My First Earthquake April 18, 2008

Given the number of times I’ve been to California, you would think that my first earthquake experience would have been there. It wasn’t. My first was lying in bed, right here in Kentucky.

Thankfully, it doesn’t seem that it was a movie-worthy event.

What Seismologists Say Happened

According to the NOAA, Illinois experienced an earthquake this morning. The epicenter for this geologic event was:

• 12 km (7 miles) E (90°) from West Salem, IL
• 13 km (8 miles) NE (53°) from Bone Gap, IL
• 14 km (9 miles) W (266°) from Allendale, IL
• 67 km (41 miles) NNW (335°) from Evansville, IN
• 206 km (128 miles) E (93°) from St. Louis, MO
• 5 km (3.1 miles) below the ground

The severity was a 5.4 on the Richter Scale. There is much talk on the news about this event and the New Madrid Fault. However, a cursory examination of these locations suggests that this seismic event wasn’t a result of anything along this fault line.*

What I Felt Happen

I was lying in bed, having already awakened, but trying to catch another 30 minutes or so of sleep. Not today.

What happened first was something that I heard, rather than felt. Perhaps I’m strange, but little sounds always get my attention. When one of the boys comes home late, I hear the door open downstairs, but not directly. What I hear is the effect on the walls and the windows from the change in air pressure inside the house. It’s weird, but it happens every time. It’s subtle, but it wakes me up. That’s what happened here.

I heard the same series of sounds that I would typically hear if someone was coming in the back door. That was somewhat startling, because it was around 5:30 AM EST. People don’t usually wander in the back door at that hour… not even the various football players who park in our driveway to walk to the high school.

This first sound was followed by something a bit surreal, which was me sensing the initial low-frequency waves. Whether this was just my mind’s perception of the slight distortion that the house’s foundation was already experiencing, I don’t know. Either way, I sensed that there was something still going on, a couple of seconds after the first sound got my attention.

What followed was a good 20 seconds or so of sustained shaking. They are engaging in some pretty major construction at the adjacent high school, and this was on the same level with what I’ve felt from underground blasting for excavation, except that it had no clearly defined peak. It was as if the entire house was going over some of those rumble strips on the expressway, warning you to slow down.

Then, rather suddenly, it faded out and stopped. The dog, who was clearly a bit unnerved, came into the room a little apprehensively. Always the master of the obvious, I simply stated:

“I think we just had an earthquake.”

What Really Happened

After a bit of consideration, I determined what happened this morning. It was God’s way of saying “Happy Birthday” to my wife.

* Thanks to Sharon Thornton, Research Coordinator at The International Union of Geodesy and Geophysics for updated information and this resource

In addition you can find more info here: An Earthquake Rattles the Midwest.