Thursday, October 12, 2006

Do earthquakes happen more frequently in any particular weather?

Who's asking: Anna Bragdon

You may have seen something in the news about a small earthquake off the Maine coast last week. I didn't feel it in Gardiner, but Anna felt it in Bangor, and things fell off shelves as far west as Waterville.

It's the second small earthquake since I moved to Maine, and I must say it's a little exasperating. In Los Angeles, I used museum wax to keep glass bowls from falling off shelves, and my bookcases were anchored to the walls; it never occurred to me that I might need those things in Maine.

Anyway, Anna asked whether earthquakes were more likely to occur in any particular sort of weather. The official answer to that is no; geologists say there's no such thing as "earthquake weather."

People in southern California, however, will tell you that they associate a certain heaviness in the air -- a sort of flat, stagnant heat -- with earthquakes. T.L. Lankford describes it well in his excellent crime novel, Earthquake Weather.

They say animals can feel ultrasound waves before an earthquake, and my stomach felt sour and hollow just before the one real earthquake I experienced (a 4.2 shaker centered in Westwood, in September 2001). Then again, that earthquake happened on a Sunday, and I don't really remember what I'd been doing the night before...

The question that remains open is whether earthquakes affect weather patterns after the event. Last week's earthquake caused a major drop in the water table in some parts of the state, and you have to figure that has some slight effect on the weather. I don't know how you'd go about quantifying that, but maybe someone who knows more will stumble on this post and elaborate in the comments section.


Brendan said...

Dunno if you'll see this comment - I found this old post just now by googling the phrase "earthquakes happen at night" (which I'm fairly certain isn't disproportionately true; I was just wondering if I could find any sources on the Internet that claim it's true, or that debunk the idea that it's true).

Anyway, I am also a California expatriate (I live in Tennessee now) who experienced that September 2001 earthquake. I always remember the date because it was two days before 9/11. Anyway, I was at USC in the Doheny Library bookstacks at the time, which was kind of scary! I told the story of it on my blog, in the wake of today's Midwest quake:

AnswerGirl said...

Thanks for stopping by, Brendan! I have gotten that question about earthquakes at night several times -- the answer to that is no, we just notice them more at night because we're not in motion ourselves. I was once in a car on the Golden Gate Bridge during a small earthquake, and we were unaware of it until we got to the restaurant in Sausalito.

That Westwood/Beverly Hills earthquake was pretty dramatic. I was working alone at The Mystery Bookstore, which has freestanding bookshelves on the floor; several rows of books fell over, and I had a fair amount of cleaning up to do. When I got home, I discovered my TV had fallen off its shelf, but didn't break because it just happened to bounce off a floor cushion.

My dog was VERY upset, though.