Cases of regular intervals between earthquakes of similar amplitudes have been noted in other places, including Hawaii, but these are the exception, not the rule. Much more often, recurrence intervals are given on average with major margins of error. For areas subject to large earthquakes, these intervals can be on the scale of hundreds of years, with bars of uncertainty which also extend over hundreds of years. Obviously, this forecasting method is far from an exact science.
Tom Heaton, geophysicist in Caltech and former senior scientist of the USGS, is skeptical that we could never predict earthquakes. He deals with them largely as stochastic processes, which means that we can attach probabilities to events, but we cannot predict them with precision.
“In terms of physics, it’s a chaotic system,” says Heaton. Underlying everything is significant proof that the behavior of the earth is ordered and deterministic. But without a good knowledge of what is happening under the ground, it is impossible to intuate any sense of this order. “Sometimes when you say the word” chaos “, people think that (you) means that it is a random system,” he said. “Chaotic means that it is so complicated that you cannot do any predictions.”
But as the understanding of scientists of what is happening inside the crust of the earth evolves and that their tools become more advanced, it is not unreasonable to expect their ability to make predictions s ‘will improve.
Slow Shakes
Given what extent we can quantify what is happening inside the planet, it is logical that the prediction of the earthquake has long seemed out of the question. But in the early 2000s, two discoveries began to open the possibility.
First, seismologists discovered a strange and low amplitude Seismic signal In a tectonic region in southwest Japan. It would last from a few hours to several weeks and would occur at somewhat regular intervals; It was not like everything they had seen before. They called it tectonic trecor.
Meanwhile, the geodesists studying the Subduction area of the Cascadia, a massive section off the northwest coasts of the American Pacific where a plate plunges under another, found proof of moments when part of the crust moved slowly in the opposite of his usual management. This phenomenon, nicknamed a slow sliding event, occurred in a thin section of the earth’s crust located under the area which produces regular earthquakes, where higher temperatures and pressures have more impact on behavior rocks and the way they interact.
Student scientists Cascadia also observed the same type of signal that had been found in Japan and determined that he was performing at the same time and in the same place as these slow sliding events. A new type of earthquake had been discovered. Like regular earthquakes, these transitional events – jumping earthquakes – redistribute stress in the crust, but they can take place on all kinds of time ladders, a few seconds. In some cases, as in Cascadia, they occur regularly, but in other areas, they are isolated incidents.