Sunday, April 26, 2015
Nepal Earthquake - Aftershocks Shocking
This zone is 200 km long. A true M8 would be 300 km long. The footwall is probably to the north, and all the populated areas are on the hanging wall, where all the aftershocks are. We are lucky the city wasn't in the true 'hammer zone' of the thrust fault. This happened with the Armenian earthquake, which was only an M7 but the city was on the zone.
Same with Kobe -- an M7 with attitude. Aftershocks can bring down damaged buildings, and sometimes cause more disasters (remember Christchurch?). Some of these aftershocks are closer to the populated areas, so the PGV can be higher.
In Toronto, we have a lot of people right on the potential zone. The chance for a big earthquake here is exactly the same as all these other places, every few hundred years in the same spot. Oklahoma City may have a slightly greater chance. :)