Friday, June 17, 2005

more aftershocks

Another earthquake and aftershock offshore, closer to Eureka than last time, apparently occured last night. We felt nothing here, however. I've occasionally felt tremors that could be earthquake activity but they were so slight and brief that there was no way to tell.

According to reports I was able to find, the big quake (now upgraded to 7.2 in some reports) as well as the one last night, a 6.6, were side-to-side quakes, the result of plates brushing past each other as they move, rather than one sliding under the other. The side-to-side quakes generally don't cause tsunamis. So this was not the kind of quake that geologists know is coming, which will involve plates colliding and pushing each other up and down. That kind is likely to be more destructive.

It's pretty interesting to watch the coverage, though. Very little hard information about the actual quakes, and lots of human interest about how people were scared or were not scared. Most stories emphasize an alarmist tone, and try to make drama even where there isn't any.
That's pretty troubling when something is potentially important. When a bad quake does hit, we are going to need timely information, and I see nothing to give me confidence we will get it.

Even the earthquake maps from official sources aren't keeping up, and are maddeningly short of the kind of information that would help a somewhat informed citizen to understand what's going on.

On the whole, if this is a kind of shakedown cruise for a real crisis, it is not providing a lot of confidence.

Earthquakes all up and down the west coast, from South America to Alaska, have been more numerous and larger this past week. Southern CA got a 5.3 yesterday. But again, whatever the geologists are saying to each other isn't getting reported very well. Very disappointing, and potentially dangerous.

Wednesday, June 15, 2005

after shocks

There have been several small earthquakes offshore since the 7.0 about 24 hours ago. Several seem to have been aftershocks, but others are farther south. There was a 3.6 or so off Petrolia, south of here and pretty much at the triple junction, at about 7:30 pm. Didn't feel it here, and haven't felt any of the others since the 7.0.

So far nothing I've seen online or in print is very informative about the nature of these quakes. The Gorda plate was involved in the 7.0, is as technical as the info I've seen has gotten.

News reports, such as they are, emphasize the human response. According to the brief story in the Times-Standard, Trinidad north of here evacuated a few people in low-lying areas near shore, when the tsuanmi warning was issued. Trinidad just held a practice drill.

Tuesday, June 14, 2005

Earthquake Off North Coast continued

It's about three hours after the quake now. Reports to the CA earthquake center indicate that it was felt up and down the entire state, as far south as San Diego. At least 30 reports from the Bay Area, and now there are hundreds logged from Eureka, Arcata, McKinleyville.

According to the SF Chronicle, downtown Crescent City was evacuated immediately, several thousand people moved according to plan, but they started going back when the tsunami wave didn't hit. That's an iffy thing actually, because the first wave is seldom the biggest.

No reports of damage yet. Tomorrow we'll probably find out more details about location and what plates were involved. I have to say that when I first felt the ripple I thought I heard it say, this isn't over.

It's Happened---Earthquake on the North Coast

Here in Arcata at a little before 8 local time, I felt the rippling beneath my chair. The room rocked a bit, not enough to be alarming, but longer than I've experienced here before.

So I was bit surprised to see on the earthquake map what had happened: a pretty big one, a 7.0 offshore, looks to be in the subduction zone, about 80 to 90 miles off the coast, between here and Crescent City to the north.

The AP is reporting that a tsunami warning has been issued, and some evacuation is proceeding in Crescent City. A few of our friends in McKinleyville are heading for higher ground with other friends in the mountains. We're on the ridge near Humboldt State, and on the maps Lori Dengler and others prepared of tsunami hazards locally, we're in the white (no danger) zone, and that's for an even stronger quake.

Tsunami waves radiate out from the quake itself, and can travel at hundreds of miles an hour, so I suspect that our coast should be feeling something soon.

Otherwise it's quiet in the neighborhood. I don't think many people here even felt it, although there are at least 60 reports to the CA earthquake center from Eureka, and a couple from San Francisco---even one from L.A. This zone travels way up the coast to Vancouver as well. It's interesting that online there doesn't seem to be a source of really timely information. It's been more than an hour and all I've seen is the one brief AP story on the SF Chronicle site. And the real-time reports on the CA earthquake site.

UPDATE: As of 920, a new AP story says the tsunami warning has been called off.