BEIJING, Sept. 30 (Xinhua) -- A strong earthquake measuring 7.7 on the Ritcher scale shook the south of Indonesia's Sumatra Island at 6:16 p.m. (Beijing time) Wednesday, according to the China Earthquake Networks Center.

    The epicenter was monitored at 0.8 degrees south latitude and 99.8 degrees east longitude, it said.

    A magnitude-7.6 quake, which was followed by a magnitude-6.2 aftershock, jolted West Sumatra province at Sumatra Island on Wednesday morning, causing the collapse of a number of buildings, local meteorology and geophysics agency said.