The powerful undersea earthquake off the Indonesian island of Sumatra this week, was a once in 2,000 years event and increases the risks of a killer quake in the region, Kerry Sieh, director of the Earth Observatory of Singapore, told Reuters.
※"Besides it being the biggest strike-slip earthquake ever recorded, the aftershock is the second biggest as far as we can tell," said Sieh. Strike-slip quakes involve the horizontal movement of colliding earth plates and are typically less powerful than those where there is vertical movement. They are also less likely to trigger big tsunamis.