SINGAPORE -- A tsunami alert was issued after an earthquake of magnitude 7.4 struck 140 miles south of Banda Aceh in Sumatra, Indonesia, the country's quake agency and the US Geological Survey (USGS) reported on Sunday. "A destructive widespread tsunami threat does not exist based on historical earthquake and tsunami data," the USGS said. "However there is the possibility of a local tsunami that could affect coasts located usually no more than a hundred kilometers from the earthquake epicentre."