China Earthquake

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<p>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.</p> <p>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.</p> <p>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.</p> <p>Movement of plates in the world</p> <p>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.</p> <p>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</p> <p>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.</p> <p>Movement of plates in china region</p> <p>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.</p> <p>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"</p> <p>Seismic plates of china region</p> <p>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</p> <p>Epicenters of historical earthquakes in China 900 A.D to 2000</p> <p>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.</p> <p>List of earthquake in china</p> <p>Date September 27, 1290 September 25, 1303</p> <p>Event 1290 Chihli earthquake[1] 1303 Shanxi earthquake[2]</p> <p>Epicenter 41.5N 119.3ENingcheng County No data Shanxi, China 34.50N 109.30E Shaanxi, China</p> <p>Magnitude</p> <p>Deaths</p> <p>Description</p> <p>6.8 Ms</p> <p>~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.</p> <p>8.0 ML 8.0 MW</p> <p>200,000+ 820,000+</p> <p>January 23, 1556 Shaanxi 1556 earthquake</p> <p>June 1, 1786</p> <p>1786 KangdingLuding earthquake[3][4]</p> <p>No data Sichuan, China</p> <p>7.75 ML</p> <p>100,000+</p> <p>December 16, 1920 May 22, 1927</p> <p>1920 Haiyuan earthquake 1927 Gulang earthquake 1931 China earthquake</p> <p>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</p> <p>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</p> <p>234,117 40,900</p> <p>December 25, 1932 August 25, 1933</p> <p>1932 Changma earthquake 1933 Diexi earthquake 1950 Chayu earthquake[5] 1955 Kangding earthquake</p> <p>275 9,000</p> <p>March 8, 1966 January 4, 1970</p> <p>1966 Xingtai earthquake[6] 1970 Tonghai earthquake 1973 Luhuo earthquake</p> <p>8,064 15,621</p> <p>May 10, 1974</p> <p>1974 Zhaotong earthquake</p> <p>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.</p> <p>February 4, 1975 Haicheng 1975 earthquake July 28, 1976 August 16, 1976 1976 Tangshan earthquake</p> <p>7.3 MS 7.5 MW 7.2 MS</p> <p>1,328</p> <p>242,419 41</p> <p>1976 SongpanNo data Pingwu earthquake Sichuan, China</p> <p>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</p> <p>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</p> <p>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.</p> <p>May 12, 2008</p> <p>2008 Sichuan earthquake</p> <p>31.021N 103.367E Sichuan, China</p> <p>7.9 MW</p> <p>68,712</p> <p>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.</p> <p>August 30, 2008 August 19 to September 3, 2008</p> <p>2008 Panzhihua earthquake 2008 Yingjiang earthquakes</p> <p>26.2N 101.9E Sichuan, China 24.9N 97.8E Yunnan, China 43.3N 80.9E Xinjiang, China</p> <p>5.7 MW</p> <p>41</p> <p>4.1 to 5.9MS</p> <p>5</p> <p>January 25, 2009 Xinjiang 2009 earthquake</p> <p>5.0 MW</p> <p>None</p> <p>April 14, 2010 March 10, 2011</p> <p>2010 Yushu earthquake 2011 Yunnan earthquake</p> <p>33.3N 96.7E Qinghai province, China 24.710N 97.994E Yingjiang County, Yunnan, China</p> <p>6.9 MW</p> <p>2,698</p> <p>5.4 MW</p> <p>25+</p> <p>1290 Chihli earthquake</p> <p>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.</p> <p>1927 Gulang earthquake</p> <p>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 northe...</p>