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

China Standard Time The time in China follows a single standard time offset of UTC+08:00 (eight hours ahead of Coordinated Universal Time), even though the country spans almost five geographical time zones. The official national standard time is called ''Beijing Tim ...

Hainan Tibetan Autonomous Prefecture Hainan Tibetan Autonomous Prefecture, formerly known as Tsolho Tibetan Autonomous Prefecture (; ), is an autonomous prefecture of Northeastern Qinghai Province in Western China. The prefecture has an area of and its seat is located in Gonghe C ...

Qinghai Province Qinghai (; alternately romanized as Tsinghai, Ch'inghai), also known as Kokonor, is a landlocked province in the northwest of the People's Republic of China. It is the fourth largest province of China by area and has the third smallest pop ...

. 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 (; symbol: ¥; ISO code: CNY; abbreviation: RMB) is the official currency of the People's Republic of China and one of the world's most traded currencies, ranking as the fifth most traded currency in the world as of April 202 ...

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

Gonghe County Gonghe County (; ), 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. Demographics In 2006, 55% of the population were Tibetans, with ...

, 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 "wate ...

d a blind thrust fault 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 affects the Earth's surface. Surface rupture is opposed by buried rupture, where the ...

. 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 History of Qinghai Buried rupture earthquakes Earthquakes in Tibet 1990 in China

Damage

Characteristics

See also

References