Today we’ve experienced a few detectable – human-detectable, I mean – earthquakes in Southern California.
This is always fun when you work in a hi-rise office building. We often estimate the magnitude by the level of noise and groaning from the building. The windows, walls, ceiling and floors all seem to make crackling and popping sounds during an earthquake.
It’s around this time that a low-grade panic begins to set in; on the one hand, you recognize that it is futile or even dangerous to make a run for the stairwell, knowing that if it really starts to shake, you can go tumbling down flights of stairs. It is also more likely than not that you are living through a relatively minor temblor.
On the other hand is the nearly irresistible urge to evacuate a swaying, groaning and popping hi-rise office building before it potentially becomes a pile of rubble – with you still in it.
Often times the building sways back and forth for a minute or so after the shaking stops as well.
On the drive into the office this morning I heard a report of an earthquake last night in the vicinity of Yorba Linda, in northeast Orange County, California, at around 11:30 pm. As we were watching the Olympics at that time, just before bedtime, I can say that we didn’t feel it.
At around 9:30 this morning, while on a conference call with a client and several colleagues, I most certainty DID feel this one:
earthquake map from USGS
Following the action for a while reveals how the aftershocks played out. Notice that the red box, solid above, picks up the smaller aftershocks within about a half an hour (the smaller boxes overlaid on top of the larger one, demonstrating the magnitude of each quake):
aftershocks showing on top of the original quake
Here’s a summary of the shaking, courtesy the US Geological Survey:
lots of aftershocks!
racing to the red light 