Yes, A Second Major Earthquake

We’re fine, it was a decent distance away. Tonight’s M7.1 quake was about 125 miles away from us, same as the M6.4 quake yesterday.

For those of you who don’t live on shaky ground, that means that for a major quake like that (we’ll see in the morning what’s going on in Ridgecrest and places near the epicenter, but a M7.1 will be knocking down buildings and collapsing bridges) is that here we felt very little of the violent shaking and rattling that you see near the epicenter, but lots of the the rolling and swaying that you get far away.

It’s a matter of physics and geology – check out the CalTech and USGS sites for details. The short version is that the violent, energetic, and largely vertical P-waves don’t travel very far through rock, while the horizontal S-waves with a much higher amplitude do. Then the S-waves damp out as they spread (very much like water waves if you drop a big stone into a calm pool) so 125 miles away you’re likely to feel seasick or dizzy instead of being thrown up against a wall as the bookshelf is falling over and trapping you underneath.

Tonight’s major quake being about eleven times as strong as yesterday’s means that the “oh, is that an earthquake? I think that it probably is!” reaction for 30 seconds or so was supplanted by tonight’s “holy shit, I think this might be getting bigger! sit down and hang on!!!” response for 60 or 90 seconds. Much more adrenaline, the same amount of actual damage. (i.e., NONE)

The scientists at CalTech (who all deserve medals and/or sainthood for dealing with the idiot reporters) always say there’s about a 1 in 20 chance on any earthquake that it will in fact be a foreshock, to be followed by a bigger quake in the next couple of days. Today we hit the jackpot! That’s great – until you hear them saying the same thing about today’s quake having a 1 in 20 chance of being a foreshock of something EVEN BIGGER tomorrow or Sunday.

That would be…exciting.

At least we’re not having any brush fires tonight! Just a couple of really energetic and loud mockingbirds who don’t seem to know that it’s bedtime.

1 in 20, eh? Feeling lucky, punk?