7.2 Earthquake SoCal Area

[CaLiMoMof2]

DH spoke to his mom about an hour ago, she lives in Hemet, Ca and she said they felt it there also.

 

[JBean]

http://sciencedude.freedomblogging.com/2010/04/04/6-9-earthquake-near-san-diego-shakes-o-c/95905/


The most severe earthquake to affect Southern California in almost 20 years erupted at 3:40 p.m. today on a poorly understood fault below the U.S.-Mexico border, 19 miles southeast of Mexicali, producing prolonged shaking that was felt by at least 10 million people across at least three states, including residents 270 miles to the northwest in Orange County, where brief, isolated power outages were reported. (Live quake map.) The quake has triggered many smaller quakes in Southern California, including one at the south end of the potentially dangerous Elsinore fault, a zone that extends into Orange County.

 

[JBean]

A power outage linked to the San Diego earthquake is still going on in Dana Point and Laguna Niguel, according to Jennifer Ramp, spokeswoman for San Diego Gas and Electric that provides electrical service for the area.
After the earthquake 3,854 customers were without power and now about 2,300 customers are still without power. Electrical service was expected to be restored by 10 p.m., but at about that time the new service restoration time was updated to 1 a.m.

http://www.ocregister.com/articles/power-242562-service-diego.html

 

[hollyblue]

I have no idea what that is like? I don't think I could take it. Dealing with hurricanes and tornadoes is plenty for me.

I agree. Atleast you have some idea what may be coming. In an earthquake....it's SURPRISE!!!!!
Was only in a small one in Idaho, but I was scared...had only been there 3 mos.

 

[STEADFAST]

An aftershock around 4:20 this morning woke my husband and son up -- not me, though.
News is showing the damage in Calexico from the shake yesterday. They say the town center area has been closed because of structural damage and the need to check buildings out.

 

[Herding Cats]

It looks like the original quake was on the Elsinore fault, Laguna Selada section. The actual fracture zone is in Mexico, and I can't find good information on faults there (and they're likely named something else). (more information here: http://www.data.scec.org/fault_index/elsfault.html).

It is a right lateral side slip, meaning displacement usually is not up/down, but side to side (of course, some up down happens just because of the earth's movement). The last major slip was in 1910, and it was a 6.0. Yesterday's quake is a big quake for that fault. The slip aspect will explain why a lot of lateral motion was felt - e.g. Yuma, San Fernando, and mountains but not felt in places which had a large basin to cover (e.g. Bishop, Nevada); the energy from this (relatively shallow) quake spread out in a ripple effect, and lost energy at the far ends of the concentric circles. If you picture a pond with a rock dropped into it, the ripples will be seen closer to the original entrance point, and if there is nothing to rebound from (like the shore, the boat, a big rock), eventually the ripple will disappear over a long, open stretch. This would also account for why mountainous regions felt this when flatlanders didn't.

What I find interesting (and scary) is the pattern of quakes reverberating upwards into California - on the San Andreas as well as other faults in the area. Most of these cannot be considered "aftershocks", as they are not on the same fault; instead, they are their own quakes caused by displacement pressure from the first quake in Mexico.

My concern, as it is with all large quakes, is what pressure will this add to local fault lines (and not so local, as in San Andreas), and what will that pressure do?

When I can be scientific about it, it's very interesting. When I am just being me, it scares the hoooey right out of me. I've been through a whole lotta quakes, and I never had fun in any of them...(except the little ones...).

Best-
Herding Cats

 

[legalmania]

Does anybody think that maybe some of these fault lines were created back in the days when the defense department use to test nuclear weapons in the dessert?

 

[fran]

Does anybody think that maybe some of these fault lines were created back in the days when the defense department use to test nuclear weapons in the dessert?

NO.

JMHO
fran

 

[legalmania]

NO.

JMHO
fran

Well that was a cut and dry answer. Read this and it may change your mind.

http://www.groundreport.com/Business/Past-Nuclear-Testing-Contributing-To-Natural-Disas_12/2918054

 

[STEADFAST]

Does anybody think that maybe some of these fault lines were created back in the days when the defense department use to test nuclear weapons in the dessert?

The earth's fault lines predate mankind, let alone nuclear testing, by millions of years. For instance:

The San Andreas fault is the foremost of a large set of faults along the plate boundary between the Pacific plate on the west and the North American plate on the east. The west side moves north, causing earthquakes as it moves. Over millions of years, it has brought very different sets of rocks to face each other across the fault trace. The forces associated with the fault have pushed up mountains in some places and stretched apart large basins in others. The mountains include the Coast Ranges and the Transverse Ranges, both of which consist of many smaller ranges. The basins include the Coachella Valley, the Carrizo Plain, the San Francisco Bay, the Napa Valley and many others. http://geology.about.com/od/geology_ca/tp/aboutsaf.htm

The San Andreas Fault and its geologic significance was discovered in 1895 by Andrew Lawson. http://www.worldandi.com/subscribers/feature_detail.asp?num=25035

Also, the largest thermonuclear bomb ever tested released less energy (7.1) than the earthquake that hit Mexico yesterday (7.2), and far, far less than many previous earthquakes. The San Fransisco Earthquake in 1906 was ten times more powerful. The 1964 Anchorage Earthquake was a hundred times more powerful. http://simple.wikipedia.org/wiki/Richter_scale

 

[sealevel]

Went to my office in downtown San Diego today. No damage, just things knocked over and moved around a little. One of my co-workers was camping in Ensenada over the weekend and they were delayed trying to come back across the border. No injuries or damage reported by my co-workers, but our El Centro office is closed for damage assessment. There have been quite a few aftershocks, I was woken by the one at 4:30 am, and there was another at 6:30 am that was pretty strong. All-in-all, it looks like we dodged major damage and injuries, so we are very lucky. Still not sure of the damage in Mexico, closer to the epicenter.

 

[legalmania]

The earth's fault lines predate mankind, let alone nuclear testing, by millions of years. For instance:
The San Andreas Fault and its geologic significance was discovered in 1895 by Andrew Lawson. http://www.worldandi.com/subscribers/feature_detail.asp?num=25035

Thanks you STEADFAST for that very detailed answer. I saw a documentary the other night, the government was testing after World War II to see how much nuclear power they would need to sink 100 ships. They tried it several times, one explosion was so strong that it caused a 100 foot tsunami and coral rock flew up to about 5,000 ft. and when it fell back to the earth it was frozen. All the ships did not sink but the Sara toga did and that's how she ended up on the bottom of the ocean. I know the faults have always been here, but scientist are now considering the possibility that nuclear testing expanded the fault lines.

 

[legalmania]

Went to my office in downtown San Diego today. No damage, just things knocked over and moved around a little. One of my co-workers was camping in Ensenada over the weekend and they were delayed trying to come back across the border. No injuries or damage reported by my co-workers, but our El Centro office is closed for damage assessment. There have been quite a few aftershocks, I was woken by the one at 4:30 am, and there was another at 6:30 am that was pretty strong. All-in-all, it looks like we dodged major damage and injuries, so we are very lucky. Still not sure of the damage in Mexico, closer to the epicenter.

Glad everyone is safe, good thing they have such strong building codes in California, compared to Mexico where I don't think they have any at all. I remember in Haiti they had an aftershock about the third day, that was almost as strong as the first one.

 

[fran]

I have been trying to maintain my cool over this quake. But as time goes by, it becomes more difficult with each after{shoooock!}

My nerves are frazzled and even my cats have stopped purring.

{stop! already!}


fran

 

[sealevel]

That one a few minutes ago was the strongest I've felt since the original.

 

[STEADFAST]

Yeah, I keep feeling the aftershocks, too. (There was one like two jerks about ten minutes ago.) There have been quite a few of them. I think I'm sort of hyper on-guard at this point.

 

[STEADFAST]

That one a few minutes ago was the strongest I've felt since the original.

It was a 4.6, pretty close to where the original quake was.
http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/ci14617100.php

 

[Rob1977]

That was the biggest earthquake I remember since 1994. Our pool tsunami'd. No damage though. Thank God.

 

[fran]

I was born and raised in So. California. I've been through all of the big ones. But this, this WAS THE BIG ONE to DATE!

I've never felt this many after-shocks before. The after-shocks are scarier than the original quake, a bit, because you fear any second there will be more.

Thank goodness I didn't have any damage. But I have loved ones in Calexico and I can't say the same for them. They lost just about every glass dish in their kitchen. Plus, Calexico was closer to the epicenter and suffered quite a bit of damage.

My son came to me about two weeks ago, just after the Chile quake. He brought up the series of recent quakes and said, 'We're next.'

Saturday, my cats acted weird. They would suddenly stop, looked frightened, looking around for a few minutes. I thought to myself, 'Are we going to have an earthquake?' But nothing..................until Sunday...........

A while ago when we had that good after-shock, my cats just sat there staring around, looking for something?

I've been through the Simi Valley quake, Landers, all.................but this one was the worst yet. Then the after-shocks are sooooo unnerving!

JMHO
fran

PS......LOL, imagine the original 7.2.......three of my daughters and one of their girlfriends were here. I was fixing dinner and all of a sudden they all stopped,........................they heard it coming....(I had the microwave on so didn't know what was up until................) we were like a comedy if it wasn't so serious. One daughter wanted to run outside! (uhhhh...NO!)......another hid behind the couch,..............and I went under a doorway................Then we all told each other "No! that's not what you're supposed to do!" I felt like the three stooges, only it was FIVE STOOGES! {{{{{{scary}}}}}}

 

[PaperDoll]

I haven't felt any after shocks. hum :waitasec: However, the quake did stop our clocks, we have a few pendulum clocks.

Fran, :blowkiss: I understand your feelings. These earthquakes can leave me a bit shaken, seems like we are always hearing about the BIG ONE and when will it strike. That is enough to scare anyone.

Too funny, I decided to NOT renew my earthquake insurance this year, and low and behold my insurance company calls me today to remind me that I need to renew my insurance. :crazy: We have been through many earthquakes and nothing has ever fallen or been broken.