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 Iowa City, IA Press Citizen Editorial page — January 18, 2005 Could It Happen Here?By Bill Asenjo, PhDThe 400 residents of New Madrid, Missouri awoke to violent shaking and a tremendous roar — the first of three of the most powerful earthquakes in U.S. history (magnitude-8) and thousands of aftershocks. It was December 16, 1811. Crewmembers on the Mississippi steamboat New Orleans reported mooring to an island only to see it disappear beneath the Mississippi River. Damage occurred as far away as Charleston, South Carolina, and Washington, D.C. Even before the recent magnitude-9 monster beneath the Indian Ocean, earthquakes were on my mind. Last summer I was up late reading — it was just after 1AM, when I felt a jolt. Everything shuddered. I thought someone had driven a car into the tree outside my window. Little did I realize it was a 4.5 quake, roughly 130 miles east of Iowa City in the Ottawa, IL area just off 1-80. The quake was felt in northern Illinois, southeastern Iowa, southern Wisconsin, near Detroit, Michigan, northwestern Indiana, and parts of northeastern, Missouri. There were no reports of damage. According to the U.S. Geological Survey, there are at least 500,000 earthquakes each year worldwide — but only about 100,000 of those would rattle the dishes in your kitchen. Fortunately, barely 100 cause damage. The U.S. is no stranger to earthquakes. But not all U.S. quakes are quite the same. Earthquakes in the central and eastern United States affect much larger areas than earthquakes of similar magnitude in western states. For example, San Francisco's 1906 quake (magnitude 7.8) could be felt 350 miles away in Nevada, whereas the New Madrid earthquake of 1811 (magnitude 8) rang church bells in Boston, a thousand miles away. Differences in geology east and west of the Rocky Mountains account for the contrast. Destruction from recent moderate earthquakes emphasizes the need for preparation. For example, California's 1994 magnitude-6.7 quake cost 33 lives and $20 billion, and Japan's 1995 magnitude-6.9 quake cost 5500 lives and $100 billion. Although the central Mississippi Valley of 1811 was sparsely populated, today the region is home to large cities like St. Louis and Memphis. Disturbingly, most structures in the Midwest have not been built to withstand a quake's destructive force, as they are in California and Japan. Earthquakes of moderate magnitude happen more frequently than powerful earthquakes. Scientists estimate that the probability of a magnitude 6 or 7 earthquake occurring in the central Mississippi Valley during the next 50 years is higher than 90%. Indonesia and Iowa City may be on opposite sides of the world. But are we really that far removed from a similar experience? Reach Bill Asenjo, who teaches freelance writing students online and at Kirkwood Community College and who completed his doctorate at the University of Iowa in 2001, at basenjo@avalon.net. Sources: U.S. Geological Survey Recent Midwest Quakes — http://www.eas.slu.edu/Earthquake_Center/NEW/localmaps.html © 2009 Bill Asenjo |