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Posted on 02/22/2011 6:24:08 PM PST by decimon
CORVALLIS, Ore. – The terribly destructive earthquake that just hit Christchurch, New Zealand, was only a moderate 6.3 magnitude, but had certain characteristics that offer an important lesson to cities up and down the West Coast of North America that face similar risks, experts say.
The New Zealand earthquake killed dozens – and some fear the death toll may rise to the hundreds – and was an aftershock of the much more powerful 7.1 magnitude earthquake that struck that nation last September near the same area, but caused no deaths.
Even though this earthquake was weaker than last year’s event, it was much shallower; was situated directly under Christchurch; hit during the lunch hour when more people were exposed to damage; and shook sediments that were prone to “liquefaction,” which can magnify the damage done by the ground shaking.
Robert Yeats, a professor emeritus of geology at Oregon State University, who is an international earthquake expert and researcher on both New Zealand and U.S. seismic risks, says that same description nicely fits many major cities and towns in Washington, Oregon, California and British Columbia.
“The latest New Zealand earthquake hit an area that wasn’t even known to have a fault prior to last September, it’s one that had not moved in thousands of years,” Yeats said. “But when you combine the shallow depth, proximity to a major city and soil characteristics, it was capable of immense damage.
“The same characteristics that caused such destruction and so many deaths in Christchurch are similar to those facing Portland, Seattle, parts of the Bay Area and many other West Coast cities and towns,” Yeats said. “And it’s worth keeping in mind that New Zealand has some of the most progressive building codes in the world.
(Excerpt) Read more at oregonstate.edu ...
Ping
We in L.A. have understood this for quite some time.
I was 3 miles from the epicenter of the Northridge Quake.
No fun.
Looks like the Christchurch quake took them by surprise. Not an area of active fault, till last September, and quite damaging for a 6.3 quake.
I pray for my dear friends in Christchurch...So much damage, so many dead and I fear I may know some of them.
>>Looks like the Christchurch quake took them by surprise. Not an area of active fault, till last September, and quite damaging for a 6.3 quake.<<
That is what worried me. All current data say that there is no place in the world better prepared than L.A. for an earthquake (one of the few things we have done well). For it to come out of the blue, without the constant building code revisions we have here: from the SF quake of 1906 through L.B. quake of 1933, the San Fernando quake of 1971, Prieta Loma, Whittier Narrows, Northridge, etc., we have constantly upgraded the building requirements, and the last go-round was really the best we have ever done: getting dang near every overpass and building reworked.
Most places just have old standards that can’t really withstand quakes. I was saddened that there were so many killed in NZ, but I also had to note that it could have been much, much worse.
It's different when it's personal. I trust you'll find your friends are well.
The Northridge quake occurred on a fault that was previously unknown and had never been active in historic time. It was the costliest quake in American history. My house was further from it than freedumb's but the temblor packed a terrifying wallop. I'm still fearfully waiting for the next "aftershock." Sometimes they don't occur for decades.
Published accounts by Caltech seismologists at the time mentioned the entire L.A. Basin is riddled with similar undetected faults that will eventually flatten all the expensive development on the surface.
Those of us who live in pleasant coastal subduction zones should accept as a fact of life that the Devil can have a nightmare any time. When he shifts position and squirms, all Hell breaks loose on the surface.
Pretty creepy when you consider it inevitable, not theoretical.
It's the human perception of time vs. geologic time. Viewed from the perspective of what's happened in the past our species is probably doomed.
After the big quake offshore from San Simeon a few years ago my daughter moved from Morro Bay, CA (where the quake was strongly felt) to the coastal region of Oregon. She wrote me that she was finally far from earthquake danger. I wrote back telling her to Google "Cascadia Subduction Zone."
She's laying in plenty of water and supplies. When that baby lets loose the San Andreas will seem like Amateur Hour.
Theres 75 dead and about 300 missing now
I cant make a post because this is the Christchurch newspaper The Press
http://www.stuff.co.nz/the-press/4692170/Christchurch-quake-toll-75-dozens-missing
Christchurch Quake Map
5040 quakes; Shows every quake since Sept 4, one by one by one.
http://www.christchurchquakemap.co.nz/
Is Christchurch headed for a volcanic eruption?
http://www.iceagenow.com/Is_Christchurch_headed_for_a_volcanic_eruption.htm
Engineer concurs - Christchurch could be
headed for volcanic eruption
Subduction-zone volcanoes never go extinct, only dormant
Includes cities of Timaru, Oamaru and Dunedin
http://www.iceagenow.com/Engineer_concurs-Christchurch_could_be_headed_for_volcanic_eruption.htm
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