Posted on 08/09/2007 1:01:19 AM PDT by Redcloak
Just had a nice little jolt here in the L.A. area!
I almost forgot the Landers quake...but that felt less severe in Burbank.
Actually, I was on the couch. : )
But seriously...
At our house, there's usually a very noticeable 1-1.5 second delay between the P and S waves from quakes that originate on the Northridge fault. Also, the P waves are very strongly felt here. (In fact, the P wave from the original Northridge quake almost launched me out of bed that morning.) And since we're so close to the fault, the frequency of the shaking is much higher than it is for more distant faults. Thus, Northridge fault quakes tend to be noisier and rattle things rather than shake them.
I was born in '63, so I've been through everything of any size since then; Sylmar, Whittier Narrows, Sierra Madre, the "Rose Bowl" quake, Landers/Bigbear, Northridge, and a few other big ones from way out in the southern desert. Though, I kinda missed the Whittier Narrows quake. I was driving to work that morning in a little pickup truck. At 80 MPH going down the I-210 toward the Tujunga wash, I was having my own, private earthquake! I didn't notice the extra shaking at all. It wasn't until I saw all of the dust getting kicked up back in the canyon that I realized that something big had actually hit.
I had just gotten off of work for that one and was standing at my front door wondering which way to go. But looking out at the parked cars rocking and rolling against their parking brakes, even outside didn’t seem safe. Later I talked to my brother and he was driving south on the “5” near Dodger Stadium when he thought he was having a blow out. He quickly realized that eveyone else was having the same blow out...The freeway slowed to a crawl.
An earthquake story from Alaksa:
My wife is from a part of Africa that rarely has quakes. When we were first married, one night, the cabin started shaking around and she woke up and shouted, “What is it?!” I rolled over, looked at her with sleepy eyes and said, “It’s about a four point five,” and I went back to sleep.
This was the first time she gave me the hairy eyeball and demanded that I explain what I meant.
Thanks for the note of explanation. And yes, seriously... If I’m up, I go out into the living room. Let the little lady sleep.
The quake awoke her. Can you believe that? I didn’t even feel it and it woke her up.
Dang!
I live just south of the epicenter - it was a Northridge-type jolt. Woke me up nice! Memories...
Not surprising.
California’s due for a big one sometime soon. And we’re due for a massive hurricane season soon, Yellowstone volcano should erupt in the next 100,000 years, the West is a tinderbox for wildfires which are raging right this instant during one of the dryest seasons ever, and tornadoes have reached the ground in Ohio right now.
This concludes the long-term doom forcast.
Doughty, why is that a 6.5 quake in LA isn’t enough to tip over a cocktail, but in the rest of the word causes quasi-apocalyptic death tolls, massive property destruction, and the wholesale canceling of dinner parties?
Is it just me or does it seem like we are on the verge of a pretty big one in Cali soon? There have been some real doozies on the pacific rim recently..especially in Asia.
Jeez Louise, please don't say that...I'm going from NY to San Francisco next week on business, I hate flying, and I'm terrified of earthquakes. I feel a panic attack coming on...
1971 Sylmar 6.6
1987 Whittier Narrows 5.9
and just missed the 1994 Northridge 6.7 when going back to L.A. to visit over the Christmas-New Years break by about a week.
Lived through the fires that surrounded the San Fernando Valley in the mid 70s. Got to eyeball a tornado in CO in 1978 while on Summer vacation.
Now I get to dodge hurricanes. ;)
Al Gore, stop your global whining, I’m tired of moving. /sarc
Lots of places in the world have simple rock and mortar homes. If we’re talking about the areas of Turkey, Pakistan and perhaps China, the buildings simply aren’t up to the codes ours are.
Even a 6.5 earthquake in St. Louis compared to one that might hit Los Angeles, would cause far more damage. LA builds to different codes based on it’s frequent quakes.
The New Madrid fault near the bootheel of Missouri and the upper north east section of Arkansas is over due for a large shake. If it were to go a lot of the Mississippi area of that region would be severely damaged. That quake could possibly cause damage up and down the eastern seaboard as well.
When this fault line broke in the early 1800s (I believe), it actually made church bells ring in Boston.
We texans have ... different disasters, so we can’t comment on EQs, but I’ve heard it’s better to have small quakes over time to relieve friction rather than no small quakes, just big ones?
Yes, the fault lines over time are going to travel. It is far better to have an average yearly move than to have that stalled for twenty years, and then have one three foot or more move in a few weeks, 75% of which happens on the initial quake.
Some faults like the San Andreas have changes in direction, not a straight light. The SA fault has a natural break built in. It doesn’t slip easily, and tension does build so that the proverbial ‘big one’ does take place from time to time.
Re the New Madrid EQ zone. The New Madrid EQs of 1811 and 1812 constituted 3 extremely severe quakes felt on the east coast and as far as Canada, as well as a number of other quakes of considerable size. In early 1812 there was also EQ activity in Venezuela that killed around 20,000. There was also a major eruption at St. Vincent in the Caribbean in 1812.
I have been studying this period for several years and just finished reading “The Big One: The Earthquake that Rocked Early America and Helped Create a Science” by Jake Page & Charles Officer, 2004. In other volcano and EQ studies I have noticed a 90 to 100 year pattern and a 180 to 200 year more severe pattern. By this observation it would seem that New Madrid might be ripe. However, in reading this book I found the following:
“In the 1990’s several workers from the Center for Earthquake Res. and Info. at the Univ. of Memphis...from 40 or so sites they determined that there had indeed been previous quakes of comparable size to the quakes of 1811-12. They were dated to about AD 500, AD 900, and AD 1450....The average interval, then, is some 430 years....Specifically, what we want to know is the probability of a monster quake [there] between now and the year, say, 2100. The answer is 20%.
Regarding previous EQ experience I was in a 7.5 in Mexico City in 1957 (the biggest since 45 years earlier). I was coming home from a party at 1:30 am. I started staggering and said to my date “I didn’t think that 2 drinks would affect me like this.” Being from California, he said, “It’s an earthquake”, grabbed my hand and we ran out into the middle of the street to get away from the 3 story houses, and the electric lines that were swaying the crackling together. We held onto each other to keep from falling down; it swayed around like a fast moving subway train. When I got home all the 3 foot tall flower pots in the apartment had fallen over, the guys upstairs had been thrown out of bed, one of the girls in our apartment said the chandelier (sp?) had been swaying so hard that it was hitting one side of the ceiling and then the other. A friend said that downtown the “little Empire State building (over 30 stories) was swaying back and forth, and all the prostitutes ran out into the street and were screaming and praying hysterically. Almost 200 people altogether were killed. Mostly in an apartment building that crumbled. Graft in inspections was charged.
I am interested in the problam of low cost earthquake resistant structures. I thank that strawbale structures might be particularly good. I look for one in hurricane country last year on a business trip. Found one outside Pensacola, Florida. It had suffered no damage in Hurricane Hugo, whereas neighboring buildings had considerable damage, and one foot diameter trees had fallen 200 feet away.
Wow, if prostitutes were praying, it must have been some quake. :’)
It was some quake. As I said my date and I were holding on the each other to keep from falling down, like on a fast moving New York subway train.
My apartment overhung the parking area during the Sylmar quake, had a pretty wild ride.....nothing like Northridge, though. I'll never forget the picture of a section of the 14 to 5 overpass where it collapsed just before a motorcycle cop went sailing over it to his death.
2 years earlier, I was driving that route every morning.
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