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The big one. It may not be imminent, but it is inevitable. The greatest
earthquake hazard exists where one tectonic plate collides with, grinds
past, or dives under another. Plate subduction under Alaska and southwestern
Mexico make them the continent’s most quake-prone spots, with each
having many more strong temblors than California. California’s San
Andreas Fault is also an active seismic zone. The Cascadia subduction
zone potentially could produce quakes stronger than those from California’s
faults, threatening cities in the Pacific Northwest. The Cascadia zone
also makes people on Canada’s west coast that nation’s most
at-risk group. Though less seismically active, the East has also felt
huge quakes. Because eastern underground rock is more rigid than that
in the West, seismic waves travel farther. A repeat of the 1811-12 quakes
in Missouri, which ranged from 7.8 to 8.1 in magnitude, could cause damage
from St. Louis to Memphis.
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Illustrations
courtesy of The National Geographical Society –
illustrations created by Rob Woods of Woods Ronsaville Harlin, Inc.
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