factors and their relationship to other is unclear. The outer layers of the Earth are divided into the lithosphere and asthenosphere and this is based on differences in mechanical properties and in the method for the transfer of heat. Mechanically, the lithosphere is cooler and more rigid, while the asthenosphere is hotter, in terms of heat transfer, the lithosphere loses heat by conduction, whereas the asthenosphere also transfers heat by convection and has a nearly adiabatic temperature gradient. The key principle of plate tectonics is that the lithosphere exists as separate and distinct tectonic plates, Plate motions range up to a typical 10–40 mm/year, to about 160 mm/year. The driving mechanism behind this movement is described below, tectonic lithosphere plates consist of lithospheric mantle overlain by either or both of two types of crustal material, oceanic crust and continental crust. Average oceanic lithosphere is typically 100 km thick, its thickness is a function of its age, as passes, it conductively cools
30.
Burma Plate
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The Burma Plate is a minor tectonic plate or microplate located in Southeast Asia, sometimes considered a part of the larger Eurasian Plate. The Andaman Islands, Nicobar Islands, and northwestern Sumatra are located on the plate and this island arc separates the Andaman Sea from the main Indian Ocean to the west. To its east lies the Sunda Plate, from which it is separated along a transform boundary, to the west is the much larger India Plate, which is subducting beneath the eastern facet of the Burma Plate. This extensive subduction zone has formed the Sunda Trench, as the India Plate drifted northwards at a relatively rapid rate of an average 16 cm/yr, it also rotated in an counterclockwise direction. As a result of movement and rotation, the convergence along the plates eastern boundary with Eurasia was at an oblique angle. On December 26,2004, a portion of the boundary between the Burma Plate and the Indian Plate slipped, causing the 2004 Indian Ocean earthquake. This megathrust earthquake had a moment magnitude of 9. 1–9.3 Mw. Over 1600 km of the boundary underwent thrust faulting and shifted up to 5 meters vertically and 11 meters horizontally and this rapid rise in the sea floor over such a short time generated a massive tsunami that killed approximately 229,800 people along the coast of the Indian Ocean. Curray, JR.2002 Chapman Conference on Continent – Ocean Interactions within the East Asian Marginal Seas, tectonics and History of the Andaman Sea Region. Pdf Paul, J. Burgmann, R. Gaur, V. K. Bilham, R. Larson, K. M. Ananda, M. B. Jade, S. Mukal, M. Anupama, T. S. Satyal, G. Kumar, D.2001 The motion and active deformation of India
31.
Sunda Plate
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The Sunda Plate is a minor tectonic plate straddling the equator in the eastern hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, the Indo-Australian Plate dips beneath the Sunda Plate along the Sunda Trench, which generates frequent earthquakes. The eastern, southern, and western boundaries of the Sunda Plate are tectonically complex, only the northern boundary is relatively quiescent. Kutai basin List of earthquakes in Indonesia Sunda Arc Sunda Shelf Sunda Trench Bird, an updated digital model of plate boundaries, Geochemistry Geophysics Geosystems,4,1027, doi,10. 1029/2001GC000252. Also available as a PDF file
32.
Eurasian Plate
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It also includes oceanic crust extending westward to the Mid-Atlantic Ridge and northward to the Gakkel Ridge. The eastern side is a boundary with the North American Plate to the north and a boundary with the Philippine Sea Plate to the south, and possibly with the Okhotsk Plate and the Amurian Plate. The southerly side is a boundary with the African Plate to the west, the Arabian Plate in the middle, the westerly side is a divergent boundary with the North American Plate forming the northernmost part of the Mid-Atlantic Ridge, which is straddled by Iceland. The geodynamics of central Asia is dominated by the interaction between the Eurasian and Indian Plates, in this area, many subplates or crust blocks have been recognized, which form the Central Asian and the East Asian transit zones
33.
Transform fault
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A transform fault or transform boundary, is a type of fault whose relative motion is predominantly horizontal, in either a sinistral or dextral direction. Furthermore, transform faults end abruptly and are connected on both ends to other faults, ridges, or subduction zones, Transform faults are the only type of strike-slip fault that can be classified as a plate boundary. The new class of faults, called transform faults, produce slip in the direction from what one would surmise from the standard interpretation of an offset geological feature. Slip along transform faults does not increase the distance between the ridges it separates, the distance remains constant in earthquakes because the ridges are spreading centers. This hypothesis was confirmed in a study of the fault plane solutions that showed the slip on transform faults points in the opposite direction than classical interpretation would suggest, Transform faults are closely related to transcurrent faults, and are commonly confused. In addition, transform faults have equal deformation across the fault line, while transcurrent faults have greater displacement in the middle of the fault zone. Finally, transform faults can form a plate boundary, while transcurrent faults cannot. The effect of a fault is to strain, which can be caused by compression, extension. Transform faults specifically relieve strain by transporting the strain between ridges or subduction zones, Transform faults also act as the plane of weakness allowing for the splitting in rift zones. Transform faults are commonly found linking segments of mid-oceanic ridges or spreading centres and these mid-oceanic ridges are where new seafloor is constantly created through the upwelling of new basaltic magma. With new seafloor being pushed and pulled out, the older seafloor slowly slides away from the mid-oceanic ridges toward the continents, although separated only by tens of kilometers, this separation between segments of the ridges causes portions of the seafloor to push past each other in opposing directions. This lateral movement of seafloors past each other is where transform faults are currently active, Transform faults move differently than a strike-slip fault at the mid-oceanic ridge. Evidence of this can be found in paleomagnetic striping on the seafloor, a paper written by Gerya theorizes that the creation of the transform faults between the ridges of the mid-oceanic ridge is attributed to rotated and stretched sections of the mid-oceanic ridge. This occurs over a period of time with the spreading center or ridge slowly deforming from a straight line to a curved line. Finally, fracturing along these planes forms transform faults, as this takes place, the fault changes from a normal fault with extensional stress to a strike slip fault with lateral stress. In the study done by Bonatti & Crane, peridotite and gabbro rocks were discovered in the edges of the transform ridges and these rocks are created deep inside the Earth’s mantle and then rapidly exhumed to the surface. This evidence helps to prove that new seafloor is being created at the mid-oceanic ridges, as previously stated, active transform faults are between two tectonic structures or faults. Fracture zones represent the active transform fault lines, which have since passed the active transform zone and are being pushed toward the continents
34.
Indian Plate
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The Indian Plate or India Plate is a major tectonic plate straddling the equator in the eastern hemisphere. Originally a part of the ancient continent of Gondwana, India broke away from the fragments of Gondwana 100 million years ago. The Indian plate includes most of South Asia—i. e, until roughly 140 million years ago, the Indian Plate formed part of the supercontinent Gondwana together with modern Africa, Australia, Antarctica, and South America. Gondwana broke up as these continents drifted apart at different velocities, in the late Cretaceous, approximately 100 million years ago and subsequent to the splitting off from Gondwana of conjoined Madagascar and India, the Indian Plate split from Madagascar. It began moving north, at about 20 centimetres per year, however, some authors suggest that the collision between India and Eurasia occurred much later, around 35 million years ago. If the collision occurred between 55 and 50 Mya, the Indian Plate would have covered a distance of 3,000 to 2,000 kilometres, moving faster than any other known plate. These authors propose a continental fragment of northern Gondwana rifted from India, traveled northward and this was followed by the hard collision between India and Asia occurred at ~25 Ma. In 2007, German geologists suggested that the reason the Indian Plate moved so quickly is that it is half as thick as the other plates which formerly constituted Gondwana. The mantle plume that once broke up Gondwana might also have melted the part of the Indian subcontinent. The remains of this plume today form the Marion Hotspot, the Kerguelen hotspot, as India moved north, it is possible that the thickness of the Indian plate degenerated further as it passed over the hotspots and magmatic extrusions associated with the Deccan and Rajmahal Traps. The Indian Plate is currently moving north-east at 5 centimetres per year and this is causing the Eurasian Plate to deform, and the Indian Plate to compress at a rate of 4 millimetres per year. The westerly side of the Indian Plate is a boundary with the Arabian Plate called the Owen Fracture Zone. The northerly side of the Plate is a convergent boundary with the Eurasian Plate forming the Himalaya, List of tectonic plates List of tectonic plate interactions Paleogeography
35.
Continent
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A continent is one of several very large landmasses on Earth. Generally identified by convention rather than any strict criteria, up to seven regions are regarded as continents. Ordered from largest in size to smallest, they are, Asia, Africa, North America, South America, Antarctica, Europe, in geology, areas of continental crust include regions covered with water. Islands are frequently grouped with a continent to divide all the worlds land into geopolitical regions. Under this scheme, most of the countries and territories in the Pacific Ocean are grouped together with the continent of Australia to form a geopolitical region called Oceania. By convention, continents are understood to be large, continuous, discrete masses of land, many of the seven most commonly recognized continents identified by convention are not discrete landmasses separated completely by water. Earths major landmasses all have coasts on a single, continuous World Ocean, the most restricted meaning of continent is that of a continuous area of land or mainland, with the coastline and any land boundaries forming the edge of the continent. From this perspective the edge of the shelf is the true edge of the continent. In this sense the islands of Great Britain and Ireland are part of Europe, while Australia, as a cultural construct, the concept of a continent may go beyond the continental shelf to include oceanic islands and continental fragments. In this way, Iceland is considered part of Europe and Madagascar part of Africa, extrapolating the concept to its extreme, some geographers group the Australasian continental plate with other islands in the Pacific into one continent called Oceania. This divides the land surface of Earth into continents or quasi-continents. The ideal criterion that each continent be a discrete landmass is commonly relaxed due to historical conventions, of the seven most globally recognized continents, only Antarctica and Australia are completely separated from other continents by ocean. Several continents are defined not as absolutely distinct bodies but as more or less discrete masses of land, Asia and Africa are joined by the Isthmus of Suez, and North and South America by the Isthmus of Panama. In both cases, there is no separation of these landmasses by water. Both these isthmuses are very narrow compared to the bulk off the landmasses they unite, North America and South America are treated as separate continents in the seven-continent model. However, they may also be viewed as a continent known as America or the Americas. This viewpoint was common in the United States until World War II and this remains the more common vision in Latin American countries, Spain, Portugal, France, Italy and Greece, where they are taught as a single continent. The criterion of a landmass is completely disregarded if the continuous landmass of Eurasia is classified as two separate continents, Europe and Asia
36.
Back-arc basin
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Back-arc basins are geologic basins, submarine features associated with island arcs and subduction zones. They are found at convergent plate boundaries, presently concentrated in the western Pacific Ocean. Most of them result from tensional forces caused by oceanic trench rollback, the arc crust is under extension or rifting as a result of the sinking of the subducting slab. Back-arc basins were initially a surprising result for plate tectonics theorists, however, they are now recognized as consistent with this model in explaining how the interior of Earth loses heat. Back-arc basins are typically long and relatively narrow. The restricted width of back-arc basins is probably because magmatic activity depends on water and induced mantle convection, spreading rates vary from very slow spreading, a few centimeters per year, to very fast,15 cm/year. The high water contents of back-arc basin basalt magmas is derived from water carried down the subduction zone, additional source of water could be the eclogitization of amphiboles and micas in the subducting slab. Similar to mid-ocean ridges, back-arc basins have hydrothermal vents and associated chemosynthetic communities, back-arc basins are different from normal mid-ocean ridges because they are characterized by asymmetric seafloor spreading, but this is quite variable even within single basins. This situation is mirrored to the north where a large spreading asymmetry is also developed, the cause of asymmetric spreading in back-arc basins remains poorly understood. Back-arc basins are hypothesized to form as a result of trench rollback and this is the backward motion of the subduction zone relative to the motion of the plate which is being subducted. As the subduction zone and its associated trench pull backward, the plate is stretched. Sedimentation is strongly asymmetric, with most of the sediment supplied from the magmatic arc which regresses in step with the rollback of the trench. Active back-arc basins are found in the Marianas, Tonga-Kermadec, S. Scotia, Manus, N. Fiji, and Tyrrhenian Sea regions, not all subduction zones have back-arc basins, some like the central Andes are associated with rear-arc compression. In addition, there are a number of extinct or fossil back-arc basins, such as the Parece Vela-Shikoku Basin, Sea of Japan, the Black Sea formed from two separate back-arc basins. With the development of plate theory, geologists thought that convergent plate margins were zones of compression. The hypothesis that some convergent plate margins were actively spreading was developed by Dan Karig while a student at the Scripps Institution of Oceanography. This resulted from several marine geologic expeditions to the Western Pacific, back-arc region Forearc basin Intra-arc basin Uyeda S. Subduction zones, their diversity, mechanism and human impact
37.
Oceanic basin
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In hydrology, an oceanic basin may be anywhere on Earth that is covered by seawater, but geologically ocean basins are large geologic basins that are below sea level. Older references consider the oceanic basins to be the complement to the continents, with dominating the latter. Earth is the known planet in the solar system where hypsography is characterized by different kinds of crust, oceanic crust. Oceans cover 70% of the Earths surface, because oceans lie lower than continents, the former serve as sedimentary basins that collect sediment eroded from the continents, known as clastic sediments, as well as precipitation sediments. Ocean basins also serve as repositories for the skeletons of carbonate- and silica-secreting organisms such as reefs, diatoms, radiolarians. Geologically, a basin may be actively changing size or may be relatively, tectonically inactive. The elements of an active - and growing - oceanic basin include an elevated mid-ocean ridge, the elements of an active oceanic basin often include the oceanic trench associated with a subduction zone. The Atlantic ocean and the Arctic ocean are good examples of active, growing oceanic basins, the Pacific Ocean is also an active, shrinking oceanic basin, even though it has both spreading ridge and oceanic trenches. Perhaps the best example of an oceanic basin is the Gulf of Mexico. The Aleutian Basin is another example of an inactive oceanic basin. The Japan Basin in the Sea of Japan which formed in the Miocene, is still active although recent changes have been relatively mild. List of abyssal plains and oceanic basins List of oceanic landforms Solid Earth Wright, John et al
38.
Annum
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A year is the orbital period of the Earth moving in its orbit around the Sun. Due to the Earths axial tilt, the course of a year sees the passing of the seasons, marked by changes in weather, the hours of daylight, and, consequently, vegetation and soil fertility. In temperate and subpolar regions around the globe, four seasons are recognized, spring, summer, autumn. In tropical and subtropical regions several geographical sectors do not present defined seasons, but in the seasonal tropics, a calendar year is an approximation of the number of days of the Earths orbital period as counted in a given calendar. The Gregorian, or modern, calendar, presents its calendar year to be either a common year of 365 days or a year of 366 days, as do the Julian calendars. For the Gregorian calendar the average length of the year across the complete leap cycle of 400 years is 365.2425 days. The ISO standard ISO 80000-3, Annex C, supports the symbol a to represent a year of either 365 or 366 days, in English, the abbreviations y and yr are commonly used. In astronomy, the Julian year is a unit of time, it is defined as 365.25 days of exactly 86400 seconds, totalling exactly 31557600 seconds in the Julian astronomical year. The word year is used for periods loosely associated with, but not identical to, the calendar or astronomical year, such as the seasonal year, the fiscal year. Similarly, year can mean the period of any planet, for example. The term can also be used in reference to any long period or cycle, west Saxon ġēar, Anglian ġēr continues Proto-Germanic *jǣran. Cognates are German Jahr, Old High German jār, Old Norse ár and Gothic jer, all the descendants of the Proto-Indo-European noun *yeh₁rom year, season. Cognates also descended from the same Proto-Indo-European noun are Avestan yārǝ year, Greek ὥρα year, season, period of time, Old Church Slavonic jarŭ, Latin annus is from a PIE noun *h₂et-no-, which also yielded Gothic aþn year. Both *yeh₁-ro- and *h₂et-no- are based on verbal roots expressing movement, *h₁ey- and *h₂et- respectively, the Greek word for year, ἔτος, is cognate with Latin vetus old, from the PIE word *wetos- year, also preserved in this meaning in Sanskrit vat-sa- yearling and vat-sa-ras year. Derived from Latin annus are a number of English words, such as annual, annuity, anniversary, etc. per annum means each year, anno Domini means in the year of the Lord. No astronomical year has an number of days or lunar months. Financial and scientific calculations often use a 365-day calendar to simplify daily rates, in the Julian calendar, the average length of a year is 365.25 days. In a non-leap year, there are 365 days, in a year there are 366 days
39.
1797 Sumatra earthquake
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The 1797 Sumatra earthquake was the first in a series of great earthquakes that ruptured part of the Sumatran segment of the Sunda megathrust. It caused a tsunami that was particularly severe near Padang. The island of Sumatra lies on the convergent plate boundary between the Indo-Australian Plate and the Eurasian Plate, the major slip events on the subduction zone interface are typically of the megathrust type. Historically, great or giant megathrust earthquakes have been recorded in 1797,1833,1861,2004,2005 and 2007, smaller megathrust events have also occurred in the small gaps between the areas that slip during these larger events, in 1935,1984,2000 and 2002. The earthquake caused the collapse or damage of many houses, the tsunami surge drove an English sailing ship of 150–200 tons, moored in the Arau River, about 1 km inland, destroying several houses as it went. Smaller boats were driven up to 1.8 km upstream, in Air Manis, the whole town was flooded and the bodies of several people who had climbed trees to escape the surge were found the next day in the branches. Only two fatalities were reported from Padang itself but many more from Air Manis, the Batu Islands were also reported to be affected. The shaking at Padang lasted one minute, reports in 1845 and 1847 said either that this was the strongest earthquake in the memory of the residents of Padang or the strongest for forty years. The run-up of the tsunami at Padang and the village of Air Manis is estimated to be in the range of 5–10 m, modelling of tsunami effects using source parameters estimated from the uplift of coral microatolls, provide a reasonable match to the sparse historical records. The tsunami reports for this event are localised around Padang and it has suggested that the tsunami may have been caused by an underwater landslide triggered by the earthquake. List of earthquakes in Indonesia List of historical earthquakes List of historical tsunamis
40.
1833 Sumatra earthquake
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The 1833 Sumatra earthquake occurred on November 25 at about 22,00 local time, with an estimated magnitude in the range of 8. 8–9.2 Mw. It caused a tsunami that flooded the southwestern coast of the island. There are no records of the loss of life, with the casualties being described only as numerous. The magnitude of event has been estimated using records of uplift taken from coral microatolls. The island of Sumatra lies on the convergent plate boundary between the Indo-Australian Plate and the Eurasian Plate, the major slip events on the subduction zone interface are typically of megathrust type. Historically, great or giant megathrust earthquakes have been recorded in 1797,1833,1861,2004,2005 and 2007, smaller megathrust events have also occurred in the small gaps between the areas that slip during the larger events, in 1935,1984,2000 and 2002. There is only sparse information available regarding the extent of damage associated with either the earthquake or the subsequent tsunami, however, the tsunami was clearly devastating along the southwest coast of Sumatra from Pariaman to Bengkulu. There is also a report of significant damage in the Seychelles. The earthquake shaking lasted 5 minutes in Bengkulu and 3 minutes in Padang and these microatolls, named for their resemblance to island atolls, can be used to provide a record of sea level change. Microatolls form because the head cannot grow up beyond low tide level as exposure leads to death. The morphology of the microatolls directly reflects changes in HLS, the presence of annual growth banding combined with the Uranium-thorium dating method allows morphological changes to be dated, with an uncertainty of only a few years to a few decades. Modelling of the tsunami suggests that most of the energy would have been radiated out into the Indian Ocean, detailed modelling around Sumatra matches well with limited observations available. List of earthquakes in Indonesia List of historical earthquakes
41.
1861 Sumatra earthquake
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The 1861 Sumatra earthquake occurred on February 16 and was the last in a sequences of earthquakes that ruptured adjacent parts of the Sumatran segment of the Sunda megathrust. It caused a tsunami which led to several thousand fatalities. The earthquake was felt as far away as the Malay peninsula, the rupture area for the 2005 Nias–Simeulue earthquake is similar to that estimated for the 1861 event. The island of Sumatra lies on the convergent plate boundary between the Indo-Australian Plate and the Eurasian Plate, the major slip events on the subduction zone interface are typically of megathrust type. Historically, great or giant megathrust earthquakes have been recorded in 1797,1833,1861,2004,2005 and 2007, smaller megathrust events have also occurred in the small gaps between the areas that slip during the larger events, in 1935,1984,2000 and 2002. Villages along the side of the Batu Islands were devastated. The combined effects of the earthquake and tsunami caused several thousand fatalities, there is evidence of coseismic uplift of Nias, with exposure of reefs and rock piers. There were six major aftershocks over the seven months, the last of which, on September 27. At least 500 km of coastline were affected by the tsunami with run-ups of up to 7m recorded on the southwest side of Nias, List of earthquakes in Indonesia List of historical earthquakes List of historical tsunamis
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Andaman Sea travel guide from Wikivoyage
