Earthquake off Northern California

merger writes "A 7.0 earthquake (7.4 according to NOAA) occured off of the northern California coast occured at 7:50 p.m. PST triggering a tsunami warning (which was then downgraded to a tsunami bulletin). While searching Google News for information I learned about an earthquake preparedness study for the area which was just published today."

Comments

East Bay Check In

[obsol33t]

Nothing felt here, most people will not even know about it until tomorrow in our area.

Tsunami info from a former park ranger

[bjackrian]

I worked as a Park Ranger at Redwood National Park a few years ago, and this is one of their nightmare scenarios. My housemate was a geology major, and the area right off of the coach is very susceptible to huge earthquakes (8.0+)--one happens every 200 or so years on average. The last one happened around 1700, so another one is fairly likely in the near future.

Towns like Crescent City are at huge risk, and the city and state are trying to compensate with warning systems (that have been improved since the tsunami in the Indian Ocean). While some buildings have been constructed to withstand tsunamis (the national park headquarters was designed as a "flow through" building so tsunami waves will just break out the first floor windows and flow through the building), the best advice is to climb. Get to high ground as soon as you feel the earth shake. Don't wait for a tsunami warning--just climb!

Also, don't go back to the ocean until you know for sure that it's safe to do so. Apparently, many of the deaths in the 1960s tsunami were a result of the mayor and several other people going down onto a pier to suvery the damage. Because tsunamis are really sets of high waves and sea levle changes, the next set of waves washed them away.

One more interesting tidbit--most tsunami deaths aren't caused by the water itself. Instead, what happens is that the water crashes into buildings destroying them. Additional waves then take all of that debris and use it like battering rams to destroy more buildings. It's the debris that most often causes human deaths and damage in the city. Perhaps a good case for building more tsnuami-safe buildings?

The Map didn't forcast it

[tod_miller]

http://pasadena.wr.usgs.gov/step/

If you look now though, there are two areas of fairly high risk.

Don't use this map for anything important, like planning picnics.

Still, I check this every day, and I am suprised that I was given a reference to test its accuracy so soon.

Still, it has updated today in light of the events.

False Alarm

[amcox]

According to a friend who is a geologist, the quake was on a slip fault, not a thrust falt, and therefore could not produce a tsunami. And, since it was something like 70 miles offshore, the shaking itself didn't do any real damage, either.