The San Andreas Fault in southern California gets more headlines, but the Cascadia Subduction Zone is a much larger threat by far. This fault zone is where the Juan de Fuca plate meets the North American plate, and it stretches approximately 700 miles from northern Vancouver Island all the way down to northern California.
When the 2011 earthquake and tsunami struck Tohoku, Japan, Chris Goldfinger was two hundred miles away, in the city of Kashiwa, at an international meeting on seismology. As the shaking started, everyone in the room began to laugh. Earthquakes are common in Japan — that one was the third of the week — and the participants were, after all, at a seismology conference. Then everyone in the room checked the time.
Seismologists know that how long an earthquake lasts is a decent proxy for its magnitude. The 1989 earthquake in Loma Prieta, California, which killed sixty-three people and caused six billion dollars' worth of damage, lasted about fifteen seconds and had a magnitude of 6.9. A thirty-second earthquake generally has a magnitude in the mid-sevens. A minute-long quake is in the high sevens, a two-minute quake has entered the eights, and a three-minute quake is in the high eights. By four minutes, an earthquake has hit magnitude 9.0.
When Goldfinger looked at his watch, it was quarter to three. The conference was wrapping up for the day. He was thinking about sushi. The speaker at the lectern was wondering if he should carry on with his talk. The earthquake was not particularly strong. Then it ticked past the sixty-second mark, making it longer than the others that week. The shaking intensified. The seats in the conference room were small plastic desks with wheels. Goldfinger, who is tall and solidly built, thought, No way am I crouching under one of those for cover. At a minute and a half, everyone in the room got up and went outside.
Comment: See also:
- Cascadia fault line in North America: A now still and silent subduction zone where disaster awaits
- On June 7, FEMA will hold a massive drill to prepare for a 9.0 Cascadia Subduction Zone earthquake and tsunami
- Magnitude 6.3 earthquake off coast of Oregon warns of Cascadia subduction zone slippage
as well as: