M4.1 Earthquake in Los Angeles area

From USGS:

Earthquake Details

  • This event has been reviewed by a seismologist.
Magnitude 4.1
  • Wednesday, August 08, 2012 at 16:33:22 UTC
  • Wednesday, August 08, 2012 at 09:33:22 AM at epicenter
Location 33.908°N, 117.778°W
Depth 9 km (5.6 miles)
  • 3 km (2 miles) NNE (22°) from Yorba Linda, CA
  • 8 km (5 miles) ENE (68°) from Placentia, CA
  • 9 km (6 miles) SW (214°) from Chino Hills, CA
  • 13 km (8 miles) NE (52°) from Anaheim, CA
  • 46 km (29 miles) ESE (111°) from Los Angeles Civic Center, CA
Location Uncertainty horizontal +/- 0.3 km (0.2 miles); depth +/- 0.7 km (0.4 miles)
Parameters Nph=190, Dmin=9 km, Rmss=0.39 sec, Gp= 18°,

M-type=regional moment magnitude (Mw), Version=2

Event ID ci15189281
  • Did you feel it? Report shaking and damage at your location. You can also view a map displaying accumulated data from your report and others.

h/t to WUWT reader “Rusty”

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Douglas von Roeder
August 8, 2012 9:48 am

The quake occurred this morning.
I live in Irvine, CA and I woke up at that time.
There was an aftershock here a few minutes ago. I felt what seemed to be a “push” on one side of my chair. Nothing more.

Skeptic Tank
August 8, 2012 9:54 am

Must be the heat.

August 8, 2012 9:58 am

I live in Yorba Linda. 4.5 last night before bed, then a 4.5 this morning, followed by a 3.4 20 minutes later. It’s feeling like a flurry. I hope that’s the last of them.

Darren Potter
August 8, 2012 9:58 am

Where is the obligatory press release out of N.A.S.A. proclaiming Hansen’s latest paper demonstrates a clear and unprecedented perceived connection between man induced warming of the Northwestern Hemisphere and the increased frequency and severity of Earthquakes therein?

August 8, 2012 9:59 am

Last one is stronger at M4.5
MAP 4.5 2012/08/08 16:33:22 33.898 -117.792 8.0 GREATER LOS ANGELES AREA, CALIFORNIA

Climate Refugee
August 8, 2012 10:01 am

It´s the CO2 again, just wait and see

Steve Wyn
August 8, 2012 10:02 am

Upgraded to a 4.5: http://earthquake.usgs.gov/earthquakes/recenteqscanv/FaultMaps/118-34_eqs.html
They had another 4.5 at 11:30 last night in same spot.
I’m 20 miles west in Long Beach, CA. Felt a gentle roll here.

August 8, 2012 10:03 am

I lived around there the first 40 years of my life. Not sure I’d even notice a 4.1…

August 8, 2012 10:05 am

The support tech I’m on the phone with reported the first one at 9:33 and noted that on the 4th floor where he is that it shook his computer. He later reported a very short after shock. Hmm, 10 – 15 minutes after the first one.

August 8, 2012 10:05 am

That’s two M4+ quakes in 24 hours on the Whittier fault zone. No joy in that. Many large quakes have been preceded by a pair of M4-M5 quakes.

August 8, 2012 10:15 am

No doubt AGW will be blamed…

kadaka (KD Knoebel)
August 8, 2012 10:41 am

So what happened, did Al Gore, while visiting his California mansion, fall out of bed? Or fall off a masseuse?
Isn’t “Chakra Release!” used to cause earthquakes in some of that Japanese videogame-type anime? Al should be more careful.

August 8, 2012 11:01 am

Have been through several of ~7 within a couple miles of epicenter. Just my luck. They are amazingly violent. The noise is deafening. Now all my large case furniture is bolted to the walls, cabinet doors are rigged not to open, dogs are on there own. No more resorting hundreds of CDs,books, etc.
Good luck to all in LA!

August 8, 2012 11:01 am

I found the “Live Earthquake Mashup” from ‘The Ö-Files’ at http://www.oe-files.de/oefiles/gmaps/eqmashup-info_html to be very helpful in following swarms of ‘quakes in close-to-real-time. Good luck to you folks in CA.

August 8, 2012 11:08 am

I would like to apologize for the earthquake. We were jumping on the trampoline, and apparently I put on a few more pounds than I’d realized…

August 8, 2012 11:37 am

Here’s a question.
Are “head crashes” a problem for computers during earthquakes ?

August 8, 2012 12:36 pm

Where’s Hansen on this – shouldn’t he be issuing a press release claiming that this is more extreme “weather” caused by man? Can we expect increased earthquakes if we don’t lower our CO2, Jimbo?

Steve C
August 8, 2012 1:01 pm

George, it’s comments like that which make me v-e-r-y glad not to be anywhere near LA. O_O

kadaka (KD Knoebel)
August 8, 2012 1:11 pm

u.k.(us) said on August 8, 2012 at 11:37 am:

Here’s a question.
Are “head crashes” a problem for computers during earthquakes ?

If the computer falls off the desk and hits hard while the hard disk drive is in use, sure, it could be.
If the drive is not in use, these days it’ll probably be fine. Wikipedia has a good write-up here describing how modern HDD’s are given “shock resistance” (impact, not electrical).
I am old enough though to remember the warnings about how a system can get screwed up if the drive is writing critical data, like a system file, when there’s a power loss, as can happen with earthquakes. The technology is there to sense a power loss (or sudden movement) and safely park the heads. But they can’t hurry up and get a file written, and if something like the Master Boot Record gets screwed up from a discontinued write, the hard drive could be bricked or the system otherwise unbootable.
Of course if you upgrade to a Solid State Drive, at least for important files like the OS and programs, you’re much less worried about physical impacts. And hey, they’re getting cheap. I’m pricing them now, looks like I can get twice the capacity for half the money compared to last year.

Ben D Hillicoss
August 8, 2012 1:12 pm

Lived in Los Gatos California in 1987, we had a dozen or so 4.0 to 5.0 magnitude quakes leading up to the Loma Preada (SP) earthquake of October 17th 1987, I hope and pray these are not that…killed people from Okland and San Francisco to Santa Cruz.

Pieter Folkens
August 8, 2012 1:26 pm

I just heard on ABC top-of-the-hour news on the radio that some dolt is proclaiming that AGW causes increased earthquakes. He went on to say that July was the warmest on record.

August 8, 2012 1:26 pm

I wonder if it was caused by global warming… err, climate change disruption.

August 8, 2012 1:29 pm

It’s very easy to be facetious about these things. After all, the CAGW hoaxsters claim every bad thing that happens is caused by global warming/climate change. Let’s hope we can continue to make light of these quakes. After all, as much as I dislike the majority of Californians, I still don’t wish a major natural catastrophe on them. The man made catastrophes they are creating are doing enough harm to them and the rest of the country.
Jay Davis

August 8, 2012 3:36 pm

I’m sure that we will find out that it’s actually caused by Global Warming, Climate Change, Climate Disruption, Climate Instability, ……….I forget..

August 8, 2012 5:50 pm

Dammit, my wife stomped out of the bedroom this morning demanding to know who broke her favorite trophy. I checked, and sure enough, the quake had knocked her big triple-decker trophy off the side table and broken it, along with a picture frame. Which really was a nuisance because it was 100 degrees outside today and I had to go into the even hotter garage to fix the thing. I got a hug for it, so the earthquake did me a favor. Wish I could do something about that global warming in my garage. It’s an oven in there in the summer.

Bob Diaz
August 8, 2012 6:27 pm

Here’s Southern California’s new Theme Song:


August 8, 2012 7:07 pm

Ok, I’m not a geologist. And yet, I have followed arguments about earthquake patterns such as in Asia Minor. The concept is the stress of one earthquake can be transferred to the next segment after the first ruptures.
Does anyone recall the two rather large earthquakes a few years ago in the Gulf of California? One was south of San Felipe, and the next one was very close to San Felipe about 6 months or so later. I thought, well, perhaps we are seeing the same transfer of stress to the next segment happening on the San Andreas.
My hypothesis could be tested by looking for additional activity on northern fracture zones. Since we haven’t had “the big one” down south, the zone is perhaps more locked than other segments. That makes sense because there is a very big bend there. Clearly, the crust has to slip in more than one direction to allow the pieces to move along the curve. The faulting is very complex in Southern California.
Since the two Baja quakes, I’ve been paying attention to the activity in the area from the gulf to Parkfield and past Tehachepi. Over the last two or more years there has been more and more movement farther north. Now the entire region from the Salton Sea to the Southern Sierra is lighting up with many small earthquakes. They appear to be ocurring at 10 to 100 times the frequency they did prior to the Baja quakes. They are typically low magnitude, but they were not happening at the same rate before.
Neither of the two (yes there were two of them) magnitude 4 earthquakes (one reported here) were very big, and certainly didn’t release much energy, or relieve much stress. The last somewhat big one I was in was the Loma Prieta, where I was on the 15th floor of UC San Francisco. That was a wild ride. My experience is you don’t get mag 6 earthquakes before the 7. As I recall, we would get an occasional 5, and they were ‘fun’. Loma Prieta was not fun.
I would say get ready. But you should be ready anyway. I’m heading down to Burbank this weekend to hang out with the somewhat spineless pachyderms (still better than the other choice). I’ll be driving past Ft. Tejon where the last rather big earthquake happened down south in 1857 [http://earthquake.usgs.gov/research/parkfield/1857.php]. When you drive over the Grapevine the tangle of faults is amazing, if you know what you are looking at [http://earthquake.usgs.gov/earthquakes/recenteqsus/Maps/special/California_Nevada.php].
I have no idea when the “big one” will happen, so I’m going down there. Maybe I’ll have a nasty story to tell, but I hope it’s a very boring trip. I do think the next SoCal big one will happen soon. But what do I know?

August 8, 2012 8:14 pm

Let’s stop all the speculation as to the cause of this quake. Harry Reid will tell us the truth about it tomorrow. /sarc

August 8, 2012 9:02 pm

Don’t blame me. It isn’t my fault.

August 8, 2012 9:35 pm

This is news? Where I lived 4.5’s happened pretty regularly (Rogers Creek). Had a 4.6 with epicenter about .25 mile away. At the first shock, I thought it was my teen-aged son and yelled at him to knock it off, then the second one came and I realized that it was probably not him.

Svend Ferdinandsen
August 9, 2012 6:46 am

Denmark had also a quake http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/usb000bpam.php
and that is a bit more amazing. I did not felt it as it was very early in the morning, but many reported feeling it.

Brian H
August 9, 2012 8:27 am

kadaka (KD Knoebel) says:
August 8, 2012 at 1:11 pm
u.k.(us) said on August 8, 2012 at 11:37 am:
Here’s a question.
Are “head crashes” a problem for computers during earthquakes ?
If the computer falls off the desk and hits hard while the hard disk drive is in use, sure, it could be.

Back in the day, someone giving a talk on stage moved a PC from one table to another while it was running, and lost grip on one corner just as he was setting it down. It dropped maybe an inch, but the impact seized the HD, and within seconds flames were shooting out the fan vent! I’ve always been careful to power off when moving computers ever since …

Brian H
August 9, 2012 8:32 am

GW is causing the globe to expand, and softening the crust. These little stretch-mark failures are only to be expected.
That’s my theory, and I’m sticking to it! At least for a week or so …

August 9, 2012 8:34 am

Ok, I’m not a geologist. And yet, I have followed arguments about earthquake patterns such as in Asia Minor. The concept is the stress of one earthquake can be transferred to the next segment after the first ruptures.
Lets examine potential and kinetic energy. When the plates are jammed together, building up stress, that is potential energy being created and stored. When the tension becomes too great and the plates snap past each other, that is a release of that energy in the form of kinetic energy. We feel that release in the form of shaking. But once it happens, much of the energy and stress from the locked plate is gone.
Not to the transferred stress. In some sense, that almost certainly does happen. But whatever potential energy remains would be greatly diminished as most of the energy dissipated in the big quake in the form of ground shaking. That said, one can expect that having a plate suddenly move in that fashion would result in some stress being transferred to another nearby sticking point, or even the creation of a new one.
How would this effect the rest of California???? Whatever magnitude quake were talking about, the effect would be localized to the immediate area. Most people think of rock and the earths crush as very hard. Geologists on the other hand recognize that they are very pliable in the grand sense of things. The crust can be incredibly flexible. Look at how it can bend into strange shapes when put under pressure! There is much more give in rock material other solids than most realize. Example, an old glass plain window. If you look and measure a glass window that is more than 100 years old, you’ll find that the glass is thicker at the bottom of the window than at the top. It wasn’t made that way. Glass may be hard, but over time, it flows. The crust, though very hard by our standards, also moves over time. When you are talking about thousands of miles of crust, there is an elasticity built into the system, which is why a medium large quake in Los Angeles is very unlikely to be felt in San Francisco. And the stress from that release would not have much effect on the fault systems in the San Francisco area either.
Have to go work now. Hope this helped.
Mike Alexander…. Geology School Drop-out.

Brian H
August 9, 2012 8:40 am

Michael J Alexander says:
August 9, 2012 at 8:34 am

Example, an old glass plain window. If you look and measure a glass window that is more than 100 years old, you’ll find that the glass is thicker at the bottom of the window than at the top. It wasn’t made that way. Glass may be hard, but over time, it flows.

I do believe that’s an urban legend. The glass was indeed “made that way”. It was blown in as large a bubble as possible, and a piece cut for the window. There was always a thicker edge, and that was placed at the bottom. Flow rates, if any, are orders of magnitude too small for results to be perceptible in the time frames involved.

August 9, 2012 1:33 pm

Michael J Alexander says:
August 9, 2012 at 8:34 am
I can think of two fault systems off of the top of my head where earthquakes tend to “walk” along the fault. One is in Turkey and another in the Carribean, specifically it is the one that released a big earthquake in Haiti a few years ago.

August 9, 2012 11:18 pm

Mark, they move more often because those sections of both plates move more rapidly. On the Haiti fault system, there seems to be a large event every 100 to 150 years.
On the glass thing… It does appear my professor was correct… Partially:
“Like liquids, these disorganized solids can flow, albeit very slowly. Over long periods of time, the molecules making up the glass shift themselves to settle into a more stable, crystallike formation, explains Ediger. The closer the glass is to its glass-transition temperature, the more it shifts; the further away from that changeover point, the slower its molecules move and the more solid it seems.
Whatever flow glass manages, however, does not explain why some antique windows are thicker at the bottom. Other, even older glasses do not share the same melted look. In fact, ancient Egyptian vessels have none of this sagging, says Robert Brill, an antique glass researcher at the Corning Museum of Glass in Corning, N.Y. Furthermore, cathedral glass should not flow because it is hundreds of degrees below its glass-transition temperature, Ediger adds. A mathematical model shows it would take longer than the universe has existed for room temperature cathedral glass to rearrange itself to appear melted.”

So it does shift. But the glass plain does not, and can not, be an example of this…. Unless someone, a climate scientist maybe, comes in and tweaks the models!!! 🙂

August 10, 2012 10:02 pm

This is what it is like living in beautiful Southern Cal!

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