Wednesday, February 10, 2010

Earthquake? In Illinois?

I know, ho-hum to you left coasters, but we don't get 'em here except for this morning.

I was sleeping on the couch, and a very loud boom woke me up. I sat up, and everything shook back and forth for about ten seconds, maybe three times per second, picking back up once before dying out. I was aligned roughly in the direction of the quake as I sat up, so it was to-and-fro shaking as I felt it, not side to side.

U.S. Geological Survey site put the epicenter about nine miles WSW of me, at a very shallow depth of 3.5 miles.

By the way, when the shaking stopped I rolled over and went back to sleep, thinking, "I'll have to remember to check if that was an earthquake," but distant relatives called me bright and early to check on it. Oh, ya, I said.

No aftershocks, as for now.

7 comments:

KenP said...

I slept through whatever quivers reach here. My dog took notice though and woke me.

We're part of the New Madrid fault. It occasionally gets shaky and can get nasty. The depth of the fault and the soil can do nasty things. If you dial into the Wayback Machine, you'll see it even stopped the Mississippi River in it's track and rerouted it.

Haley said...

Yep, I'm familiar with the New Madrid fault history. There's a parallel one called the Wabash Valley Fault that was responsible for the 5-whatever So. Indiana quake a few years back.

USGS downgraded it to 3.8, though it seems there's not much for seismographs this far north of New Madrid and they likely have some approximation built in. What I felt matched neatly to about a 4.0 trembler accordingly to the survey I filled out there.

Haley said...

One of the guys I work with locally on occasion just called me -- he lives in Sycamore, like a mile from the epicenter. He verified the loud boom, too, as did another person who I spoke this morning who was awake and has previous experience as a Kane County emergency response.

What's odd is after I went back to sleep I had strange dreams like being in a lightning storm and hearing cracks of thunder. That boom was different than any other I've ever heard and it must have been getting bounced around in my head somehow as I slept. I sleep with a window open even in winter because my apartment habitually overheats, but I've trained myself to recognize and sleep through most of the other loud noises.

Haley said...

Another update: Seems it was not the New Madrid fault line. Early reports suggest that this was on an unrecognized, minor fault connected perpendicular to the Sandwich fault, which runs across north-central Illinois and kicks off occasional earthquakes at that 3-4 mile depth.

Reading up on old history shows that there have been at least four earthquakes in Kane County in the 3.5-4.0 range, which equals a fairly busy week by L.A. standards. The original drilling specifications for the nearby Fermilab (which are online) talk briefly about the Sandwich Fault.

Haley said...

Four Kane Co. earthquakes since 1940, my bad.

Anonymous said...

We are all highly anticipating your next post on AP/UB, Haley. In the meantime I've got you bookmarked :)

Steve Kammerman said...

Wow, good to know it's not just us in California worried about falling off the mainland into the sea. Between the crazy snow on the east coast and now a Midwest earthquake, it sure has been a weird winter in terms of natural occurrences.