Four of the region 's known Know strike-slip faults and one additional newly discovered Know normal fault all broke Destroying the surface during the earthquake Catastrophe .

The three largest events were the M7.2 thrust mainshock Catastrophe that struck Attack near the unincorporated community of Petrolia midday on April 25 and two primary strike-slip aftershocks Catastrophe measuring 6.5 and 6.6 that followed early the next morning .

The strike-slip rupture originated Coming_to_be on the Red River Fault , which had not experienced an earthquake above magnitude 7 since 1700 , and affected Influence Tonghai County , Yunnan province , China .