1.
Richter magnitude scale
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The Richter magnitude scale assigns a magnitude number to quantify the size of an earthquake. As measured with a seismometer, an earthquake that registers 5.0 on the Richter scale has a shaking amplitude 10 times greater than an earthquake that registered 4.0 at the same distance. This means that, for instance, an earthquake of magnitude 5 releases 31.6 times as energy as an earthquake of magnitude 4. In the United States, the Richter scale was succeeded in the 1970s by the moment magnitude scale, the moment magnitude scale is now the scale used by the United States Geological Survey to estimate magnitudes for all modern large earthquakes. Richter derived his earthquake-magnitude scale from the apparent magnitude scale used to measure the brightness of stars and that fixed measure was chosen to avoid negative values for magnitude, given that the slightest earthquakes that could be recorded and located at the time were around magnitude 3.0. The Richter magnitude scale itself has no limit, and contemporary seismometers can register, record. M L was not designed to be applied to data with distances to the hypocenter of the earthquake that were greater than 600 km. Later, to express the size of earthquakes around the planet, Gutenberg and Richter developed a surface wave magnitude scale and these are types of waves that are recorded at teleseismic distances. The two scales were adjusted such that they were consistent with the M L scale and that adjustment succeeded better with the M s scale than with the M b scale. Each scale saturates when the earthquake is greater than magnitude 8.0, because of this, researchers in the 1970s developed the moment magnitude scale. The older magnitude-scales were superseded by methods for calculating the seismic moment, about the origins of the Richter magnitude scale, C. F. Richter said, I found a paper by Professor K. Wadati of Japan in which he compared large earthquakes by plotting the maximum ground motion against distance to the epicenter. I tried a similar procedure for our stations, but the range between the largest and smallest magnitudes seemed unmanageably large, dr. Beno Gutenberg then made the natural suggestion to plot the amplitudes logarithmically. I was lucky, because logarithmic plots are a device of the devil, the particular instrument used would become saturated by strong earthquakes and unable to record high values. The scale was replaced in the 1970s by the moment magnitude scale, for earthquakes adequately measured by the Richter scale, anything above 5 is classified as a risk by the USGS. Several scales have historically described as the Richter scale, especially the local magnitude M L. In addition, the body wave magnitude, m b, a couple of new techniques to measure magnitude are in the development stage by seismologists. All magnitude scales have been designed to give similar results
2.
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
3.
England
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England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west, the Irish Sea lies northwest of England and the Celtic Sea lies to the southwest. England is separated from continental Europe by the North Sea to the east, the country covers five-eighths of the island of Great Britain in its centre and south, and includes over 100 smaller islands such as the Isles of Scilly, and the Isle of Wight. England became a state in the 10th century, and since the Age of Discovery. The Industrial Revolution began in 18th-century England, transforming its society into the worlds first industrialised nation, Englands terrain mostly comprises low hills and plains, especially in central and southern England. However, there are uplands in the north and in the southwest, the capital is London, which is the largest metropolitan area in both the United Kingdom and the European Union. In 1801, Great Britain was united with the Kingdom of Ireland through another Act of Union to become the United Kingdom of Great Britain and Ireland. In 1922 the Irish Free State seceded from the United Kingdom, leading to the latter being renamed the United Kingdom of Great Britain, the name England is derived from the Old English name Englaland, which means land of the Angles. The Angles were one of the Germanic tribes that settled in Great Britain during the Early Middle Ages, the Angles came from the Angeln peninsula in the Bay of Kiel area of the Baltic Sea. The earliest recorded use of the term, as Engla londe, is in the ninth century translation into Old English of Bedes Ecclesiastical History of the English People. According to the Oxford English Dictionary, its spelling was first used in 1538. The earliest attested reference to the Angles occurs in the 1st-century work by Tacitus, Germania, the etymology of the tribal name itself is disputed by scholars, it has been suggested that it derives from the shape of the Angeln peninsula, an angular shape. An alternative name for England is Albion, the name Albion originally referred to the entire island of Great Britain. The nominally earliest record of the name appears in the Aristotelian Corpus, specifically the 4th century BC De Mundo, in it are two very large islands called Britannia, these are Albion and Ierne. But modern scholarly consensus ascribes De Mundo not to Aristotle but to Pseudo-Aristotle, the word Albion or insula Albionum has two possible origins. Albion is now applied to England in a poetic capacity. Another romantic name for England is Loegria, related to the Welsh word for England, Lloegr, the earliest known evidence of human presence in the area now known as England was that of Homo antecessor, dating to approximately 780,000 years ago. The oldest proto-human bones discovered in England date from 500,000 years ago, Modern humans are known to have inhabited the area during the Upper Paleolithic period, though permanent settlements were only established within the last 6,000 years
4.
Essex
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Essex /ˈɛsᵻks/ is a county in England immediately north-east of London. It borders the counties of Suffolk and Cambridgeshire to the north, Hertfordshire to the west, Kent across the estuary of the River Thames to the south, the county town is Chelmsford, which is the only city in the county. Essex occupies the part of the old Kingdom of Essex, before this. As well as areas, the county also includes London Stansted Airport, the new towns of Basildon and Harlow, Lakeside Shopping Centre, the port of Tilbury. Originally recorded in AD527, Essex occupied territory to the north of the River Thames, incorporating all of what later became Middlesex and its territory was later restricted to lands east of the River Lea. In changes before the Norman conquest the East Saxons were subsumed into the Kingdom of England and, following the Norman conquest, Essex became a county. During the medieval period, much of the area was designated a Royal forest, including the county in a period to 1204. Gradually, the subject to forest law diminished, but at various times included the forests of Becontree, Chelmsford, Epping, Hatfield, Ongar. County-wide administration Essex County Council was formed in 1889, however County Boroughs of West Ham, Southend-on-Sea and East Ham formed part of the county but were unitary authorities. 12 boroughs and districts provide more localised services such as rubbish and recycling collections, leisure and planning, parish-level administration – changes A few Essex parishes have been transferred to other counties. Before 1889, small areas were transferred to Hertfordshire near Bishops Stortford, Essex became part of the East of England Government Office Region in 1994 and was statistically counted as part of that region from 1999, having previously been part of the South East England region. Two unitary authorities In 1998 the boroughs of Southend-on-Sea and Thurrock were granted autonomy from the county of Essex after successful requests to become unitary authorities. Essex Police covers the county and the two unitary authorities. The county council chamber and main headquarters is at the County Hall in Chelmsford, before 1938 the council regularly met in London near Moorgate, which with significant parts closer to that point and the dominance of railways had been more convenient than any place in the county. It currently has 75 elected councillors, before 1965, the number of councillors reached over 100. The highest point of the county of Essex is Chrishall Common near the village of Langley, close to the Hertfordshire border, the pattern of settlement in the county is diverse. Epping Forest also acts as a barrier to the further spread of London. Part of the southeast of the county, already containing the population centres of Basildon, Southend and Thurrock, is within the Thames Gateway
5.
Virley
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Virley is a village in the Colchester borough of Essex, England and forms part of the Winstred Hundred civil parish. According to the 2001 census it had a population of 61, the village is about seven miles south of Colchester. Virley is among the villages which suffered damage from the 1884 Colchester earthquake, the village church was destroyed in the quake
6.
Colchester
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Colchester /ˈkoʊltʃɛstər/ is an historic large town and the largest settlement within the borough of Colchester in the county of Essex. As the oldest recorded Roman town in Britain, Colchester is claimed to be the oldest town in Britain and it was for a time the capital of Roman Britain, and is a member of the Most Ancient European Towns Network. Colchester is some 50 miles northeast of London and is connected to the capital by the A12 road and it is seen as a popular town for commuters, and is less than 30 miles away from Stansted Airport and 20 miles from the passenger ferry port of Harwich. Colchester is home to Colchester Castle and Colchester United Football Club and it has a Conservative Member of Parliament, Will Quince, who was elected in the 2015 General Election. The River Colne runs through the town and it is a widely held belief that the name Colchester is derived from the Latin words Colonia and Castra, meaning fortifications. The earliest forms of the name Colchester are Colenceaster and Colneceastre from the 10th century, in this way of interpreting the name, the River Colne which runs through the town takes its name from Colonia as well. Cologne also gained its name from a similar etymology, ekwall went as far as to say it has often been held that Colchester contains as first element colonia. This derivation is ruled out of court by the fact that Colne is the name of old villages situated a good many miles from Colchester. The identification of Colonia with Colchester is doubtful, from these deposits beneath the town have been found Palaeolithic flint tools, including at least six Acheulian handaxes. Further flint tools made by hunter gatherers living in the Colne Valley during the Mesolithic have been discovered and this included a pit found at Culver Street containing a ritually placed Neolithic grooved ware pot, as well as find spots containing later Deverel-Rimbury bucket urns. Before the Roman conquest of Britain it was already a centre of power for Cunobelin – known to Shakespeare as Cymbeline – king of the Catuvellauni, who minted coins there. Its Celtic name, Camulodunon, variously represented as CA, CAM, CAMV, CAMVL and CAMVLODVNO on the coins of Cunobelinus, during the 30s AD Camulodunon controlled a large swathe of Southern and Eastern Britain, with Cunobelin called King of the Britons by Roman writers. Camulodunon is considered one of possible sites around Britain for the legendary Camelot of King Arthur. Soon after the Roman conquest of Britain in AD43, a Roman legionary fortress was established, later, when the Roman frontier moved outwards and the twentieth legion had moved to the west, Camulodunum became a colonia named in a second-century inscription as Colonia Victricensis. This contained a large and elaborate Temple to the Divine Claudius, Colchester is home to two of the five Roman theatres found in Britain, the one at Gosbecks being the largest in Britain, able to seat 5,000. Camulodunum served as a provincial Roman capital of Britain, but was attacked and destroyed during Boudicas rebellion in AD61, sometime after the destruction, London became the capital of the province of Britannia. Colchesters town walls c.3,000 yd. long were built c. 65–80 A. D. when the Roman town was rebuilt after the Boudicca rebellion. In 2004, Colchester Archaeological Trust discovered the remains of a Roman Circus underneath the Garrison in Colchester, the Roman town of Camulodunum, officially known as Colonia Victricensis, reached its peak in the Second and Third centuries AD
7.
Earthquake
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An earthquake is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earths 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 people around. The seismicity or seismic activity of an area refers to the frequency, type, Earthquakes are measured using measurements from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe and these two scales are numerically similar over their range of validity. Magnitude 3 or lower earthquakes are mostly imperceptible or weak and magnitude 7 and over potentially cause damage over larger areas. The largest earthquakes in historic times have been of magnitude slightly over 9, intensity of shaking is measured on the modified Mercalli scale. The shallower an earthquake, the damage to structures it causes. At the Earths surface, earthquakes manifest themselves by shaking and sometimes displacement of the ground, when the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally 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 mostly by rupture of faults, but also by other events such as volcanic activity, landslides, mine blasts. An earthquakes point of rupture is called its focus or 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 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, suddenly allowing sliding over the portion of the fault. This energy is released as a combination of radiated elastic strain seismic waves, frictional heating of the fault surface and 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 a total energy is radiated as seismic energy. Most of the energy is used to power the earthquake fracture growth or is converted into heat generated by friction
8.
United Kingdom
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The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom or Britain, is a sovereign country in western Europe. Lying off the north-western coast of the European mainland, the United Kingdom includes the island of Great Britain, Northern Ireland is the only part of the United Kingdom that shares a land border with another sovereign state—the Republic of Ireland. The Irish Sea lies between Great Britain and Ireland, with an area of 242,500 square kilometres, the United Kingdom is the 78th-largest sovereign state in the world and the 11th-largest in Europe. It is also the 21st-most populous country, with an estimated 65.1 million inhabitants, together, this makes it the fourth-most densely populated country in the European Union. The United Kingdom is a monarchy with a parliamentary system of governance. The monarch is Queen Elizabeth II, who has reigned since 6 February 1952, other major urban areas in the United Kingdom include the regions of Birmingham, Leeds, Glasgow, Liverpool and Manchester. The United Kingdom consists of four countries—England, Scotland, Wales, the last three have devolved administrations, each with varying powers, based in their capitals, Edinburgh, Cardiff and Belfast, respectively. The relationships among the countries of the UK have changed over time, Wales was annexed by the Kingdom of England under the Laws in Wales Acts 1535 and 1542. A treaty between England and Scotland resulted in 1707 in a unified Kingdom of Great Britain, which merged in 1801 with the Kingdom of Ireland to form the United Kingdom of Great Britain and Ireland. Five-sixths of Ireland seceded from the UK in 1922, leaving the present formulation of the United Kingdom of Great Britain, there are fourteen British Overseas Territories. These are the remnants of the British Empire which, at its height in the 1920s, British influence can be observed in the language, culture and legal systems of many of its former colonies. The United Kingdom is a country and has the worlds fifth-largest economy by nominal GDP. The UK is considered to have an economy and is categorised as very high in the Human Development Index. It was the worlds first industrialised country and the worlds foremost power during the 19th, the UK remains a great power with considerable economic, cultural, military, scientific and political influence internationally. It is a nuclear weapons state and its military expenditure ranks fourth or fifth in the world. The UK has been a permanent member of the United Nations Security Council since its first session in 1946 and it has been a leading member state of the EU and its predecessor, the European Economic Community, since 1973. However, on 23 June 2016, a referendum on the UKs membership of the EU resulted in a decision to leave. The Acts of Union 1800 united the Kingdom of Great Britain, Scotland, Wales and Northern Ireland have devolved self-government
