From March 8 to 29, 1966, a number of earthquakes of magnitude 6 to 7.2 occurred consecutively. The first earthquake occurred east of Longyao County in the Xingtai area, with a magnitude of 6.8, and since then, there have been five more magnitude 6 earthquakes, the largest being a magnitude 7.2 earthquake that occurred southeast of Ningjin County on the 22nd. Due to the influence of loose soil, high water table and ancient river channels in the affected areas, the earthquakes caused serious damage and loss, and the scope of damage was large. 142 counties and cities were affected by the 6.8 magnitude earthquake, and the damage caused by the 7.2 magnitude earthquake included 136 counties and cities. The felt range was as far north as Duolun in Inner Mongolia, as far east as Yantai, as far south as Nanjing, and as far west as Tongchuan and other vast areas. The earthquake *** caused 8,182 deaths, 51,395 injuries, destroyed more than 4 million houses and damaged 86 bridges. Accidental fires occurred in the disaster area*** in 115 cases, killing 16 people, injuring 26, and destroying 153 improvised houses. More than 300 landslides occurred in the mountainous areas of western Xingtai and the areas around Jingfu and Wuan, and 22 fires were caused by landslide flying rocks, burning 80 hectares of mountains. Ground cracks, sand, water phenomenon is common, intermittent extension of dozens of kilometers to several kilometers, the widest cracks up to 2m, wells, water rising or overflowing and so on is very common. Several bridges on the Busan River were severely damaged, Aixinzhuang Bridge deck to the south, and the abutment staggered 1.8m, resulting in traffic disruption. The quake affected a wide range of areas, with generators dropping out in Tianjin and Zhuozhou, Hebei, causing brief power outages, and high levels of damage west of Shijiazhuang and in Xiyang, Shanxi.
(2) Yunnan Tonghai Earthquake
At 1:00 a.m. on January 5, 1970, at 1:03:37 a.m., a major earthquake of magnitude 7.8 occurred in the vicinity of Wujie Village, Gao Daxiang Township, Tonghai County, Yunnan Province, at a depth of about 13km, with an epicenter intensity of 10 degrees strong. The affected areas included Yuxi, Tonghai, Moth Mountain and Huaning, etc. The earthquake damage involved an area of 8,881km2, of which 2,400km2 was the hardest-hit area. The total number of deaths was 15,621, the number of dead and dying households was 836, the number of serious injuries was 5,648, 261 orphans were left behind, and 166,117 houses were completely collapsed. Extreme earthquake area for the Tonghai, Jianshui, Eshan three-county junction, that is, within 824k square meters on both sides of the Qujiang River, the three counties of the quake deaths as high as 14,917 people, of which Jianshui County quake deaths of 7,479 people, Tonghai County quake deaths of 4,426 people, Eshan County quake deaths of 3,012 people.
(3) Yunnan Daguan Earthquake
In May 11, 1974, a 7.1-magnitude earthquake occurred in Daguan. The felt area was about 400,000k㎡. The earthquake caused 1,423 deaths and more than 1,600 injuries; more than 66,000 houses were damaged, of which more than 28,000 collapsed, and the area of the house destruction zone was about 2,300k㎡. The wooden frame of the wooden structure houses in the extreme earthquake area was not damaged, while the earth and stone walls collapsed, and most of the earth beam houses and stone beam houses built of burrstone masonry collapsed or fell flat. The earthquake also caused landslides and cracks in the ground, destroying roads, farmland, and waterways, and burying villages and houses. The leading edge of the largest landslide reached the other side of the creek, forming a dam about 30 meters high and blocking the water into a lake.
(4) Liaoning Haicheng Earthquake
On February 4, 1975, a magnitude 7.3 earthquake occurred in Haicheng. The area of the extreme earthquake zone was 760k㎡. This earthquake occurred in a densely populated and industrially developed area, and was the largest earthquake ever recorded in the area. Due to the earthquake department of our country made a prediction of this earthquake, the local government took strong earthquake prevention measures in time, so that the earthquake disaster was greatly reduced, in addition to housing buildings and other engineering structures suffered varying degrees of damage and loss, the earthquake most of the people evacuated their houses, the casualties were greatly reduced, the total number of casualties was 29,579, accounting for 0.32% of the total population, of which the deaths of 2,041 people The total number of casualties was 29,579, accounting for 0.32% of the total population, with 2,041 deaths. The earthquake caused the collapse of town houses and damage of about 5 million square meters, public **** facilities damaged 1.65 million square meters, rural housing destroyed 17.4 million square meters, urban and rural transportation, water conservancy facilities destroyed 2937, a variety of equipment, materials also suffered serious losses, total losses of about 810 million yuan. Ground sand blasting holes as large as 2.5m in diameter. there is an earthquake fracture, about 5.5km long, - the widest part of the seam zone up to 40m. yingkou city damage to the area accounted for 53.1% of the city's total area. Sea & earthquake of successful forecasting will be greatly reduced losses, it is speculated that, if there is no forecast, casualties will reach about 150,000 people, economic losses will be more than 5 billion yuan.
(5) Yunnan Longling earthquake
May 29, 1976, Longling County in western Yunnan has occurred two strong earthquake, the first occurred at 20:23:18, magnitude 7.3, the second occurred at 22:0:23, magnitude 7.4. The earthquakes were of the cluster type. Aftershock activity was frequent and intense. Two extreme seismic zones appeared in each of the earthquakes. From May 29 to the end of that year*** 2,477 earthquakes of magnitude 3 or higher were recorded, of which 19 were of magnitude 4.7 to 5.9 and one each of magnitude 6.2, 7.3 and 7.4. The earthquake caused varying degrees of damage to nine counties in Baoshan, Lincang and Dehong Dai and Jingpo Autonomous Prefectures in Yunnan Province, with 98 deaths, 451 serious injuries and 1991 minor injuries, and 420,000 collapsed and damaged houses. The affected area was about 1,883k square meters. Earthquake-induced landslides also caused serious losses. Landslides destroyed 180 farmhouses, destroyed nearly 3900 hectares of paddy fields, pastures, forest tea gardens, damaged 1126 channels, destroyed a hydroelectric power station with an installed capacity of 240kW and three hydroelectric power stations with less than 20kW. Destroyed 185km of roads, landslides amounted to 780,000m? Longling earthquake was preceded by medium-term and short-range forecasts, and appropriate anti-seismic measures were taken before the earthquake. Shallow avalanche landslides were typical of this earthquake.
(6) Hebei Tangshan Earthquake
A 7.8-magnitude earthquake occurred at 03:42:53 on July 28, 1976, in the city of Tangshan. The epicenter of the earthquake was located in the Tangshan city district, and the intensity of the epicenter reached 11 degrees (some say 10 degrees). This was a rare urban earthquake disaster in China's history. In a matter of moments (23 seconds), a city with a population of one million was reduced to rubble, 97% of the buildings on the ground and 55% of the production equipment were destroyed, and people's lives and property as well as national property suffered heavy losses. Beijing and Tianjin were severely affected by the earthquake, the earthquake damage area of more than 30,000k square meters, felt in 14 provinces, municipalities and autonomous regions, equivalent to 1/3 of the country's area. the earthquake occurred in the middle of the night, 80% of the people in the urban areas did not have time to react, buried under the rubble. Extreme earthquake area, including 47k square meters on the north and south sides of the Jingshan Railway, all the buildings in the area almost disappeared. An 8km-long, 30m-wide crack in the ground cut through walls, houses, roads and drains. The earthquake area and its surrounding areas, a large number of fissure zones, water spraying sand, blowouts, gravity collapse, rolling stone, slope collapse, landslide, foundation subsidence, rock cavern subsidence, as well as the collapse of the coal mine hollow area, and so on. Earthquake **** caused 242,000 people died, 164,000 people were seriously injured, 7,200 families all died, 4,204 people became orphans, only the Tangshan city area life-long disability of more than 1,700 people; destroyed 14.79 million square meters of public housing, collapsed 5.3 million rooms; direct economic losses of up to 5.4 billion yuan. The city's water supply, power supply, communications, transportation and other lifeline projects were all destroyed, all industrial and mining production was halted, all hospitals and medical facilities were destroyed. Seven passenger and freight cars and tanker trucks traveling during the earthquake were derailed. Two large highway bridges over the Ji-Canal and Luan River collapsed, cutting off highway transportation between Tangshan and Tianjin and Guanwai. The urban water supply pipe network and water plant buildings, structures and water wells were severely damaged. Ground buildings and structures of Kailuan Coal Mine collapsed or were severely damaged, and underground production was interrupted, with nearly 10,000 workers trapped underground. Tangshan Iron and Steel Company was severely damaged and forced to stop production, with steel and iron solidifying in the furnace chamber. The dams of three large reservoirs and two medium-sized reservoirs slipped and cracked, and the wave walls collapsed. 240 out of 410 small reservoirs were damaged by the earthquake. 60,000 wells were silted up and sandy, and the pipes of the wells were wrongly broken, which accounted for 67% of the total number of wells. More than 33,000 hectares of arable land were sand-pressed and 47,000 hectares were flooded by salty water. More than 55,000 agricultural implements were destroyed. It killed 36,000 large livestock and 442,000 pigs. The environmental health of Tangshan City and nearby hard-hit counties deteriorated sharply, and intestinal infectious disease was particularly prominent.
(7) Sichuan Songpan and Pingwu Earthquake
August 16, 1976, a 7.2-magnitude earthquake occurred between Songpan and Pingwu. The earthquake was of the cluster type, and the main quake was followed by a 6.7-magnitude quake on the 22nd and a 7.2-magnitude quake on the 23rd. The earthquake was felt over a wide area, from Gaotai in Gansu in the west to Kunming in the south, from Hohhot in the north to Changsha in the east, with a maximum radius of 1,150 km. Heavy rainfall after the quake resulted in landslides, rockfalls, mudslides, etc., which led to the destruction of farmland, roads, riverbeds, etc., and disruption of communications. More than 100,000 hectares of arable land were destroyed, with grain losses amounting to 5 million kilograms and more than 2,000 head of livestock killed. The earthquake occurred in a sparsely populated mountainous area, and since it was predicted before the earthquake and evacuation measures were taken, the number of casualties was only 800, of which more than 600 were minor injuries. Most were caused by secondary disasters such as mudslides, landslides and tumbling rocks after the quake.
(8) Hebei Shangyi Earthquake
A 6.2-magnitude earthquake struck the area east of Shangyi, Hebei Province, at 11:50 p.m. on Jan. 10, 1998, causing serious casualties and economic losses, making it the worst earthquake disaster in China that year. The earthquake affected 19 townships in Zhangbei, Shangyi and Wanquan counties, with a population of nearly 170,000 in the affected areas. In the earthquake, 49 people died and 11,439 were injured, including 362 seriously, accounting for 83.9% of the national total that year. Due to the unreasonable structure and location of the local residents' houses, the construction quality and anti-seismic performance of the houses were not strong, and some of the houses themselves were already dangerous, therefore, the houses were more seriously damaged, and the damaged area reached more than 6.5 million square meters, of which 1.754 million square meters were completely destroyed. The direct economic losses of the earthquake amounted to 794 million yuan, accounting for 44.6% of the total output value of the year. With the county neighboring Shanxi Datong Gao Tian County suffered direct economic losses also reached 5.879 million yuan.
(9) Sichuan Wenchuan Earthquake
A powerful 8.0-magnitude earthquake struck Wenchuan, Sichuan (Yingxiu Township) at 14:28 on May 12, 2008, at a depth of about 14km, with the release of the main energy of the earthquake being completed within a minute or so. So far, more than 60,000 aftershocks have occurred and will continue for quite a long time, with the largest aftershock reaching magnitude 6.4. These aftershocks are mainly distributed in the north-central section of the Longmenshan fault zone from Yingxiu town to Qingchuan county, forming a 300-km-long aftershock zone, making this earthquake a huge earthquake with low rate, long period and high intensity. This earthquake was characterized by slow accumulation of energy, long recurrence cycle, large area of influence, high intensity of damage, and heavy secondary disasters, which caused extremely huge casualties and economic losses. The most fundamental source of power for this huge earthquake was still the accumulation and release of energy generated by the relative movement between the Tibetan Plateau and the South China landmass on the rift zone. The fault zone is the boundary tectonic zone between the Tibetan Plateau and the South China Massif, which has undergone a long period of geological evolution and has a very complex geological structure and evolutionary history. The Indian continent pushed northward, forming the "roof of the world" Tibetan Plateau, whose average altitude is more than 5000m, and the thickness of the underground crust reaches 60~70km, which is 20~30km more than that of the 40km thick crust in Sichuan Basin. The crustal material of the plateau can only expand eastward and northward, leading to the proliferation of the Tibetan Plateau in these two directions. Due to the blockage of the Sichuan Basin, the Longmen Mountain Range, which is nearly 500 kilometers long and 40 to 50 kilometers wide, with a north-east direction, was formed in the border area between the eastern part of the Qinghai-Tibet Plateau and the Sichuan Basin, starting from Luding and Tianquan in the south, and extending to Guangyuan and Mianxian County of Shaanxi Province in the north. The important rock unit that constitutes the Longmen Mountain range is the ancient miscellaneous rock body, this kind of rock resistance to damage and fracture strength is particularly large, can accumulate a lot of energy in the instant release to form a strong earthquake.
The quake was the result of the Yingxiu_Beichuan rupture within the Longmenshan fault zone. In just a minute or so after the earthquake, a 300-km-long and 30-km-deep rupture was formed in the deep rocks of the earth's crust, of which more than 200 km was exposed on the surface, forming a surface rupture zone along the Yingxiu-Beichuan rupture. In addition, more than 60 km of rupture occurred in the Dujiangyan-Jiangyou rupture on the border between Longmen Mountain and Chengdu Plain. The seismic surface rupture zone extends from the southwest to the northeast, and the rupture face is tilted to the northwest. Relative to the Sichuan Basin, the Longmenshan Mountains have both upward and northeasterly movements along the surface rupture zone, with the maximum vertical and horizontal misalignments of 5m and 4.8m, respectively, and an average misalignment of up to 2m along the entire rupture zone. Because the energy of the earthquake was mainly released along the rupture, causing earthquake damage in the direction perpendicular to the rupture attenuation is very fast, so the earthquake did not cause much damage to the Chengdu Plain. The relative decline in the Sichuan Basin, the decline in the Anxian and Dujiangyan area along the front of the Longmen Mountains was the largest, amounting to 30~60cm, and rapidly becoming smaller to the east, to the Chongqing area instead showed a rise of several millimeters, but with a large margin of error. The earthquake also caused surface deformation over a large area, and post-earthquake GPS observations showed that Longmenshan and the Sichuan Basin rose substantially, in addition to substantial phreatic motion in the horizontal direction. This large-scale surface deformation image is the elastic transient deformation caused by the earthquake, which will gradually stop and return to the original stable motion state with time. The ground projection of the rupture start point of this earthquake corresponds to Wenchuan County, so it is called the "5J2" Wenchuan earthquake.
There are four reasons for the devastation of Beichuan County: the Yingxiu-Beichuan earthquake rupture passed through the entire county; the earthquake rupture displacement near the county was large, and the energy released by the earthquake here was also large; the county was located on top of loose piles on the river bank, and the damage was exacerbated by site effects and foundation failure; and the disaster was compounded by massive landslides and rockfalls (which buried a large number of houses). The slow sliding rate of the Longmenshan Fracture Zone has also led to the lengthening of the recurrence period of strong earthquakes, and it is estimated that the recurrence interval of strong earthquakes of magnitude 8 in the Longmenshan Fracture Zone is at least 3,000 to 5,000 years or more, which is why there have been no strong earthquakes on the Longmenshan Fracture Zone in the thousands of years of historical records (according to Zhang Peizhen, director of the Institute of Geology of the China Seismological Bureau, and the head of the North-South Belt Seismic Tectonics Study Group of the National Wenchuan Earthquake Expert Committee). Zhang Peizhen's detailed explanation to the members of the Standing Committee of the National People's Congress on June 26, 2008).
May 12, 2008 Wenchuan 8.0 magnitude earthquake occurred at 14:28, Mianzhu People's Hospital inpatient building (seven-story cast-in-place reinforced concrete frame structure) seventh floor operating room door in the Wenchuan earthquake there is a section of the surveillance video, the hospital from the hospital's seventh-floor operating room door hangers of the movement of the situation is from 14:27 hours 18 seconds (may be a clock error), to the 35 minutes to the end, lasted 7 minutes and 42 seconds, the most powerful vibration is 27 minutes and 20 seconds to 28 minutes and 34 seconds, 74 seconds within the X vibration, y vibration, clockwise rotation, counterclockwise rotation. So the Wenchuan earthquake was very severe.
According to the morning of June 24, 2008, Hui Liangyu, Vice Premier of the State Council and Deputy Commander-in-Chief of the State Council General Command of Earthquake Relief and Disaster Relief, on behalf of the State Council and the State Council General Command of Earthquake Relief and Disaster Relief, reported to the Standing Committee of the National People's Congress on the previous stage of the earthquake relief and rescue of the Wenchuan Earthquake in Sichuan, said that the earthquake of 8 magnitude on the Richter Scale which occurred in Wenchuan County, Sichuan Province, on May 12 was the most destructive and most extensive earthquake in the world since the founding of the People's Republic of China. The earthquake was the most destructive, the most extensive and the most difficult earthquake disaster to rescue. The total area of the disaster area of 440,000k square meters, involving Sichuan, Gansu, Shaanxi, Chongqing and other provinces (districts, municipalities) in 417 counties, 4656 townships, 47,789 villages, 7,789,100 collapsed houses, 24,590,000 damaged houses, the area of the worst-hit areas amounted to 125,000k square meters, the affected population of 46,240,000 people,
Wenchuan County, Sichuan Province, of which the area of the disaster area amounted to 280,000k square meters, the affected population of 29.83 million; secondary disasters, and the disaster area of the disaster area amounted to 2,983 million. 29.83 million; secondary disasters, landslides, landslides, mudslides occur frequently, blocking the formation of larger river weir 35, 2473 reservoirs once appeared in varying degrees of danger; 6443 industrial enterprises above designated size (of which Sichuan $ 10) once stopped production, the loss of livestock and poultry due to the disaster amounted to 44.62 million head (only).
As of 'September 4, 2008, according to statistics, this Wenchuan earthquake caused direct economic losses of 845.1 billion yuan RMB. Sichuan was the worst hit, accounting for 91.3 percent of the total losses, Gansu for 5.8 percent, and Shaanxi for 2.9 percent. The National Bureau of Statistics (NBS) categorized the loss indicators into three groups, the first being casualties, the second being property damage, and the third being damage to the natural environment. Among the property losses, the loss of houses is very large, with the loss of private houses (of which more than 18,000 houses in Dujiangyan were severely damaged) and urban housing accounting for 27.4% of the total losses, including the loss of schools, hospitals, and other non-residential housing accounting for 20.4% of the total losses, and the loss of infrastructure, roads, bridges, and other urban infrastructure, accounting for 21.9% of the total losses.
These three categories of losses are relatively large, accounting for more than 70 percent of the total.
As of May 7, 2009, according to statistics, the Wenchuan earthquake *** caused 69,225 people were killed, 17,939 people are missing, 374,640 people were injured, 68,712 people were killed in Sichuan province, 17,921 people are missing, of which 5,335 students were killed or missing.
(10) Qinghai Yushu Earthquake
At 5:39 a.m. on April 14, 2010, a 4.7-magnitude earthquake occurred in Yushu County, Yushu Tibetan Autonomous Prefecture, Qinghai Province, at a depth of about 6km, and at 7:49 a.m. a 7.1-magnitude earthquake occurred, at a depth of about Mkm, and at 13:00 a.m. ****17 aftershocks of magnitude 3 or higher occurred, of which 10 were of 3.0-3.9 magnitude. The first 4.7-magnitude earthquake can be regarded as the first 4.7-magnitude earthquake, and the depth of the earthquake was about Mkm. The first 4.7-magnitude earthquake could be seen as an early warning of the second 7.1-magnitude quake, but because the 4.7-magnitude quake was short-lived and weak, and occurred in the early hours of the morning, when most residents were still asleep, it was not detected. 5.7-magnitude earthquakes struck again at 10:29 a.m. on May 29, 2010, and the quake was not detected because it was so severe that it could not be felt. Because Yushu is in an economically underdeveloped area, most of them are earth (adobe brick) wood structure or brick structure (most of them are large hole bricks, originally large hole bricks can only build non-load-bearing partitions, and can not be used to build load-bearing walls) simple houses, seismic capacity is very poor, the amount of house collapses is larger.