Cascadia Subduction Zone

Monday, April 30, 2012
10:49 A.M.

I know it’s been a while since I’ve posted. Sorry.

I actually haven’t been doing a whole lot of weather related things lately. The weather has been pretty boring around here (and it probably will be until October), so I’ve been focusing on other earth sciences that interest me.

In particular, I’ve been reading a lot about the Cascadia Subduction Zone. Remember that huge earthquake that occurred last year in Japan? We’ve got a fault off our coast that bears a lot of similarity to the fault that caused that earthquake and tsunami in Japan last year. I’m sure many of you knew that we live in an earthquake-prone region, especially if you lived through the 2001 Nisqually Earthquake, but I don’t know how many of you have really thought about what would happen if we saw an earthquake like the one Japan saw last year.

Huge subduction zone earthquakes like the one in Japan last year and the one in the Indian Ocean in 2004 are called “megathrust earthquakes.” Megathrust earthquakes are the most powerful type of earthquakes and completely overshadow all other earthquakes in the amount of energy released. To get an idea of the amount of energy these earthquakes release, take a look at the pie chart below. The three largest earthquakes ever recorded (Sumatra, Alaska, and Chile) make up about half of all the seismic energy released in the past 100 years. The 7.9 earthquake that devastated San Francisco in 1906 is practically invisible on this pie chart.

If a megathrust earthquake were to occur off our coast, many coastal communities would be wiped out from the tsunami and major cities like Seattle and Portland would suffer heavy damage from the earthquake itself. We are not prepared for such a disaster.

I’ve got to go to class now… I know this isn’t the most elegantly written post I’ve ever created. But it is food for thought.

Charlie