The 1990 Gonghe earthquake occurred on April 26 at 17:37

China Standard Time The time in China follows a single standard UTC offset, time offset of UTC+08:00, where Beijing is located, even though the country spans five geographical time zones. It is the largest sovereign nation in the world that officially observes only ...

Hainan Tibetan Autonomous Prefecture Hainan Tibetan Autonomous Prefecture, formerly known as Tsolho Tibetan Autonomous Prefecture ( zh, c=海南藏族自治州; ), is an autonomous prefecture of Northeastern Qinghai Province in Western China. The prefecture has an area of and its ...

Qinghai Province Qinghai is an inland province in Northwestern China. It is the largest province of China (excluding autonomous regions) by area and has the third smallest population. Its capital and largest city is Xining. Qinghai borders Gansu on the nort ...

. The mainshock had a surface wave magnitude of 7.0 and a moment magnitude of 6.5 . It was presaged by two foreshocks that struck merely seconds before the main earthquake. On the Mercalli intensity scale, the earthquake had a rating of IX (''Violent'').

Damage

At least 126 people died and 2,049 left wounded by the earthquake. Landslides and extensive destruction was reported in the area. Damage to properties was major, with 21,000 homes collapsing and another 66,800 damaged. The Longyangxia Reservoir about 60 km away from the earthquake experienced strong shaking which triggered landslides but its nearby power plant and dam were in normal working conditions. Total damage caused by the earthquake is estimated at 270 million

Chinese Yuan The renminbi ( ; currency symbol, symbol: Yen and yuan sign, ¥; ISO 4217, ISO code: CNY; abbreviation: RMB), also known as the Chinese yuan, is the official currency of the China, People's Republic of China. The renminbi is issued by the Peop ...

. In the zone with the highest intensity, IX, encompassing

Gonghe County Gonghe County ( zh, s=共和县; ), also known as Kungho, is a county of Qinghai Province, China under the administration of Hainan Prefecture. The seat of Gonghe County is in the town of Qabqa. Administrative divisions Gonghe County is made up ...

, all brick and adobe constructed houses were razed. About 320 wood-framed and mud-walled settlements were destroyed, the only 12 left standing suffered serious damage. Brick and concrete bungalows did not collapse but they were severely compromised after the earthquake. In zones with intensities VII and VIII, more homes collapsed, causing casualties. Some old houses in zone VI also collapsed.

Characteristics

The earthquake in the northeastern Tibetan Plateau according to seismologists,

rupture Rupture may refer to: General * Rupture (engineering), a failure of tough ductile materials loaded in tension Anatomy and medicine * Abdominal hernia, formerly referred to as "a rupture" * Achilles tendon rupture * Rupture of membranes, a "water ...

d a

blind thrust fault A thrust fault is a break in the Earth's crust, across which older rocks are pushed above younger rocks. Thrust geometry and nomenclature Reverse faults A thrust fault is a type of reverse fault that has a dip of 45 degrees or less. If ...

structure due to the absence of a

surface rupture In seismology, surface rupture (or ground rupture, or ground displacement) is the visible offset of the ground surface when an earthquake rupture along a Fault (geology), fault affects the Earth's surface. Surface rupture is opposed by buried rup ...

. Elements of both sinistral strike-slip and reverse components were detected during the co-seismic rupture, with the latter having a greater sense. The estimated length and width of the rupture is 37 km and 6 km respectively, with a slip of around 2.7 meters.

References

{{Earthquakes in China 1990 earthquakes 1990 disasters in China Hainan Tibetan Autonomous Prefecture Buried rupture earthquakes Earthquakes in Qinghai Earthquakes in Tibet 1990 in China April 1990 in China

Damage

Characteristics

See also

References