Enormous Earthquake

I woke up this morning to a boatload of emails from the USGS automated earthquake notification email service I subscribe to. They are all associated with an enormous earthquake that occurred east of the Kuril Islands at the boundary between the Pacific plate and the Okhotsk plate. The original magnitude was estimated at 7.7 but was later revised to 8.2. This is similar in size and not to far away from a magnitude 8.3 earthquake that struck the region back on November 15, 2006. This is of course much larger than the magnitude 6.9 Loma Prieta earthquake that rocked the San Francisco Bay area in 1989, and much smaller than the magnitude 9.1 Sumatran earthquake that spawned tsunamis that killed more the 250,000 people. Earthquake magnitudes are logarithmic and describe the size of the amplitude of waves on a seismogram. So, this recent quake in the Kuril Islands is roughly 20 times larger than the Loma Prieta earthquake. The amount of energy released during the earthquake is different, using a calculator supplied by the USGS I calculated that this recent quake released roughly 126 times more energy that Loma Prieta. According to the moment tensor solution it was a normal fault earthquake (see below).
It looks like the area is remote enough that there is no direct damage from the quake. Especially after the Sumatran quake the first concern of many is a tsunami. At least according to the Anchorage Daily News it looks like the tsunami warning has been lifted, which is of course good news.

Advertisements