Earfquake!

Most houses in CA are built to earthquake code – the ones that haven’t already fell down.

Not much - probably nothing. Such long rolling waves provides a lot of displacement, but it’s like the entire structure moves up and down together at once. The worst I’ve ever seen a house flex during an earthquake was a lousy 4.something, but I was one mile from the epicenter (vertically and horizontally). For that one I could see the floor move then the rest of the house ripple along in delayed reaction from the bottom up. It left several long cracks in the plaster. One jolt, and that was it, that last maybe a second or two. Proximity counts for a lot.

This is why you don’t see a lot of basements and if you see brick on a house, it’s backed up by stucco.

Most of the newer ones anyway; a lot of structures are still grandfathered down a bit. If I recall correctly you can get earthquake data and other info tailored for that property before you buy it (maybe it’s required, I don’t know for sure).

Of course if you’re built on landfill there’s not going to be a lot you can do–you’re playing with fire now.

— Alan

Nope, I’ve never seen earthquake data about any property I’ve bought. The building standards that are strictly enforced relate to commercial property much more than regular housing. Many structures have been modified over the years to meet earthquake standards, particularly hi-rises and roadways.

In other news, LA Times/NYT is reporting that the quake happened on the Big Fault, the San Andreas. Clearly though it was not the Big One, thank goodness.

Ah ok I’ll have to find out where I read that and have the author summarily shot. Or my memory. Either way.

— Alan

Base Isolation is the key.

Never had the… er, pleasure, I suppose… of experiencing one of your West Coast temblors, but we occasionally feel very minor quakes up this way. Once every few years or so. Never enough to do much damage, but they do cause the furniture to shake a bit, and sound like a Jake-braking semi going through the yard.

Given the size of the quake, I guess I’m surprised we haven’t heard more about damage south of the border. The articles I’ve seen say the epicenter was only 19 miles from Mexicali, which has a population of close to a million people. And while the US side of the border has better earthquake resistant structures, I don’t think that’s true for south of the border in general. So I’m not going to be surprised if this turns into a bigger story as more emerges from the Mexican side.

Supposedly a parking structure collapse and perhaps more than one large fire in Tijuana but yeah, haven’t heard much. From Mexicali south there doesn’t appear to be a lot in Mexico with immediate access; word of damage will take some time to filter I imagine.

— Alan

Ya there are reports of damage in Mexico as well as in San Diego.

We felt it here north of San Diego. It was fairly long but gentle. I immediately said to my wife “That was a major quake, but the epicenter was at least a couple hundred miles away”–which it was. The interesting thing is that it will put additional strain on the section of the San Andreas that’s about due for an 8-ish magnitude shock. The fault that ruptured was to its south, and the direction of ground motion was to the NW, so the San Andreas proper will feel the effects.

Don’t get me wrong–I’m not saying the Big One hits tomorrow. However, it’s been over 150 years since the Fort Tejon quake, the last major one along the southern San Andreas, and the calculated mean interval for this region is right around 150 years. The effects of earthquakes contributing to additional fault ruptures further down the line are still being investigated, but the correlations look good even though the time periods involved are often (but not always) measured in years, not days. Folks in SoCal who don’t have stocks of water, canned food, and so on might want to go shopping–always good to have a few days worth on hand, at least, in such an unstable region.

Oh, God, right after an earthquake is a great time to go shopping. Bring the Benny Hill theme song with you to play on headphones.

I was at a party when it happened. A guy who moved here four months ago actually crawled under a table until it stopped. We all thought that was pretty funny.

-Tom

Poor guy, a table is about the worst place you can go, at least that’s what they taught us in grade school. Hopefully someone told him to go to a door jamb next time.

Nah, I just completed my usual Sunday evening grocery run a couple hours ago. Store was deserted.

DO NOT stand in a doorway: An enduring earthquake image of California is a collapsed adobe home with the door frame as the only standing part. From this came our belief that a doorway is the safest place to be during an earthquake. True- if you live in an old, unreinforced adobe house or some older woodframe houses. In modern houses, doorways are no stronger than any other part of the house, and the doorway does not protect you from the most likely source of injury- falling or flying objects. You also may not be able to brace yourself in the door during strong shaking. You are safer under a table.

http://www.earthquakecountry.info/dropcoverholdon/

Apparently you’re just not safe anywhere. A guy in Mexico ran out into the street and got hit by a car.

— Alan

I grew up in one of the aforementioned older wooden framed houses, but you learn something new every day!

Running into the street during a strong quake is about the dumbest thing you could possibly do.