Experts: Mega-quake, tsunami could happen here

Not only could a disaster like the one that hit Japan Friday happen in the United States - one already has, and could again, experts said on "The Early Show on Saturday Morning."

The magnitude-8.9 shaker spawned a tsunami that swamped large swaths of northeastern Japan, leaving devastating damage and killing hundreds.

And Dr. Marcia McNutt, director of the U.S. Geological Survey, told c-anchor Rebecca Jarvis, "Every time an event like this happens, it's a wake-up call for us here in America that we need to be prepared."

McNutt said the exact scenario that we saw happen in Japan has already occurred, in the Pacific Northwest.

"Brian Atwater, who's a specialist at the U.S. Geological Survey, has looked back into the geologic record and seen evidence that, on the 26th of January, at 9 p.m., in the year 1700, there was an earthquake that generated a tsunami ... offshore Oregon ... that was actually historically recorded in Japan," McNutt said. "It was the same magnitude as this event. It happened then. It could happen again."

Complete coverage: Disaster in Japan

The time frame of such disasters, though, "can be very hard to predict," James Gaherty, seismologist and Lamont associate research professor at Columbia University, pointed out to Jarvis, "because they do vary. The geologic record clearly shows that they vary over time, so putting a precise number on it is very difficult. But you can look at the relative rates of the motion across these kinds of large faults, and try to make an estimate of how much time it will take to accumulate the kind of stress that's going to produce a big earthquake like this.

"In the Pacific Northwest, it's certainly a longer time window for the repeating of these kinds of events than it is in Japan (where events like Friday's are thought to happen once a century). It's probably more in the order of 300-to-500 years."

McNutt observed that, in the U.S., "Like Japan, for decades, we have been using building codes that are up to date. And so, like Japan, I think happily we can say that modern building codes should withstand strong shaking, and strong earthquakes. But, sadly, I think what this event in Japan has shown us is that something like a wall of water that is six feet high, running six miles inland, or even higher, is something that we are equally unprepared for. And that many of the same kinds of preparedness that we're talking about in terms of hardening our communities to floods, and to sea level rise, might be the very same things we should think about accelerating in terms of preparing ourselves for tsunamis."

What parts of the U.S. are most susceptible?

"The most obvious place," Gaherty replied, "is the Pacific Northwest, the coast of Washington and Oregon. And I think one of the real interesting lessons that for me that I think is starting to come out of this earthquake in Japan is that the education of the local citizens, that these kinds of events happen, and how to behave when you feel strong shaking, we don't - the fault in the Pacific Northwest was a little bit different in that we don't generate even smaller events as often as they do in Japan.

"So I think the population there - it's a really important public education effort that needs to be made to make sure the population there knows how to respond when these kind of events occur. Because it sounds like there was significant saving of life, believe it or not, in many parts of the most devastated region (of Japan) because people got into high buildings, were able to get out of the way of the water."

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