Mr. Geist, thanks for your time. Good evening.
ERIC GEIST, GEOPHYSICIST, U.S. GEOLOGICAL SURVEY: Thank you.
OLBERMANN: Let‘s start with the top theory in the—in the east, if you. That American nuclear or electromagnetic testing that set off the earthquake that unleashed the tsunami like in the “Superman” movie. Is there any evidence that nuclear testing can induce earthquakes?
GEIST: Well, for a little background, this kind of falls into a specialized field called induced seismology. And behind all these theories, I think there‘s a little bit of science involved.
Certainly, the one we can go back to is the Amchitka (ph) nuclear test that occurred in the Aleutian Islands back in 1965 and 1971.
And in general, I think humans can cause very limited changes in stress in the crust, induce very small, localized earthquakes. However, it‘s a real question of scale, going from these small events that humans can cause to major earthquakes such as a magnitude 9 earthquake that occurred on December 26.
OLBERMANN: The other one that we‘ve seen a lot on the Internet locally, the idea that it was not nuclear testing but some sort of big oil hunt for reserves under the Indian Ocean using sonar or radar or both.
Is there any evidence that concentrated sound waves could induce earthquakes or seismic activity of any kind?
GEIST: Well, in terms of what typically goes on in seismic exploration for these oil fields, what they‘re trying to do is to get a very fine picture of the layering of sediments in the earth.
So in order to do that, you don‘t need a really big source like an earthquake to do that. You need, actually, a very sensitive source.
So I think that there is probably the least likely that these controlled source explosions, or air gun blasts in the ocean, can actually trigger an earthquake. They‘re much more finely tuned in order to pick up very fine layering in the sediments.
OLBERMANN: The last question, the limited seismic activity that you talked about, that man have records of bringing on, those occur with—explain the process by which and the degree to which seismic activity results.
GEIST: OK. It‘s a good question, because generally, they fall in a couple of categories. One is when you‘re constructing very large dams. You‘re affecting the stress or the pressure on the earth from the weight of that water.
Similarly, with classic cases in 1960 in the Rocky Mountain Arsenal near Denver, you‘re pumping high pressure fluid three and a half kilometers down in the earth. So you‘re affecting the stresses over small regions, or very shallow in the crust.
And if there‘s any nearby faults, they can be loaded sometimes so that they‘ll slip and trigger an earthquake, or they can either be clamped down and actually reduce the likelihood of earthquakes.
But again, these are all happening in very shallow in the earth, and major subduction earthquakes where you have the Indian Ocean plate going beneath Asia, that‘s occurring at a much deeper depth. Thirty kilometers was the depth of this earthquake.
So there‘s a big gap between what man can cause and the natural processes of the tectonic movement of these plates.
OLBERMANN: Yes, if there‘s any human out there who can cause a 9.0 earthquake, we‘d all better go to his house and worship him.
Eric Geist of the U.S. Geological Survey, great thanks for your time and your insights, sir.
GEIST: Thank you very much.
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