11/8/2023 0 Comments Ran onlinenorth americaThe “Cascadia” part of its name comes from the Cascade Range, a chain of volcanic mountains that follow the same course a hundred or so miles inland. Known as the Cascadia subduction zone, it runs for seven hundred miles off the coast of the Pacific Northwest, beginning near Cape Mendocino, California, continuing along Oregon and Washington, and terminating around Vancouver Island, Canada. Just north of the San Andreas, however, lies another fault line. For the San Andreas, one of the most extensively studied and best understood fault lines in the world, that upper limit is roughly an 8.2-a powerful earthquake, but, because the Richter scale is logarithmic, only six per cent as strong as the 2011 event in Japan. Every fault line has an upper limit to its potency, determined by its length and width, and by how far it can slip. Most people in the United States know just one fault line by name: the San Andreas, which runs nearly the length of California and is perpetually rumored to be on the verge of unleashing “the big one.” That rumor is misleading, no matter what the San Andreas ever does. But for Chris Goldfinger, a paleoseismologist at Oregon State University and one of the world’s leading experts on a little-known fault line, the main quake was itself a kind of foreshock: a preview of another earthquake still to come. The shaking earlier in the week turned out to be the foreshocks of the largest earthquake in the nation’s recorded history. In the end, the magnitude-9.0 Tohoku earthquake and subsequent tsunami killed more than eighteen thousand people, devastated northeast Japan, triggered the meltdown at the Fukushima power plant, and cost an estimated two hundred and twenty billion dollars. Thirty minutes after Goldfinger first stepped outside, he watched the tsunami roll in, in real time, on a two-inch screen. One of them pulled out a cell phone and started streaming videos from the Japanese broadcasting station NHK, shot by helicopters that had flown out to sea soon after the shaking started. Almost immediately, though, it became extremely uncool, because Goldfinger and every other seismologist standing outside in Kashiwa knew what was coming. Now, Goldfinger realized as the shaking hit the four-minute mark, the planet was proving the Japanese Cassandra right.įor a moment, that was pretty cool: a real-time revolution in earthquake science. The presentation was met with polite applause and thereafter largely ignored. In 2005, however, at a conference in Hokudan, a Japanese geologist named Yasutaka Ikeda had argued that the nation should expect a magnitude 9.0 in the near future-with catastrophic consequences, because Japan’s famous earthquake-and-tsunami preparedness, including the height of its sea walls, was based on incorrect science. For decades, seismologists had believed that Japan could not experience an earthquake stronger than magnitude 8.4. Oh, shit, Goldfinger thought, although not in dread, at first: in amazement. His watch swept past the three-minute mark and kept going. He thought better of it, and lurched away. The base was lurching, too, back and forth a foot at a time, digging a trench in the yard. The building itself was base-isolated, a seismic-safety technology in which the body of a structure rests on movable bearings rather than directly on its foundation. The flagpole atop the building he and his colleagues had just vacated was whipping through an arc of forty degrees. The trees, still hung with the previous autumn’s dead leaves, were making a strange rattling sound. It was, Goldfinger thought, like driving through rocky terrain in a vehicle with no shocks, if both the vehicle and the terrain were also on a raft in high seas. The earth snapped and popped and rippled. Nor, from the feel of it, was there ground on the ground. There was a chill in the air, and snow flurries, but no snow on the ground. At a minute and a half, everyone in the room got up and went outside. Goldfinger, who is tall and solidly built, thought, No way am I crouching under one of those for cover. The seats in the conference room were small plastic desks with wheels. Then it ticked past the sixty-second mark, making it longer than the others that week. The earthquake was not particularly strong. The speaker at the lectern was wondering if he should carry on with his talk. The conference was wrapping up for the day. When Goldfinger looked at his watch, it was quarter to three.
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