(Reuters) - The powerful undersea earthquake off the Indonesian island of Sumatra this week was a once in 2,000 years event, and although it resulted in only a few deaths, it increases the risks of a killer quake in the region, a leading seismologist said.
Wednesday's 8.6 magnitude quake and a powerful aftershock were "strike-slip" quakes and the largest of that type recorded, Kerry Sieh, director of the Earth Observatory of Singapore, told Reuters.
"It's a really an exceptionally large and rare event," he said.
"Besides it being the biggest strike-slip earthquake ever recorded, the aftershock is the second biggest as far as we can tell," said Sieh, who has studied the seismically active, and deadly, fault zones around Sumatra for years. Read More
Researchers from the U.S. Geological Survey said that for the three decades until 2000, seismic events averaged 21 a year in a central U.S. region. They jumped to 50 in 2009, 87 in 2010 and 134 in 2011...