Wednesday, April 11, 2012

M8.6 and M8.2 earthquake, North Sumatra, Wednesday April 4th, 2012

A magnitude 8.6 earthquake occurred offshore of Banda Aceh on Wednesday, April 11, 2012 at 02:38:37 PM local time, not far from the location of the 2004 M9.1 event which triggered a tsunami killing almost a quarter of a million people across the Indian Ocean. Maps.

Two hours later at 04:43:09 PM local time, a M8.2 struck 180 km south of the first event. Maps.

The moment tensor solution unexpectedly show that its a strike-slip (i.e. a sideways movement on a transform fault, rather than the thrust fault we normally expect from a subduction zone earthquake). Moment tensor for the first event can be found here, click here for the second event.

There have been no immediate reports of damage or casualties. A tsunami watch notice was released for the entire region, but lifted two hours after the second event.