Seismologists say the two minutes of horrific shaking that razed entire towns was caused by two distinct shifts of the Longmenshan Fault, which stretches southwest to northeast across Sichuan. (Epicenter area map)
Yuji Yagi, an associate professor at Japan’s Tsukuba University, said that a 60-mile-long and 18-mile-wide section of the fault initially ruptured about 23 feet.
Then another section, about 90 miles long and 18 miles wide, to the northeast of the first section sheared about 13 feet a few seconds later.
The resulting seismic tremors were felt as far away as Tokyo, Bangkok and south-central Russia’s Tuva Republic.
Monday’s quake occurred at 2:28 p.m. local time and was China's deadliest since approximately 255,000 people were killed by a 7.8 magnitude temblor that devastated the city of Tangshan, near Beijing, in 1976.
