Montserrat is a British Overseas Territory in the Caribbean. The island in the Leeward Islands, part of the chain known as the Lesser Antilles, in the West Indies. Montserrat measures 16 km in length and 11 km in width, with 40 km of coastline. Montserrat is nicknamed "The Emerald Isle of the Caribbean" both for its resemblance to coastal Ireland and for the Irish ancestry of many of its inhabitants. On 18 July 1995, the dormant Soufrière Hills volcano, in the southern part of the island, became active. Eruptions destroyed Montserrat's Georgian era capital city of Plymouth. Between 1995 and 2000, two-thirds of the island's population was forced to flee to the United Kingdom, leaving fewer than 1,200 people on the island as of 1997; the volcanic activity continues affecting the vicinity of Plymouth, including its docking facilities, the eastern side of the island around the former W. H. Bramble Airport, the remnants of which were buried by flows from volcanic activity on 11 February 2010. An exclusion zone, encompassing the southern half of the island to as far north as parts of the Belham Valley, was imposed because of the size of the existing volcanic dome and the resulting potential for pyroclastic activity.
Visitors are not permitted entry into the exclusion zone, but a view of the destruction of Plymouth can be seen from the top of Garibaldi Hill in Isles Bay. Quiet since early 2010, the volcano continues to be monitored by the Montserrat Volcano Observatory. A new town and port are being developed at Little Bay, on the northwest coast of the island. While this construction proceeds, the centre of government and businesses is at Brades. In 1493, Christopher Columbus named the island Santa María de Montserrate, after the Virgin of Montserrat in the Monastery of Montserrat, on Montserrat mountain, near Barcelona in Catalonia, Spain. "Montserrat" means "serrated mountain" in Catalan. Archaeological field work in 2012, in Montserrat's Centre Hills indicated there was an Archaic occupation between 4000 and 2500 BP. Coastal sites show the presence of the Saladoid culture. In November 1493, Christopher Columbus passed Montserrat in his second voyage, after being told that the island was unoccupied due to raids by the Caribs.
A number of Irishmen settled in Montserrat in 1632. The preponderance of Irish in the first wave of European settlers led a leading legal scholar to remark that a "nice question" is whether the original settlers took with them the law of the Kingdom of Ireland insofar as it differed from the law of the Kingdom of England; the Irish being historical allies of the French in their dislike of the English, invited the French to claim the island in 1666, although no troops were sent by France to maintain control. It was captured shortly afterwards by the English and English control of the island was confirmed under the Treaty of Breda the following year. Despite the seizing by force of the island by the English, the island's legal status is that of a "colony acquired by settlement". A neo-feudal colony developed amongst the "redlegs"; the colonists began to transport Sub-Saharan African slaves for labour, as was common to most Caribbean islands. The colonists built an economy based on the production of sugar, rum and sea island cotton, cultivated on large plantations manned by slave labour.
By the late 18th century, numerous plantations had been developed on the island. Many Irish continued to work as indentured servants. On 17 March 1768, slaves failed to achieve freedom; the people of Montserrat celebrate St Patrick's Day as a public holiday due to the slave revolt. Festivities held that week commemorate the culture of Montserrat in song, dance and traditional costumes. In 1782, during the American Revolutionary War, as America's first ally, France captured Montserrat in their war of support of the Americans; the French, not intent on colonizing the island agreed to return the island to Great Britain under the 1783 Treaty of Paris. The Irish constituted the largest proportion of the white population from the founding of the colony in 1628. Many were indentured labourers; the geographer Thomas Jeffrey claimed in The West India Atlas that the majority of those on Montserrat were either Irish or of Irish descent, "so that the use of the Irish language is preserved on the island among the Negroes".
African slaves and Irish colonists of all classes were in constant contact, with sexual relationships being common and a population of mixed descent appearing as a consequence. The Irish were prominent in Caribbean commerce, with their merchants importing Irish goods such as beef, pork and herring, importing slaves. There is indirect evidence that the use of the Irish language continued in Montserrat until at least the middle of the nineteenth century; the Kilkenny diarist and Irish scholar Amhlaoibh Ó Súilleabháin noted in 1831 that he had heard that Irish was still spoken in Montserrat by both black and white inhabitants. A letter by W. F. Butler in The Atheneum quotes an account by a Cork civil servant, C. Cremen, of what he had heard from a retired sailor called John O'Donovan, a fluent Irish speaker: He told me that in the year 1852, when mate of the brig Kaloolah, he went ashore on the island of Montserrat, out of the usual track of shipping, he said he was much surprised to hear the negroes talking Irish among themselves, that he joined in the conversation… The British phonetici
Puerto Rico the Commonwealth of Puerto Rico and called Porto Rico, is an unincorporated territory of the United States located in the northeast Caribbean Sea 1,000 miles southeast of Miami, Florida. An archipelago among the Greater Antilles, Puerto Rico includes the eponymous main island and several smaller islands, such as Mona and Vieques; the capital and most populous city is San Juan. The territory's total population is 3.4 million. Spanish and English are the official languages. Populated by the indigenous Taíno people, Puerto Rico was colonized by Spain following the arrival of Christopher Columbus in 1493, it was contested by French and British, but remained a Spanish possession for the next four centuries. The island's cultural and demographic landscapes were shaped by the displacement and assimilation of the native population, the forced migration of African slaves, settlement from the Canary Islands and Andalusia. In the Spanish Empire, Puerto Rico played a secondary but strategic role compared to wealthier colonies like Peru and New Spain.
Spain's distant administrative control continued up to the end of the 19th century, producing a distinctive creole Hispanic culture and language that combined indigenous and European elements. In 1898, following the Spanish–American War, the United States acquired Puerto Rico under the terms of the Treaty of Paris. Puerto Ricans have been citizens of the United States since 1917, enjoy freedom of movement between the island and the mainland; as it is not a state, Puerto Rico does not have a vote in the United States Congress, which governs the territory with full jurisdiction under the Puerto Rico Federal Relations Act of 1950. However, Puerto Rico does have one non-voting member of the House called a Resident Commissioner; as residents of a U. S. territory, American citizens in Puerto Rico are disenfranchised at the national level and do not vote for president and vice president of the United States, nor pay federal income tax on Puerto Rican income. Like other territories and the District of Columbia, Puerto Rico does not have U.
S. senators. Congress approved a local constitution in 1952, allowing U. S. citizens on the territory to elect a governor. Puerto Rico's future political status has been a matter of significant debate. In early 2017, the Puerto Rican government-debt crisis posed serious problems for the government; the outstanding bond debt had climbed to $70 billion at a time with 12.4% unemployment. The debt had been increasing during a decade long recession; this was the second major financial crisis to affect the island after the Great Depression when the U. S. government, in 1935, provided relief efforts through the Puerto Rico Reconstruction Administration. On May 3, 2017, Puerto Rico's financial oversight board in the U. S. District Court for Puerto Rico filed the debt restructuring petition, made under Title III of PROMESA. By early August 2017, the debt was $72 billion with a 45% poverty rate. In late September 2017, Hurricane Maria made landfall in Puerto Rico; the island's electrical grid was destroyed, with repairs expected to take months to complete, provoking the largest power outage in American history.
Recovery efforts were somewhat slow in the first few months, over 200,000 residents had moved to the mainland State of Florida alone by late November 2017. Puerto Rico is Spanish for "rich port". Puerto Ricans call the island Borinquén – a derivation of Borikén, its indigenous Taíno name, which means "Land of the Valiant Lord"; the terms boricua and borincano derive from Borikén and Borinquen and are used to identify someone of Puerto Rican heritage. The island is popularly known in Spanish as la isla del encanto, meaning "the island of enchantment". Columbus named the island San Juan Bautista, in honor of Saint John the Baptist, while the capital city was named Ciudad de Puerto Rico. Traders and other maritime visitors came to refer to the entire island as Puerto Rico, while San Juan became the name used for the main trading/shipping port and the capital city; the island's name was changed to "Porto Rico" by the United States after the Treaty of Paris of 1898. The anglicized name was used by the U.
S. government and private enterprises. The name was changed back to Puerto Rico by a joint resolution in Congress introduced by Félix Córdova Dávila in 1931; the official name of the entity in Spanish is Estado Libre Asociado de Puerto Rico, while its official English name is Commonwealth of Puerto Rico. The ancient history of the archipelago, now Puerto Rico is not well known. Unlike other indigenous cultures in the New World which left behind abundant archeological and physical evidence of their societies, scant artifacts and evidence remain of the Puerto Rico's indigenous population. Scarce archaeological findings and early Spanish accounts from the colonial era constitute all, known about them; the first comprehensive book on the history of Puerto Rico was written by Fray Íñigo Abbad y Lasierra in 1786, nearly three centuries after the first Spaniards landed on the island. The first known settlers were the Ortoiroid people, an Archaic Period culture of Amerindian hunters and fishermen who migrated from the South American mainland.
Some scholars suggest their settlement dates back about 4,000 years. An archeological dig in 1990 on the island of Vieques found the remains of a man, designated as the "Puerto Ferro Man", dated to around 2000 BC; the Ortoiroid were displaced
A tsunami or tidal wave known as a seismic sea wave, is a series of waves in a water body caused by the displacement of a large volume of water in an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions above or below water all have the potential to generate a tsunami. Unlike normal ocean waves, which are generated by wind, or tides, which are generated by the gravitational pull of the Moon and the Sun, a tsunami is generated by the displacement of water. Tsunami waves do not resemble normal undersea currents or sea waves because their wavelength is far longer. Rather than appearing as a breaking wave, a tsunami may instead resemble a rising tide. For this reason, it is referred to as a "tidal wave", although this usage is not favoured by the scientific community because it might give the false impression of a causal relationship between tides and tsunamis. Tsunamis consist of a series of waves, with periods ranging from minutes to hours, arriving in a so-called "internal wave train".
Wave heights of tens of metres can be generated by large events. Although the impact of tsunamis is limited to coastal areas, their destructive power can be enormous, they can affect entire ocean basins; the 2004 Indian Ocean tsunami was among the deadliest natural disasters in human history, with at least 230,000 people killed or missing in 14 countries bordering the Indian Ocean. The Ancient Greek historian Thucydides suggested in his 5th century BC History of the Peloponnesian War that tsunamis were related to submarine earthquakes, but the understanding of tsunamis remained slim until the 20th century and much remains unknown. Major areas of current research include determining why some large earthquakes do not generate tsunamis while other smaller ones do; the term "tsunami" is a borrowing from the Japanese tsunami 津波, meaning "harbour wave". For the plural, one can either follow ordinary English practice and add an s, or use an invariable plural as in the Japanese; some English speakers alter the word's initial /ts/ to an /s/ by dropping the "t", since English does not natively permit /ts/ at the beginning of words, though the original Japanese pronunciation is /ts/.
Tsunamis are sometimes referred to as tidal waves. This once-popular term derives from the most common appearance of a tsunami, that of an extraordinarily high tidal bore. Tsunamis and tides both produce waves of water that move inland, but in the case of a tsunami, the inland movement of water may be much greater, giving the impression of an high and forceful tide. In recent years, the term "tidal wave" has fallen out of favour in the scientific community, because the causes of tsunamis have nothing to do with those of tides, which are produced by the gravitational pull of the moon and sun rather than the displacement of water. Although the meanings of "tidal" include "resembling" or "having the form or character of" the tides, use of the term tidal wave is discouraged by geologists and oceanographers. A 1969 episode of Hawaii Five-O entitled "Forty Feet High And It Kills!" used the terms "tsunami" and "tidal wave" interchangeably. The term seismic sea wave is used to refer to the phenomenon, because the waves most are generated by seismic activity such as earthquakes.
Prior to the rise of the use of the term tsunami in English, scientists encouraged the use of the term seismic sea wave rather than tidal wave. However, like tsunami, seismic sea wave is not a accurate term, as forces other than earthquakes – including underwater landslides, volcanic eruptions, underwater explosions, land or ice slumping into the ocean, meteorite impacts, the weather when the atmospheric pressure changes rapidly – can generate such waves by displacing water. While Japan may have the longest recorded history of tsunamis, the sheer destruction caused by the 2004 Indian Ocean earthquake and tsunami event mark it as the most devastating of its kind in modern times, killing around 230,000 people; the Sumatran region is accustomed to tsunamis, with earthquakes of varying magnitudes occurring off the coast of the island. Tsunamis are an underestimated hazard in the Mediterranean Sea and parts of Europe. Of historical and current importance are the 1755 Lisbon earthquake and tsunami, the 1783 Calabrian earthquakes, each causing several tens of thousands of deaths and the 1908 Messina earthquake and tsunami.
The tsunami claimed more than 123,000 lives in Sicily and Calabria and is among the most deadly natural disasters in modern Europe. The Storegga Slide in the Norwegian Sea and some examples of tsunamis affecting the British Isles refer to landslide and meteotsunamis predominantly and less to earthquake-induced waves; as early as 426 BC the Greek historian Thucydides inquired in his book History of the Peloponnesian War about the causes of tsunami, was the first to argue that ocean earthquakes must be the cause. The cause, in my opinion, of this phenomenon must be sought in the earthquake. At the point where its shock has been the most violent the sea is driven back, recoiling with redoubled force, causes the inundation. Without an earthquake I do not see; the Roman historian Ammianus Marcellinus described the typical sequence of a tsunami, including an incipient earthquake, the sudden retreat of the sea and a followin
Barbados is an island country in the Lesser Antilles of the West Indies, in the Caribbean region of North America. It is 34 kilometres in length and up to 23 km in width, covering an area of 432 km2, it is situated in the western area of the North Atlantic and 100 km east of the Windward Islands and the Caribbean Sea. It is about 168 km east of both the countries of Saint Lucia and Saint Vincent and the Grenadines and 400 km north-east of Trinidad and Tobago. Barbados is outside the principal Atlantic hurricane belt, its capital and largest city is Bridgetown. Inhabited by Kalinago people since the 13th century, prior to that by other Amerindians, Barbados was visited by Spanish navigators in the late 15th century and claimed for the Spanish Crown, it first appeared in a Spanish map in 1511. The Portuguese claimed the island in 1536, but abandoned it, with their only remnants being an introduction of wild hogs for a good supply of meat whenever the island was visited. An English ship, the Olive Blossom, arrived in Barbados in 1625.
In 1627, the first permanent settlers arrived from England, it became an English and British colony. As a wealthy sugar colony, it became an English centre of the African slave trade until that trade was outlawed in 1807, with final emancipation of slaves in Barbados occurring over a period of years from 1833. On 30 November 1966, Barbados became an independent state and Commonwealth realm with Elizabeth II as its queen, it has a population of 287,010 people, predominantly of African descent. Despite being classified as an Atlantic island, Barbados is considered to be a part of the Caribbean, where it is ranked as a leading tourist destination. Forty percent of the tourists come from the UK, with the US and Canada making up the next large groups of visitors to the island; the name "Barbados" is from either the Portuguese term Os Barbados or the Spanish equivalent, Los Barbados, both meaning "the bearded ones". It is unclear whether "bearded" refers to the long, hanging roots of the bearded fig-tree, indigenous to the island, or to the bearded Caribs who once inhabited the island, or, more fancifully, to a visual impression of a beard formed by the sea foam that sprays over the outlying reefs.
In 1519, a map produced by the Genoese mapmaker Visconte Maggiolo showed and named Barbados in its correct position. Furthermore, the island of Barbuda in the Leewards is similar in name and was once named "Las Barbudas" by the Spanish, it is uncertain. One lesser-known source points to earlier revealed works predating contemporary sources indicating it could have been the Spanish. Many if not most believe the Portuguese, en route to Brazil, were the first Europeans to come upon the island; the original name for Barbados in the Pre-Columbian era was Ichirouganaim, according to accounts by descendants of the indigenous Arawakan-speaking tribes in other regional areas, with possible translations including "Red land with white teeth" or "Redstone island with teeth outside" or "Teeth". Colloquially, Barbadians refer to their home island as "Bim" or other nicknames associated with Barbados, including "Bimshire"; the origin is uncertain. The National Cultural Foundation of Barbados says that "Bim" was a word used by slaves, that it derives from the Igbo term bém from bé mụ́ meaning'my home, kind', the Igbo phoneme in the Igbo orthography is close to.
The name could have arisen due to the large percentage of enslaved Igbo people from modern-day southeastern Nigeria arriving in Barbados in the 18th century. The words'Bim' and'Bimshire' are recorded in the Oxford English Dictionary and Chambers Twentieth Century Dictionaries. Another possible source for'Bim' is reported to be in the Agricultural Reporter of 25 April 1868, where the Rev. N. Greenidge suggested the listing of Bimshire as a county of England. Expressly named were "Wiltshire, Hampshire and Bimshire". Lastly, in the Daily Argosy of 1652, there is a reference to Bim as a possible corruption of'Byam', the name of a Royalist leader against the Parliamentarians; that source suggested the followers of Byam became known as'Bims' and that this became a word for all Barbadians. Amerindian settlement of Barbados dates to about the 4th to 7th centuries AD, by a group known as the Saladoid-Barrancoid; the Arawaks from South America became dominant around 800 AD, maintained that status until around 1200.
In the 13th century, the Kalinago arrived from South America. The Spanish and Portuguese claimed Barbados from the late 16th to the 17th centuries; the Arawaks are believed to have fled to neighbouring islands. Apart from displacing the Caribs, the Spanish and Portuguese made little impact and left the island uninhabited; some Arawaks continue to live in Barbados. In the early years the majority of the labour was provided by European indentured servants English and Scottish, with enslaved Africans and enslaved Amerindian providing little of the workforce. During the Cromwellian era this included a large number of prisoners-of-war and people who were illicitly kidnapped, who were forcibly transported to the island and sold as servants; these last two groups were predominately Irish, as several thousand were infamously rounded up by Engli
An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to toss people around and destroy whole cities; the seismicity, or seismic activity, of an area is the frequency and size of earthquakes experienced over a period of time. The word tremor is used for non-earthquake seismic rumbling. At the Earth's surface, earthquakes manifest themselves by shaking and displacing or disrupting the ground; when the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can trigger landslides, volcanic activity. In its most general sense, the word earthquake is used to describe any seismic event—whether natural or caused by humans—that generates seismic waves. Earthquakes are caused by rupture of geological faults, but by other events such as volcanic activity, mine blasts, nuclear tests.
An earthquake's point of initial rupture is called its hypocenter. The epicenter is the point at ground level directly above the hypocenter. Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane; the sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the fault surface that increase the frictional resistance. Most fault surfaces do have such asperities and this leads to a form of stick-slip behavior. Once the fault has locked, continued relative motion between the plates leads to increasing stress and therefore, stored strain energy in the volume around the fault surface; this continues until the stress has risen sufficiently to break through the asperity allowing sliding over the locked portion of the fault, releasing the stored energy. This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface, cracking of the rock, thus causing an earthquake.
This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory. It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake fracture growth or is converted into heat generated by friction. Therefore, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior. There are three main types of fault, all of which may cause an interplate earthquake: normal and strike-slip. Normal and reverse faulting are examples of dip-slip, where the displacement along the fault is in the direction of dip and movement on them involves a vertical component. Normal faults occur in areas where the crust is being extended such as a divergent boundary. Reverse faults occur in areas.
Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip. Reverse faults those along convergent plate boundaries are associated with the most powerful earthquakes, megathrust earthquakes, including all of those of magnitude 8 or more. Strike-slip faults continental transforms, can produce major earthquakes up to about magnitude 8. Earthquakes associated with normal faults are less than magnitude 7. For every unit increase in magnitude, there is a thirtyfold increase in the energy released. For instance, an earthquake of magnitude 6.0 releases 30 times more energy than a 5.0 magnitude earthquake and a 7.0 magnitude earthquake releases 900 times more energy than a 5.0 magnitude of earthquake. An 8.6 magnitude earthquake releases the same amount of energy as 10,000 atomic bombs like those used in World War II. This is so because the energy released in an earthquake, thus its magnitude, is proportional to the area of the fault that ruptures and the stress drop.
Therefore, the longer the length and the wider the width of the faulted area, the larger the resulting magnitude. The topmost, brittle part of the Earth's crust, the cool slabs of the tectonic plates that are descending down into the hot mantle, are the only parts of our planet which can store elastic energy and release it in fault ruptures. Rocks hotter than about 300 °C flow in response to stress; the maximum observed lengths of ruptures and mapped faults are 1,000 km. Examples are the earthquakes in Chile, 1960; the longest earthquake ruptures on strike-slip faults, like the San Andreas Fault, the North Anatolian Fault in Turkey and the Denali Fault in Alaska, are about half to one third as long as the lengths along subducting plate margins, those along normal faults are shorter. The most important parameter controlling the maximum earthquake magnitude on a fault is however not the maximum available length, but the available width because the latter varies by a factor of 20. Along converging plate margins, the dip angle of the rupture plane is shallow about 10 de
A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. A thrust fault is a type of reverse fault. If the angle of the fault plane is lower and the displacement of the overlying block is large the fault is called an overthrust or overthrust fault. Erosion can remove part of the overlying block, creating a fenster – when the underlying block is exposed only in a small area; when erosion removes most of the overlying block, leaving island-like remnants resting on the lower block, the remnants are called klippen. If the fault plane terminates before it reaches the Earth's surface, it is referred to as a blind thrust fault; because of the lack of surface evidence, blind thrust faults are difficult to detect until they rupture. The destructive 1994 quake in Northridge, was caused by a undiscovered blind thrust fault; because of their low dip, thrusts are difficult to appreciate in mapping, where lithological offsets are subtle and stratigraphic repetition is difficult to detect in peneplain areas.
Thrust faults those involved in thin-skinned style of deformation, have a so-called ramp-flat geometry. Thrusts propagate along zones of weakness within a sedimentary sequence, such as mudstones or salt layers, these parts of the thrust are called decollements. If the effectiveness of the decollement becomes reduced, the thrust will tend to cut up the section to a higher stratigraphic level until it reaches another effective decollement where it can continue as bedding parallel flat; the part of the thrust linking the two flats is known as a ramp and forms at an angle of about 15°-30° to the bedding. Continued displacement on a thrust over a ramp produces a characteristic fold geometry known as a ramp anticline or, more as a fault-bend fold. Fault-propagation folds form at the tip of a thrust fault where propagation along the decollement has ceased but displacement on the thrust behind the fault tip is continuing; the continuing displacement is accommodated by formation of an asymmetric anticline-syncline fold pair.
As displacement continues the thrust tip starts to propagate along the axis of the syncline. Such structures are known as tip-line folds; the propagating thrust tip may reach another effective decollement layer and a composite fold structure will develop with characteristics of both fault-bend and fault-propagation folds. Duplexes occur where there are two decollement levels close to each other within a sedimentary sequence, such as the top and base of a strong sandstone layer bounded by two weak mudstone layers; when a thrust that has propagated along the lower detachment, known as the floor thrust, cuts up to the upper detachment, known as the roof thrust, it forms a ramp within the stronger layer. With continued displacement on the thrust, higher stresses are developed in the footwall of the ramp due to the bend on the fault; this may cause renewed propagation along the floor thrust until it again cuts up to join the roof thrust. Further displacement takes place via the newly created ramp.
This process may repeat many times, forming a series of fault bounded thrust slices known as imbricates or horses, each with the geometry of a fault-bend fold of small displacement. The final result is a lozenge shaped duplex. Most duplexes have only small displacements on the bounding faults between the horses and these dip away from the foreland; the displacement on the individual horses is greater, such that each horse lies more or less vertically above the other, this is known as an antiformal stack or imbricate stack. If the individual displacements are greater still the horses have a foreland dip. Duplexing is a efficient mechanism of accommodating shortening of the crust by thickening the section rather than by folding and deformation. Large overthrust faults occur in areas; these conditions exist in the orogenic belts that result from either two continental tectonic collisions or from subduction zone accretion. The resultant compressional forces produce mountain ranges; the Himalayas, the Alps, the Appalachians are prominent examples of compressional orogenies with numerous overthrust faults.
Thrust faults occur in the foreland basin. Here, compression does not result in appreciable mountain building, accommodated by folding and stacking of thrusts. Instead thrust faults cause a thickening of the stratigraphic section. Foreland basin thrusts usually observe the ramp-flat geometry, with thrusts propagating within units at a low angle "flats" and moving up-section in steeper ramps where they offset stratigraphic units. Identifying ramps where they occur within units is problematic. Thrusts and duplexes are found in accretionary wedges in the ocean trench margin of subduction zones, where oceanic sediments are scraped off the subducted plate and accumulate. Here, the accretionary wedge must thicken by up to 200% and this is achieved by stacking thrust fault upon thrust fault in a melange of disrupted rock with chaotic folding. Here, ramp flat geometries are not observed because the compressional force is at a steep angle to the sedimentary layering. Thrust faults were unrecognised until the work of Arnold Escher von der Linth, Albert Heim and Marcel Alexandre Bertrand in the Alps working on the Glarus Thrust.
Trinidad is the larger and more populous of the two major islands of Trinidad and Tobago. The island lies 11 km off the northeastern coast of Venezuela and sits on the continental shelf of South America. Though geographically part of the South American continent, from a socio-economic standpoint it is referred to as the southernmost island in the Caribbean. With an area of 4,768 km2, it is the fifth largest in the West Indies; the original name for the island in the Arawaks' language was Iëre which meant "Land of the Hummingbird". Christopher Columbus renamed it "La Isla de la Trinidad", fulfilling a vow he had made before setting out on his third voyage; this has since been shortened to Trinidad. Caribs and Arawaks lived in Trinidad long before Christopher Columbus encountered the islands on his third voyage on 31 July 1498; the island remained Spanish until 1797, but it was settled by French colonists from the French Caribbean Martinique. In 1889 the two islands became a single British Crown colony.
Trinidad and Tobago obtained self-governance in 1958 and independence from the United Kingdom in 1962. Major landforms include the hills of the Northern and Southern Ranges, the Caroni and Oropouche Swamps, the Caroni and Naparima Plains. Major river systems include the Caroni and South Oropouche and Ortoire Rivers. There are many other natural landforms such as waterfalls. Trinidad has two seasons per calendar year: the dry season. El Cerro del Aripo, at 940 metres, is the highest point in Trinidad, it is part of the Aripo Massif and is located in the Northern Range on the island, northeast of the town of Arima. The demographics of Trinidad and Tobago reflect the diversity of this southern-most country in the West Indies, it is sometimes known as a "rainbow island" or more fondly "a callaloo". There is a wide range of ethnicity and culture; the variety of denominations has followed this pattern for decades: Protestant 32.1%, Roman Catholic 21.6%, Hindu 18.2%, Muslim 5%, Jehovah's Witness 1.5%, other 8.4%, none 2.2%, unspecified 11.1%.
Religion in Trinidad and Tobago consists of a diverse array of denominations including Roman Catholic, other Christian denominations and Muslim faiths. There are a minority of people who are followers of Traditional African religions, Afro-American religions, Amerindian religions, Sikhism, Chinese folk religion and Bahá'í. Catholicism constitutes the largest religious denomination of the country; as of the 2011 Trinidad and Tobago Census, the population was 35.43% East Indian, 34.22% African, 7.66% Mixed – African and East Indian, 15.16% Mixed – Other. Venezuela has had a great impact on Trinidad's culture, such as introducing the music style parang to the island. Many groups overlap. For example, a "Dougla" is a person of African and East Indian descent who may identify as being part of either group. There are multiple festivals featuring the music of the Caribbean and the steelpan, which originated in Trinidad and is the country's national instrument; these festivals include the world-renowned Carnival, J'ouvert, Panorama, the national steel pan competition.
Trinidad has many public holidays, such as Indian Arrival Day, Emancipation Day, Independence Day, Republic Day, Labour Day, Boxing Day, New Year's Day, Phagwah, Eid al-Fitr, Corpus Christi, Good Friday, Easter Monday and Spiritual Baptist/Shouter Liberation Day. There are places that can be visited that hold cultural significance, such as Mount Saint Benedict and the Temple in the Sea. Further information: Natural history of Trinidad and Tobago The island of Trinidad has a rich biodiversity; the fauna is overwhelmingly of South American origin. There are about 100 species of mammals including the Guyanan red howler monkey, the collared peccary, the red brocket deer, the ocelot and about 70 species of bats. There are over 400 species of birds including the endemic Trinidad piping-guan. Reptiles are well represented, with about 92 recorded species including the largest species of snake in the world, the green anaconda, the spectacled caiman, one of the largest lizards in the Americas, the green iguana.
The largest of turtles nests on Trinidad's northern beaches. There are 37 recorded frog species, including the tiny El Tucuche golden tree frog, the more widespread huge cane toad. About 43 species of freshwater fishes are known including the well known guppy, it is estimated that there are at least 80,000 arthropods, at least 600 species of butterflies. The economy of Trinidad and Tobago is diversified, based to a large extent on oil, natural gas and agriculture, it is one of the leading gas-based export centres in the world, being the leading exporter of ammonia and methanol and among the top five exporters of liquefied natural gas. This has allowed Trinidad to capitalise on the biggest mineral reserves within its territories, it is an oil-rich country and stable economically. The Venezuela Tertiary Basin is a subsidence basin formed between the Caribbean and South American plates, is bounded on the north by the coast ranges of Venezuela and the Northern Range of Trinidad, bounded on the south by the Guayana Shield.
This Guayana shield supplied fine-grained clastic sediments, which with the subsidence, formed a regional negative gravity anomaly and growth faults. Oil and g