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What is earth quake and why its occurs An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured using observations from seismometers. The moment magnitude is the most common scale on which earthquakes larger than approximately 5 are reported for the entire globe. tectonic plates on Earth. Tectonic plates are pieces of the Earth's crust and uppermost mantle, together referred to as thelithosphere. Understanding how and where hydrothermal vents and other high-energy phenomena occur on the seafloor requires a closer look at the Earth's structure and the forces at work deep within the planet. The Earth's inner coreis a solid sphere composed mostly of iron. It is about 2,400 kilometers (1,500 mi) in diameter and is believed to be as hot as 6650 C (12000 F). This heat is probably generated by the radioactive decay of uranium and other elements. The inner core is bordered by aliquid outer core that is 4700 C (8500F). Surrounding the outer core is the mantle,which is composed of hot, molten rock called magma. The churning of the magma, caused by the heat rising from the core, generates pressure on the Earth's surface layer, or crust. The crust is very thin compared to the other layers, ranging in thickness from only about 3.2 kilometers (2 mi) in some areas of the ocean floor to some 121 kilometers (75 mi) deep under mountains. The crust is composed of plates on which the continents and oceans rest. Like giant rafts, these plates move slowly on the magma beneath them. The plates may move apart, collide, and slide past each other, resulting in such high-energy phenomena as hydrothermal vents, volcanoes, and earthquakes.

How Plates Move on the Earth Powered by forces originating in Earths radioactive, solid iron inner core, these tectonic plates move ponderously about at varying speeds and in different directions atop a layer of much hotter, softer, more malleable rock called the athenosphere. Because of the high temperatures and immense pressures found here, the uppermost part of the athenosphere is deformed and flows almost plastically just beneath the Earths surface. This characteristic of the athenosphere to flow allows the plates to inch along on their endless journeys around the surface of the earth, moving no faster than human fingernails grow.

One idea that might explain the ability of the athenosphere to flow is the idea of convection currents. When mantle rocks near the radioactive core are heated, they become less dense than the cooler, upper mantle rocks. These warmer rocks rise while the cooler rocks sink, creating slow, vertical currents within the mantle (these convection currents move mantle rocks only a few centimeters a year). This movement of warmer and cooler mantle rocks, in turn, creates pockets of circulation within the mantle called convection cells. The circulation of these convection cells could very well be the driving force behind the movement of tectonic plates over the athenosphere.

Movement of plates in the world

China geography and locationChina is Located in Southeast Asia along the coastline of the Pacific Ocean, China is the world's third largest country, after Russia and Canada. With an area of 9.6 million square kilometers and a coastline of 18,000 kilometers, its shape on the map is like a rooster. It reaches Mohe in Heilongjiang Province as its northern end, Zengmu Ansha (or James Shoal) to the south, Pamirs to the west, and expands to the eastern border at the conjunction of the Heilongjiang (Amur) River and the Wusuli (Ussuri) River, spanning about 50 degrees of latitude and 62 degrees of longitude. China is bordered by 14 countries -- Korea, Vietnam, Laos, Burma, India, Bhutan, Nepal, Pakistan, Afghanistan, Tajikistan, Kyrgyzstan, Kazakstan, Mongolia, and Russia. Marine-side neighbors include eight countries -- North Korea, Korea, Japan, Philippines, Brunei, Indonesia, Malaysia and Vietnam. China stretches some 5,026 kilometers (3,123 mi) across the East Asian landmass bordering the East China Sea, Korea Bay, Yellow Sea, and South China Sea, between North Korea and Vietnam in a changing configuration of broad plains, expansive deserts, and loftymountain ranges, including vast areas of inhospitable terrain. The eastern half of the country, its seacoast fringed with offshore islands, is a region of fertile lowlands, foothills and mountains, deserts, steppes, and subtropical areas. The western half of China is a region of sunken basins, rolling plateaus, and towering massifs, including a portion of the highest tableland on earth.

Introduction of earthquakes in china hina is principally a part of the Eurasian plate, but the margins of the Indian and Philippine Sea plates are involved in the Himalayas and in the Coastal Range of Taiwan, respectively. Within the

Eurasian plate, the Cathaysian paleoplate is separated from the Angaraian paleoplate by the Junggar-Hegen suture, which contains Paleozoic ophiolites and rare blueschists. The three microplates of the Cathaysian paleoplate consist of Precambrian cratons and/or Phanerozoic accretionary fold belts. These coalesced Precambrian cratons record at least six stages of intense orogeny before cratonization. The Paleozoic to Cenozoic accretionary fold belts of China can be correlated with similar events now found in west Pacific-, Andean-, and Atlantictype active continental margins. Ophiolites occupying many of these tectonic zones provide evidence for the age and igneous history of oceanic crust formed during the Paleozoic to Cenozoic. The presence of blueschist in some of these Chinese sutures reveals evidence of large-scale subduction and tectonic exhumation during consolidation of the Eurasian plate. Cenozoic collision of the Eurasian and Indian plates produced deformation and uplift of the Himalayas, strongly influencing the tectonics of western China. In contrast, MesozoicTertiaryevolution of eastern China is typical basin-range geology, similar to that of the western United States, which included development of deep sedimentary basins along with calc-alkaline plutonic and volcanic activity associated with crustal thinning and high heat flow. The complicated tectonic evolution of China is greatly illuminated by the presence of ophiolites and blueschists in Proterozoic to Tertiary convergent boundaries. These petrotectonic assemblages provide evidence of an extremely mobile history of plate movement in China.

Movement of plates in china region

Collision of India with the Asian mainland during the earliest Eocene (~50 Ma) has resulted in the growth of the world's largest orogenic belt, the Himalayas, and the associated Tibetan plateau. The seimotectonic tectonic evolution of China is characterized by the merger of several microcontinents throughout the entire Phanerozoic.

The collision and associated convergence and extension has created 64 major tectonic zones in China, which can be subdivided into a smaller number of tectonic "regions"

Seismic plates of china region

Thus, China is located in one of the most active seismic regions of the world that has been plagued by numerous destructive earthquakes during its long history. The most significant of the historical earthquakes, in terms of lives lost, was that which occurred in 1556. However, since 1900 China has experienced several more destructive earthquakes. The most destructive earthquakes of the 20th Century were those of 1927 in Tsinghai, of 1932 in Gansu, of 1933 in Sichuan, of 1969 in Bohai Sea, of 1970 in Tonghai (Yunnan), of 1974 in Zhaotong (Yunnan), of 1975 in Haicheng, and of 1976 in Tangshan (Hebei Province) . The more recent earthquake of May 12, 2008 in Sichuan Province was the latest of the more destructive earthquakes that have struck China in the new millennium. The following is a brief account of the 1556 event and of some of the more destructive earthquakes since 1900

Epicenters of historical earthquakes in China 900 A.D to 2000

China's Seismic ZonesCollision of India with the Asian mainland during the earliest Eocene (~50 Ma) has resulted in the growth of the world's largest orogenic belt, the Himalayas, and the associated Tibetan plateau. The seimotectonic tectonic evolution of China is characterized by the merger of several microcontinents throughout the entire Phanerozoic (e.g. Zhang et al., 1984; Hendrix and Davis, 2001).The collision and associated convergence and extension has created 64 major tectonic zones in China, which can be subdivided into a smaller number of tectonic "regions" (Zhang et al.,1984; Yin and Nie,1996. The eartquake (with a magnitude reported in the literature as ranging from 7.5 to 8.0), struck at 3:42 a.m. in the early morning hours of July 28, the worst time when the city was asleep. What made matters worse, was the fact that this city is located in the center of an area with major crustal faults on four sides and most structures had been built on unstable, alluvial soils. Only a few of its structures were earthquake-resistant. The earthquake, with its epicenter right on Tangshan, broke a five-mile section of a 25-mile long fault that passes through the city. Along the west side of this fault the land moved five feet northward in relation to the land on the east side. The east block tipped downward at the northern end of the break and upward toward the south end.

List of earthquake in china

Date September 27, 1290 September 25, 1303

Event 1290 Chihli earthquake[1] 1303 Shanxi earthquake[2]

Epicenter 41.5N 119.3ENingcheng County No data Shanxi, China 34.50N 109.30E Shaanxi, China

Magnitude

Deaths

Description

6.8 Ms

~100,000 Taiyuan and Pingyang were leveled to the ground. Deadliest earthquake of all time. The earthquake triggered a landslide that formed an artificial mud dam which blocked the Dadu River. Ten days later, this dam was breached resulting in a catastrophic mudslide flooding estimated to have taken the lives of over 100,000 people. 4th deadliest earthquake of all time.

8.0 ML 8.0 MW

200,000+ 820,000+

January 23, 1556 Shaanxi 1556 earthquake

June 1, 1786

1786 KangdingLuding earthquake[3][4]

No data Sichuan, China

7.75 ML

100,000+

December 16, 1920 May 22, 1927

1920 Haiyuan earthquake 1927 Gulang earthquake 1931 China earthquake

36.50N 105.70E Ningxia, China 37.39N 102.31E No data 39.7N 96.7E 32.0N 103.7E Sichuan, China No data No data 3704N11429EXingtai No data Yunnan, China No data 28.2N 104.0E Yunnan, China No data Liaoning, China No data Hebei, China

7.8 ML 7.6 Mw No data 7.6 Ms 7.5 MS No data No data 7.2 7.3 MS No data 6.8

234,117 40,900

December 25, 1932 August 25, 1933

1932 Changma earthquake 1933 Diexi earthquake 1950 Chayu earthquake[5] 1955 Kangding earthquake

275 9,000

March 8, 1966 January 4, 1970

1966 Xingtai earthquake[6] 1970 Tonghai earthquake 1973 Luhuo earthquake

8,064 15,621

May 10, 1974

1974 Zhaotong earthquake

20,000[7] Many lives were saved as a result of evacuations ordered by seismologists in China who predicted the quake the day before. 3rd deadliest earthquake of all time.

February 4, 1975 Haicheng 1975 earthquake July 28, 1976 August 16, 1976 1976 Tangshan earthquake

7.3 MS 7.5 MW 7.2 MS

1,328

242,419 41

1976 SongpanNo data Pingwu earthquake Sichuan, China

1980 Xinjiang earthquake January 23, 1981 Dawu 1981 earthquake February 3, 1996 Lijiang 1996 earthquake November 14, 2001 February 24, 2003 November 26, 2005 July 22, 2006 2001 Kunlun earthquake 2003 Bachu Earthquake 2005 Ruichang earthquake 2006 Yanjin earthquake

No data 6.0 M_B Yecheng, Xinjiang, China 30.93N 101.10E No data Yunnan, China 36.12N 90.54E Qinghai, China 39.61N 77.24E Xinjiang, China 29.657N 115.717E Jiangxi, China 27.992N 104.215E Yunnan, China 6.8 ML 7.0 MS 7.8 MW 6.3 MW 5.2 to 5.7MS 5.2 MW

No data 150+ 200 None 261 14 19 Damaged local railroad tracks including Neijiang-Kunming line. The deadliest earthquake in China since the 1976 Tangshan earthquake 32 years ago and the strongest in 58 years since the 1950 Chayu earthquake. The earthquake lasted three minutes and was felt as far away as Beijing and Shanghai some 1,500 and 1,700 km away where people were evacuated from office buildings as a precaution. Mianyang, Ngawa, Deyang, Guang yuan, and Chengdu suffered the most loss of lives. Most of the buildings that collapsed were in rural areas and did not adhere to building codes. At least 4.8 million people were rendered homeless.

May 12, 2008

2008 Sichuan earthquake

31.021N 103.367E Sichuan, China

7.9 MW

68,712

President Hu Jintao declared a national state of emergency 90 minutes after the quake. All highways into Wenchuan were damaged by the quake, delaying the arrival of relief troops. Half of the wireless communications were lost in the entire Sichuan Province. The earthquake occurred three months prior to the opening of the 2008 Summer Olympics hosted in China for the first time. None of the Olympic venues were damaged but the torch relay route was changed and a minute's silence was observed. The Chinese government announced RMB 1 trillion ($146.5 billion USD) to be spent on rebuilding the area over a period of three years.

August 30, 2008 August 19 to September 3, 2008

2008 Panzhihua earthquake 2008 Yingjiang earthquakes

26.2N 101.9E Sichuan, China 24.9N 97.8E Yunnan, China 43.3N 80.9E Xinjiang, China

5.7 MW

41

4.1 to 5.9MS

5

January 25, 2009 Xinjiang 2009 earthquake

5.0 MW

None

April 14, 2010 March 10, 2011

2010 Yushu earthquake 2011 Yunnan earthquake

33.3N 96.7E Qinghai province, China 24.710N 97.994E Yingjiang County, Yunnan, China

6.9 MW

2,698

5.4 MW

25+

1290 Chihli earthquake

The 1290 Chihli earthquake occurred on 27 September with an epicenter near Ningcheng, Inner Mongolia. The earthquake had an estimated magnitude of 6.8 and a maximum felt intensity of IX (violent) on the mercalli intensity scale. It is estimated that about 100,000 people were killed. Damage The earthquake destroyed 480 storehouses and countless houses in Ningcheng. Changping, Hejian, Renqiu, Xiongxian, Baoding, Yixian and Baixiang were also affected.It severely damaged the Fengguo Temple in Yixian.

1927 Gulang earthquake

Tectonic setting of the Tibetan Plateau showing main fault zonesThe 1927 Gulang earthquake occurred at 6:32 a.m. on 22 May (22:32 UTC on 21 May). This 7.6 magnitude event had an epicenter near Gulang, Gansu in China. There were more than 40,900 casualties. It was felt up to 700 km away. Geology The continental collision between the Indian Plate and the Eurasian Plate has formed the Himalayas and the large uplifted area of the Tibetan Plateau. The northeastern part of Tibet is affected by the eastward lateral spreading of the Tibetan Plateau. This spreading is accommodated by a series of sinistral (left-lateral) strike-slip faults, including the Atyn Tagh, Haiuyan, Kunlun and Xianshuihe faults, combined with thrusting on the Longmenshan fault. The earthquake ruptured the complex thrust fault system in the Qilian Mountains transpressional zone, formed at a restraining bend on the Haiyuan fault. Another segment of the Haiyuan fault was responsible for the 1920 Haiyuan earthquake. Damage In the area of greatest intensity, all cave dwellings and 90% of houses were destroyed. In Gulang, almost the only thing left standing was a 20 m long section of the city walls and some decorated archways. In Gulang county 4,000 people and 30,000 domestic animals were killed. In Wuwei, most of the city walls collapsed as did many temples, towers and civilian houses, 35,000 people and 200,000 horses and oxen were killed. In the area around Yongchang many primary schools, forts, stockaded villages and temples were destroyed, killing 809 people. In Shandan County more than 5,800 houses were destroyed and many cave dwellings collapsed, leaving 886 people dead. The ground was extensively fissured, with fissures up to 14 km in length, 613 m wide and 7 m deep. A large landslide at Dongchuan buried several villages and blocked the road for a year. Characteristics The magnitude of this earthquake has been variously calculated as 7.6 on the moment magnitude scale and 8.08.3 on the surface wave magnitude scale.[1] The surface rupture caused by the earthquake was 23 km long

1931 Fuyun earthquake

The 1931 Fuyun earthquake occurred on August 10, 1931 at 21:18 UTC. The epicenter was near Fuyun County of northern Xinjiang, China. It was a Mw 8.0 earthquake and had a surface rupture of 171 km[with a maximal horizontal displacement of 14 m along the Koktokay-Ertai fault zone. The Koktokay-Ertai fault has a slip rate of 42 mm per year.The rupture of this earthquake was caused by right-lateral strike-slip movement with normal component. The rupture is well preserved and becomes one of the main features of the Koktokay National Geopark located in Koktokay.

1950 Medog earthquake

The 1950 Medog earthquake, occurred on August 15, 1950, and had a magnitude of 8.6. The epicentre was actually located near Rima, in Tibet, China. However, the earthquake was destructive in both Assam and Tibet, and 1,526 people were killed. It was the 6th largest earthquake of the 20th century. It is also the largest known earthquake to have not been caused by an oceanic subduction. Instead, this quake was caused by two continental plates converging.

The Great China Earthquake of 1556The worse natural disaster in recorded history - at least in terms of lives lost - was caused by an earthquake in Hausien, in the Shaanxi Province of China in the morning of 23 January 1556. In Chinese historical record, this event is often referred as the "Jiajing Great Earthquake" because it occurred during the reign of Emperor Jiajing of the Ming dynasty. The "Shaanxi Earthquake" as it became later known, had an estimated magnitude ranging from 8.0 to 8.3 on the Richter scale (final assigned Moment Magnitude of 8), and had an estimated intensity of XI on the Modified Mercalli scale. Its epicenter was near Mount Hua in Shaanxi, close to present day Weinan city. The earthquake was responsible for the devastation of 98 counties and eight provinces in Central China, but particularly destructive in the Province of Shaanxi. The destruction extended over an area of 500 miles. In some of the counties, the average death toll was estimated to be about 60 percent of the population. According to historical records, a total of 830,000 people lost their lives, most from the collapse of poorly constructed houses and of Loess cave dwellings. Destructive Earthquakes in China in the 20th Century in relation to the most recent earthquake of May 12, 2008 (modified graphic of Western Australia Un.)

1970 Tonghai earthquake

Date Magnitude Depth

4 January 1970 7.5 Msd 13 kilometres (8 mi)

Countries or regions China Total damage Casualties Between US$5 to $25 million At least 15,621 dead

The 1970 Tonghai earthquake occurred on 4 January 1970 in Tonghai, China. The rupture originated on the local Yunnan Provinces Red River fault, which had not experienced an earthquake above magnitude 7 since 1700. The earthquake had a magnitude of 7.7 and killed at least 15,000 people, making it one of the deadliest in the history of China. The tremor caused between US$5 to $25 million in damage. felt over an area of 8,781 km (5,456 miles). In Hanoi, North Vietnam, almost 483 km (300 miles) from the epicenter, victims left their homes as the rupture rumbled through the city. Occurring during the height of the Cultural Revolution, it was not widely publicized by the Chinese government for well over a decade. The amount of aid and finances distributed was described by the Beijing Morning Post as "pathetically small". Much of the aid provided to survivors was in "spiritual" form, including Mao Zedong badges and condolence letters.

Nevertheless, the earthquake was among the first to be studied over a long term by the Chinese government. It was cited as one of the reasons behind creating the largest earthquake monitoring system in China, 25 years later.

Background and tectonics Yunnan Province, the epicentral region, has endured many earthquakes, and is one of the most seismically active provinces in China. The earliest earthquake recorded there was in the 9th century; however, moderate to strong ones have been observed since the 15th century. Since the 9th century, 32 earthquakes with a magnitude of 7 or greater have occurred in the province. Shallow strike-slip faulting is a characteristic of Yunnan quakes. Earthquakes in the southwestern part of this province, like the 1970 Tonghai event, occur less often than the provincial average. The Red River fault, the fault line on which this quake is alleged to have occurred, has lacked seismological activity as a whole. Red River temblors generally rise at high angles, as shown in a 1962 Ministry of Geology report. Marking in sedimentary rocks indicate that several large earthquakes formed on the fault during the Pleistocene and Holocene epochs. Until this quake, no earthquake above magnitude 7.0 on the Richter scale had occurred on this fault since about 1700, and the fault was believed to be "dead". Since the 1970 Tonghai rupture, it is believed that the Red River fault is instead experiencing a long seismic gap similar to that of the Japan Median Tectonic Line, on which no major temblor has formed since 700 but produced massive ones during the Holocene epoch. The epicenter of the quake was about 121 km (75 miles) southwest of Kunming, a city of about one million people at the time, and 97 km (60 miles) northwest of Gejiu (Kokiu), which has a population of 180,000; this area was mainly a tobacco-growing region. Effects of the rupture were felt over an area of 8,781 km (5,456 miles). In Hanoi, North Vietnam, almost 483 km (300 miles) from the epicenter, victims left their homes as the rupture rumbled through the city. The earthquake measured 7.7 on the Richter scale. It killed 15,621 people, making it the third deadliest in China during the 20th century and injured an additional 26,783. The tremor caused between US$5 to $25 million in damage. A Reuters news report, the only one in the immediate aftermath, mentioned the recording of a "severe" quake by Hong Kong's Royal Observatory and cited an unconfirmed report that it might have destroyed part of Kunming. It caused 50 km (31 miles) of visible surface faulting on the Tonghai Fault. There was a maximum horizontal offset of 2.5 m (8 ft) and vertical offset of about 0.5 m (1.5 ft). As a result of inversion techniques, scientists were able to decide that several events comprised the surface faulting. This further confirmed that the earthquake, along with a later earthquake in Yunnan Province in 1973, corresponded to a fault within the area.

The Haicheng Earthquake of February 4, 1975On February 4, 1975, Haicheng, a town with about 100,000 inhabitants in the Liaoning Province of northeast China, was struck by a 7.3 magnitude earthquake. As early as 1970, the State Seismological Bureau, had identified the Liaoning Province as an area of high earthquake risk. Six months before the earthquake, there had been a series of smaller quakes in the region which intensified on February 3rd. Based on studies of such precursor events and on unusual behavior exhibited by animals, a warning was issued by local authorities on February 3rd and in the early morning of February 4th.Thus, when the earthquake struck at 7:36 p.m. that evening of February 4, there were few lives lost as most inhabitants had evacuated to safer places. The death toll was relatively smaller than what could have been without the warning. Only 1,328 people lost their lives. However property damage was high.

The Tangshan Earthquake of July 28, 1976No other earthquake in this century has been as catastrophic or has claimed as many lives as the earthquake that struck the city of Tangshan in Northern China on July 28, 1976 (27 July 1976 local date). Tangshan, a thriving industrial city with one million inhabitants, is located in the Province of Hebei, about 95 miles east and slightly south of Beijing and about 280 miles southwest of Haicheng - where in the previous year another very destructive earthquake had occurred. Although the region had experienced moderate seismic activity in the past, there were no foreshocks this time, and no warning.

Complete Destruction of the City of Tangshan by the July 28, 1976 Earthquake Ground motions lasted for about 90 seconds and, during this time interval, about 90 percent of the houses and buildings in Tangshan collapsed. Over a four-by-five mile area the devastation of the city was nearly total. The force of the ground motions were so strong that people reported being thrown in the air. Within seconds, thousands died. Property destruction was unbelievable. Bridges, railroads, homes, factories were completely leveled. In the harbor city of Tientsin, 60 miles to the southwest, and in Beijing to the west, the strong ground motions forced thousands of frightened people into the streets seeking refuge from the aftershocks. The extent of the destruction and number of deaths in Tangshan and elsewhere in the region has been uncertain. According to official reports a total of 242,769 people died and

169,851 were severely injured. However, based on the density of population, it was fairly accurately estimated that there were at least 655,000 people dead and 780,000 injured. These figures make the 1976 Tangshan earthquake, the second worse earthquake in recorded history. The most destructive earthquake ever, as reported earlier, occurred in 1556. Since 1976 the city of Tangshan has been growing and its population has increased by more than 50 percent. A number of new structures have been built, including high rise structures like the Phoenix Hotel with a height of 112 meters. Although most stuctures built since 1976 have been designed to be earthquake resistant and in accordance to revised seismic construction codes, it is still uncertain what damage could be inflicted on the city of Tangshan when another stong earthquake strikes again in the future.

2000 Yunnan earthquake

Date Magnitude Epicenter Countries or regions Casualties

January 14, 2000 Mw 5.9 (USGS) 253625N 1010347E25.607N 101.063E China 7 killed, 2,528 injured, around 92,479 left homeless

The 2000 Yunnan earthquake occurred on January 14 2000, at 23:37 UTC, in Yunnan, China. The earthquake killed 7 people, and caused much damage in central Yunnan Province. The quake was moderate, with a magnitude of 5.9, however it left 2,528 injured, 92,479 homeless and destroyed over 41,000 homes. It was preceded by a magnitude 5.5 foreshock at 22:09, and a 4.9 magnitude earthquake occurred in the same area on 26 January.

2006 Yanjin earthquake

Date Magnitude Depth

22 July 2006 5.2 Mw 10.0 km 275931N 1041254E27.992N

Epicenter

104.215E (Yanjin County, Zhaotong, Yunnan)

Countries or regions Casualties

China At least 19

The 2006 Yanjin earthquake was a magnitude 5.2 earthquake in southwestern China. It occurred on July 22, 2006, at 01:10 UTC (09:10 local time). Seismologists have placed the epicentre at 275931N 1041254E27.992N 104.215E / 27.992; 104.215, and its hypocenter at a depth of 10.0 km. This is 35 km WNW from Zhaotong city and 1740 km SW of Beijing, the capital city of China. The earthquake toppled at least 1400 houses and sent large boulders tumbling down the hillsides onto residential areas in the mountainous southern regions of the Yunnan province. Chinese officials have been reported as saying that the tremor killed 16 and injured 60 people in Yanjin County, and killed a further three and injured 46 more in nearby Daguan County. Railroad services in the region were halted by the quake, as the quake damaged the local railroad tracks, forcing officials to shut down service between Sichuan's Neijiang city and Yunnan's capital of Kunming. Yanjin County has a population of about 350,000.

2008 Yingjiang earthquakes

The 2008 Yingjiang Earthquakes were a series of major earthquakes ranging from surface wave magnitude (Ms) 4.1 to 5.9 that struck Yingjiang County, Yunnan province, China between August 19 (in UTC; August 20 local time) and September 3, 2008. It caused 5 deaths, 21 serious injuries, and RMB 2.7 billion in direct economic damage. USGS put the magnitude of the strongest one to Mw 6.0. Earthquake Details According to the China Earthquake Administration (CEA) and its subordinate China Earthquake Network Center (CENC), a Ms 5.0 earthquake struck Yingjiang County, Yunnan province, China on August 20, 2008 at 05:35:09 China Standard Time (CST - 2135 UTC, August 19, 2008). A CEA report published on September 17 described two additional strong quakes of Ms 4.9 and Ms 5.9 in the same area the following day; CENC's data base, on the other hand, did not include the earthquake of Ms 4.9 at 20:20 CST on August 21 as the CEA report described, but reveals additional ones after the date.

2009 Xinjiang earthquake

Date Magnitude Depth

25 January 2009 5.0 Mw 10 kilometres (6.2 mi) 4318N 8054E43.3N

Epicenter

80.9ECoordinates:8054E43.3N 80.9E

4318N

Countries or regions Total damage Casualties

China $US 3.1 million none

The 2009 Xinjiang earthquake is an earthquake that occurred in the Xinjiang Uygur Autonomous Region of the People's Republic of China. It occurred at 9:47 a.m in Qapqal on January 25, 2009.

LocationThe epicenter was at 43.3 degrees north latitude and 80.9 degrees east longitude at a depth of 10 km according to the China Earthquake Administration. The quake occurred 700 km from the regional capital Urumqi.

DamagesThe quake measured 5.0 on the Richter scale on Sunday. It has affected more than 4,500 people and caused house collapses and damages. In total, 4,549 people in the Xibe Autonomous County of Qapqal and Zhaosu County were affected. They have been relocated to schools, government buildings and tents, said a regional civil affairs department official. No casualties have been reported so far. A total of 198 houses collapsed and 2,928 were damaged. The direct economic loss was estimated at 21 million yuan ($US 3.1 million).

2010 Yushu earthquake

The 2010 Yushu earthquake struck on April 14, 2010, and registered a magnitude of 6.9Mw (USGS, EMSC) or 7.1Ms (CEA, CENC). It originated in Yushu, Qinghai, China, at 7:49 am local time. According to the Xinhua News Agency, 2,698 people have been confirmed dead, 270 missing, and 12,135 injured of which 1,434 are severely injured. The epicenter was located in Rima village, Upper Laxiu township of Yushu County in remote and rugged terrain, near the border of Tibet Autonomous Region. The epicenter is about 30 km from Gygu town or Jyekundo, the seat of Yushu County, and about 240 km from Qamdo. The epicenter was in a sparsely populated area on the Tibetan plateau that is regularly hit by earthquakes. Qinghai lies in the northeastern part of the Tibetan Plateau, which formed due to the ongoing collision of the Indian Plate with the Eurasian Plate. The main deformation in this area is crustal shortening, but there is also a component of left lateral strike-slip faulting on major westeast trending structures such as the Kunlun and Altyn Tagh fault systems that accommodate southeastward translation of the Tibetan area. The earthquake occurred on the Yushu fault, about 300 kilometres (186 mi) south of the Kunlun fault. The Yushu fault forms part of the Yushu-Garz-Xianshuihe fault zone one of the most active fault zones in eastern Tibet. In history, many earthquakes greater than magnitude 7 have occurred in the Xianshuihe fault zone, for example, the magnitude 7.25 earthquake in the Luhuo area on March 24, 1923, and the Ms 7.6 earthquake on February 6, 1973 in Luhuo. Almost all sections of the Xianshuihe fault zone have produced strong earthquakes in records, except the sections of Yushu and Shimian. However, a trace of a strong earthquake occurred about 16,000 or 17,000 years ago has been found in Shimian. Hence, the Shimian section of the Xianshuihe fault zone is speculated to be currently locked and have the possibility of producing a strong earthquake in the future.

DamageIn Qinghai, building damage was reported with no casualties in the counties of Zadoi, Nangqn, and Qumarleb of Yushu Prefecture. At least 11 schools were destroyed in the earthquake. Over 85% of buildings in Gyegu, mostly of wood-earth construction, were destroyed, leaving hundreds trapped and thousands homeless. A vocational school collapsed and trapped many students. Power outage was also reported in Gygu. In Sichuan, strong shaking could be felt in the counties of Srx, Dg, and Baiy, Garz Tibetan Autonomous Prefecture. Road damage was reported in Srx County. Due to the rough terrain and the fact that landslides have destroyed the local infrastructure, the initial rescue operations were undertaken by the People's Armed Police and People's Liberation Army soldiers of Lanzhou Military Region. The Qinghai provincial government said in a public statement that five thousand tents, 100,000 thick, cotton coats, and heavy blankets were being sent to help survivors cope with the strong winds and near-freezing temperatures of around 6 C (43 F). The Yushu Batang Airport was re-opened at noon on Wednesday, April 14, and the first flight with personnel and supplies of the China International Earthquake Rescue Team landed there at 8 pm.

The Changu Dam, located on the Batang River; a right tributary of the upper Yangtze River some 15 km upstream from the Yushu County seat was damaged by the earthquake. Chinese language news reports as translated in a press release from the International Rivers stated that it is "at the risk of collapse at any time."