By Sean Carroll | July 30, 2008 12:18 pm

I had just stepped out of the shower yesterday (getting a bit of a late start, yes) when the building began to shake. We’re on the ninth floor of a twelve-story building in downtown Los Angeles, so it was quite exciting there for a while — the ground shook for maybe twenty seconds, the cat scampered under the bed, and an item or two had to be rescued from imminent spillage off of bookshelves. (Our cat has her own blog, so it usually takes quite a shock to drag her away from the internets.)

But a minor earthquake overall, just 5.4 on the Richter scale. No significant damage, even closer to the center (we were about 30 miles away). The interesting thing is that within seconds after the event you could hop to the US Geological Survey page to find a map of all the world’s recent earthquakes, and then home in on this one. Obviously most of the information is computer generated, although the main page for the earthquake does reassure you that “This event has been reviewed by a seismologist.”

So you can check out the Shake Map, of course:

We’re right on top of the dot labeled “Los Angeles.” But you can also find Google maps, travel times for the shocks,

and of course — waveforms!

Earthquakes are so much better with science. The only downside is that I spent the immediate aftermath looking for the kitty rather than drying my hair, so I went through the rest of the day with the dreaded “earthquake hair.”

CATEGORIZED UNDER: Personal, Science
  • Tyler

    earthquake hair goes better with pictures, sean ;o)

    glad everyone is ok down there

  • Tyler

    oh and if you’re up for it, anyone, I was surprised to see this


    and wonder, if the problem is not simply with the detectors or experimental design, what are the implications? it seems they’d be rather profound. I’m sure the crackpots will have all kinds of colorful suggestions, but what I’m really interested in is, what is the least disruptive (to current models) explanation?

    If the second commenter on that article is correct, perhaps this is not as unexpected as the blog post makes it sound, though.

    Sorry to barge into your thread, but this is my go-to source for physics WTF moments ;o)

  • Pingback: regarding recent earthquakes | orbis quintus()

  • Sili

    I’ll put up Emily Lakdawalla’s post here too.

    If you were around, please take a moment to tell the Geological Survey how strongly the quake were felt for you. Even if you didn’t feel it. I’m sure every datapoint helps.

  • Count Iblis

    Tyler, it means that we don’t have to worry about being shaken by a spacequake :)

  • Scott S

    Is it normal or odd, that in the diagram, away from the center of the quake, near Northridge, there is some stronger (yellowish) area? Just curious.

    Finally a question for “Ask-A-Geologist” on the USGS website!

  • http://blogs.discovermagazine.com/cosmicvariance/sean/ Sean

    Message being sent around to Caltech people:

    TO: The Campus Community
    FROM: Dean Currie, Vice President for Business and Finance

    RE: Update on Yesterday’s Earthquake

    In the spirit of a quick update on yesterday’s earthquake:

    Caltech had no injuries. We had some chemical spills that required temporary evacuation in at least one building. We had minor damage, including broken water pipes in Noyes and in the Cogen plant. Four elevators went temporarily off line. The campus responded as you would have hoped. Everyone did their part – from the daycare center to the environmental health and safety group, facilities, computing and telecommunications, to individuals in all the buildings and labs, and to HR for the notice to be thoughtful of those employees whose homes were closer to the epicenter.

    I assume that it was by coincidence that, at the time of the earthquake, the Caltech Trustees were being given a tour of the Seismological Lab. I am told that they were impressed. Public Relations and the Seismo Lab must have been busy. I counted 10 media trucks parked outside as I left campus last night.

  • JCF

    Rocked the house and rattled the windows here in San Diego, just south of UCSD campus. SoCal has been lucky; the bad news has been the horrific epidemic of forest fires to the north, one now threatening Yosemite.

  • http://www.pieter-kok.staff.shef.ac.uk Pieter Kok

    Phil Plait had a nice post about it, too.

  • Lawrence B. Crowell

    It is funny about your cat. My cat and I had, the cat has since gone to the happy mouse hunting grounds, a sort of adversarial play relationship. Getting the cat to jump up with a start was always fun. Sounds like the quake did that for you.

    Lawrence B. Crowell

  • http://lablemminglounge.blogspot.com Lab Lemming

    The color map shown by Sean denotes ground shaking, which is a function of earthquake energy and local geologic conditions such as soil type. Areas with poorly compacted soil generally shake more. So if you can find a soil map of the LA basin, that might provide a clue as to why the shaking was greater is certain areas.

    And if y’all like graphs and waveforms, just wait for the big one- earthquakes with M > 8 can excite the free oscillation modes of the Earth.

  • Scott S

    Lab Lemming,
    Thanks for the explanation, I suspected something like that, but it has been many years since took geology. As far as waiting for a M > 8, I love science and all, but I think skip the quake experiment. Living near New Madrid, Missouri, we have enough concerns with our own “big one”. In addition, I don’t want CA to have a large quake, since the rest of country seems to follow CA lead.

    BTW, love the cat’s blog, better writing then most.

  • Lawrence B. Crowell

    Scott: Life seems to be filled with these things. No matter what you do the world is dynamic and it has a way of throwing banana peels in our paths. The one Earth system which I have intimate contact with are tornados. I have seen several of them, and I have been in two, one where I was in a car that got lifted up by the thing. They might seek me out — or at least it seems that way. Maybe I shouldn’t move to the gulf coast, the bigger cousin of the tornado called the hurricane might cme after me. Yet in a way these things do serve a good purpose for us. They tell us how really small and ultimately impotent we are. The only real power we have is a sort of virtual power, which is that of our mind.

    Lawrence B. Crowell

  • Scott S

    Just to close the loop on the Northridge question, I did use USGS’ Ask-A-Geologist and got a quick and informative answer back. (see below)

    excuse me for the very bad pun, but the “USGS rocks!” I love being able to ask an expert.

    Thanks for contacting Ask-A-Geologist.

    I looked at the shakemaps for the event. I believe it is a combination of a couple of things. First, I believe it is real in that the intensity in Northridge was probably a little higher than the surrounding area because of amplification caused by soft soils in the basin in and around Northridge. This is a very common phenomena. The instrumentation may also be better there than in the intervening mountainous area between Northridge and the epicentral area, but the lower values would also be expected on bedrock as opposed to soft soils. Also, part of the information for shakemap is often generated by individuals reporting their experiences on the “Did you feel it” reporting website. However, I suspect that this map is more instrumentation driven than from subjective descriptions.

  • Xenophage

    Good news: Caltech’s tall thin Milliken Library was built fully instrumented from the inside outward. That temblor awarded somebody a thesis.

    Bad news: The heroic (and heroically expensive) Parkfield installation is still waiting for something to happen locally. The model, the model… needs another parameter.

  • http://lablemminglounge.blogspot.com Lab Lemming

    The parkfield quake finally happened in 2004…


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Cosmic Variance

Random samplings from a universe of ideas.

About Sean Carroll

Sean Carroll is a Senior Research Associate in the Department of Physics at the California Institute of Technology. His research interests include theoretical aspects of cosmology, field theory, and gravitation. His most recent book is The Particle at the End of the Universe, about the Large Hadron Collider and the search for the Higgs boson. Here are some of his favorite blog posts, home page, and email: carroll [at] cosmicvariance.com .


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