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The Western U.S. and earthquakes: a not-so-peaceful but required coexistence

Recent earthquakes again serve as a reminder to be prepared for "The Big One"
Recent earthquakes again serve as a reminder to be prepared for "The Big One"
Gary London

Residents across the West shouldn't be surprised that earthquakes—numerous in the past few weeks, have been shaking areas from southern California to Yellowstone. Oklahoma got in on the act as well, with a swarm on Sunday, three of which registered greater than 4.0.

Anyone familiar with geography and science—should be able to ascertain the known relationship with mountain ranges and seismic activity. The western United States and California sit atop a series of sliding, slippery motion rich pieces of earth under unceasing pressure by dynamic forces below.

Plate tectonics—the relatively new science of how the earth is divided into moving, grinding segments, explains how the continents and oceanic floors float and drift, pressing against, over and under and sideways against each other. Not far beneath the earth's surface, solid crust gives way to a plastic, molten state of material upon which these segments float, hence ceaseless motion, as little as 1/8 inch per year. But over time, this energy accumulates, particularly if moving regions become locked, or frozen by friction. Stresses build up and tension accumulates, until what is known as 'elastic rebound' finally contributes to a sudden snap, which releases the energy all at once, in the form of an earthquake.

California's well known San Andreas fault, the boundary between the Pacific and North American tectonic plates is only one of potentially thousands of more or less significant faults across western North America. At the same these two plates are slipping laterally past each other, there is what is known as subduction taking place beneath the surface. This is where the Rocky Mountain and Sierra Nevada ranges are being forced upwards as one subsurface block of earth pushes beneath another. Additionally, large regions of the earth's surface are being both stretched apart and compressed, notably ocean floors, and even the state of Nevada.

This constant strain and conflict beneath us—should make it clear that earthquakes—as well as volcanic activity in both the recent and distant past, are as much a part of life as anything else in this as well as other parts of the world. The so-called “Ring of Fire” encompassing much of the Pacific clearly exemplifies this.

It's not that all of a sudden, the earth is shaking beneath us—it's more like in our day to day involvements and priorities, we don't stop to consider what has always been present beneath and around us. Perhaps this is due to the fact that seismic motion and events simply don't operate on the same timetable as human perception and expectation. The reason the western United States is so richly adorned with spectacular splendid and rugged scenic beauty is precisely due to these forces. Forces which have been in operation long before Columbus discovered America. Long before the Bible was written. Long before that.

So stop to consider that yes, we have violent terrestrial activity in our past, present and future. Crater Lake in Oregon, the Cascade and Sierra ranges with their numerous potentially active volcanoes and the thousands of known and unknown faults should make it clear that we are the mercy of these forces, and if nothing else, to be ready when the next major cataclysm comes.

And it no doubt will.

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