USGS Eathquake Center

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Earthquake Details
Magnitude 7.8
Date-Time

* Monday, May 12, 2008 at 06:28:00 UTC
* Monday, May 12, 2008 at 02:28:00 PM at epicenter
* Time of Earthquake in other Time Zones

Location 31.099N, 103.279E
Depth 10 km (6.2 miles) set by location program
Region EASTERN SICHUAN, CHINA
Distances 90 km (55 miles) WNW of Chengdu, Sichuan, China
150 km (90 miles) WSW of Mianyang, Sichuan, China
360 km (225 miles) WNW of Chongqing, Chongqing, China
1545 km (960 miles) SW of BEIJING, Beijing, China
Location Uncertainty horizontal +/- 5.8 km (3.6 miles); depth fixed by location program
Parameters NST=228, Nph=228, Dmin=>999 km, Rmss=1.43 sec, Gp= 29,




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Tectonic Summary

The Sichuan earthquake of May 12, 2008, occurred as the result of motion on a northeast striking reverse fault or thrust fault on the northwestern margin of the Sichuan Basin. The earthquakes epicenter and focal-mechanism are consistent with it having occurred as the result of movement on the Longmenshan fault or a tectonically related fault. The earthquake reflects tectonic stresses resulting from the convergence of crustal material slowly moving from the high Tibetan Plateau, to the west, against strong crust underlying the Sichuan Basin and southeastern China.

On a continental scale, the seismicity of central and eastern Asia is a result of northward convergence of the India plate against the Eurasia plate with a velocity of about 50 mm/y. The convergence of the two plates is broadly accommodated by the uplift of the Asian highlands and by the motion of crustal material to the east away from the uplifted Tibetan Plateau.

The northwestern margin of the Sichuan Basin has previously experienced destructive earthquakes. The magnitude 7.5 earthquake of August 25, 1933, killed more than 9,300 people.