Earthquake in Tacoma 2.3

[C-Hawk]

Here's a great site for checking nation wide earthquakes

Magnitude 2.3
Date-Time Monday, November 7, 2005 at 12:50:29 (UTC)
= Coordinated Universal Time
Monday, November 7, 2005 at 4:50:29 AM
= local time at epicenter

Location 47.267°N, 122.460°W
Depth 11.5 km (7.1 miles) set by location program
Region SEATTLE-TACOMA URBAN AREA, WASHINGTON
Distances 3 km (2 miles) N (358°) from Tacoma, WA
5 km (3 miles) SE (131°) from Ruston, WA
6 km (4 miles) NE (46°) from Fircrest, WA
41 km (26 miles) SSW (194°) from Seattle, WA

[Robbi]

Fishtales,
I was sitting here at the computer yesterday and noticed an odd feeling, that kind of creepy feeling you get at the onset of an earthquake. The windows and other things made some odd noises. Then, nothing. Thought that is was just the wind. Thanks for the info. I now know that my earthquake sensors are still working. It was just a baby, but we need lots of those little guys! Thanks for the link to the USGS site, it's a good one.
Robbi

[Byrdman]

cool... anybody hurt?

[Luna C]

ya gotta get at least to a 4+ on the Richter scale before anyone gets too excited around here. 5+ in CA, I’m sure. 6’s will shake you up and get your attention. 7’s will start to do some real damage. It also depends on how deep the focus (actual movement) is.

here is a more official description:

M=1 to 3: Recorded on local seismographs, but generally not felt

M=3 to 4: Often felt, no damage

M=5: Felt widely, slight damage near epicentre

M=6: Damage to poorly constructed buildings and other structures within 10's km

M=7: "Major" earthquake, causes serious damage up to ~100 km (recent Taiwan, Turkey, Kobe, Japan, and California earthquakes).

M=8: "Great" earthquake, great destruction, loss of life over several 100 km (1906 San Francisco, 1949 Queen Charlotte Islands) .

M=9: Rare great earthquake, major damage over a large region over 1000 km (Chile 1960, Alaska 1964, and west coast of British Columbia, Washington, Oregon, 1700).

here is credit to those Canadians that put up the web site where I nabbed this info:
http://www.pgc.nrcan.gc.ca/seismo/eqinfo/richter.htm

[C-Hawk]

I received the web site from my ex-girl friend when she was with the USGS as a seismologist, she now works for the gov as nuclear treaty verification specialist.

[B~C]

That's quite the map Fishtales, I tuned in there to see what Mt St Hellens was doing and couldn't help but notice that you folks down south must be living on top of a giant slab of Jello.

side note- Mt St H displays a nice little steam plume whenever there is a clear day, still does a little quivering on a regular basis

[El and Bill]

Roger --

The USGS post also shows a link "For Kids Only" -- mailed it out to the Grandkids, and they love it!! We recommend it for anyone with young ones: http://earthquake.usgs.gov/4kids/

[El and Bill]

Roger's recent posting of a report of small earthquake in the Tacoma area is a reminder to all who live in the northwest that you live in a seismically very active area. And, not just the smaller quakes associated with Mt. St. Helens, but some mighty quakes with their own cause.

The largest earthquake ever reported for the lower 48 states took place in the Pacific NW (NOT California). About 9 pm on the night of January 26, 1700 all the northwest was shaken by an estimated 9.0 richter quake. To put this in perspective, the New Madrid Quake in Missouri in 1811 was an 8.1 (formerly thought to be the largest) and the San Francisco Earthquake was a 7.8 (the richer scale is exponential).

This Cascadia earthquake was about 100 years before Europeans lived in the NW, but tsunamis traveled to Japan and damaged cities on their east coast. Natives still tell the oral history of this event. Geological evidence from the sea floor, tree rings, and land level changes also record this huge event.

The earthquake resulted from the Juan de Fuca Plate (an offshore hunk of sea floor crust) sliding under the westerly moving North American Plate. These plates are still sliding today, and many small quakes are generated by their motion. Could such a large quake occur again? Geologically speaking, the answer is an unequivocal 'yes.' Megaquakes appear to have happened about once every 500 years, but they are not regular -- some have happened with only a two hundred year span.

A common question is whether small earthquakes, like the recent Tacoma event, will release energy on the fault zone and obviate a major earthquake. The answer is no, for the Cascadia region. A level 2 quake would have to be repeated one million times a day for 500 years to release the energy of one magnitude 9 event. This is not happening, so the rocks at the fault zone are slowly storing energy (like a coiled spring) that will, someday, have to be released in a large magnitude earthquake.

So, although much of the media focus for potential earthquake hazard in the US is on California (rightfully so), there is also high hazard in Cascadia (and Salt Lake City/Provo, Charleston, SC, St. Louis MO, and upstate NY and other areas). Perhaps the greatest threat in the NW is from a mega tsunami generate by a quake -- even more than the ground shaking.

Stay awake night worrying? Of course not, the event is unlikely in a lifetime -- but know what most So. Californians know -- what to do in the event of a quake to protect yourself and your family.