200 Years Later: The New Madrid Earthquakes

The most terrifying 45 seconds of my life were spent in the middle of an undulating street in downtown Seattle, Washington, watching skyscrapers sway back and forth like trees in the wind.  The "Nisqually" earthquake, which registered 6.8 on the Richter Scale, occurred on February 28, 2001, which happened to be my 46th birthday.  Moments before running out into the streets to protect myself from falling glass, I was  just sitting on a bench in front of the Westin Hotel, waiting for a shuttle bus to take me to SeaTac airport for my flight back to St. Louis.

I'll post details of that wild experience, some other time.  The point I'd like to get across today is that the event made a very strong impression on me.  In fact, it scared the hell out of me.  It also created an immediate thirst for knowledge about the actual magnitude of the New Madrid earthquakes.  After seeing and feeling the frightening power of a major earthquake, I was very curious about just how much more powerful they could be... especially when the New Madrid fault runs through the state in which I live.  

The answer?  Well... one of the New Madrid earthquakes (8.8 on the Richter Scale) had an approximate "seismic energy yield" of 240 megatons of TNT, which is 1,000 times greater than the 240 kiloton yield of  the Nisqually earthquake that I witnessed.  That magnitude is simply unimaginable to me and I can only hope that our region is a fraction as prepared as Seattle was, for a major earthquake.  Steve Erdelen

Read more about the New Madrid earthquakes here:
http://www.britannica.com/EBchecked/topic/1421133/New-Madrid-earthquakes-of-1811-12