The Threat of Silent Earthquakes.

• Autores: Peter Cervelli
• Localización: Scientific American, ISSN 0036-8733, Vol. 290, Nº. 3, 2004, págs. 86-91
• Idioma: inglés
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• Resumen

  • This article discusses silent earthquakes. In early November 2000 the Big Island of Hawaii experienced its largest earthquake in more than a decade. Some 2,000 cubic kilometers of the southern slope of Kilauea volcano lurched toward the ocean, releasing the energy of a magnitude 5.7 shock. Part of that motion took place under an area where thousands of people stop every day to catch a glimpse of one of the island's most spectacular lava flows. Yet when the earthquake struck, no one noticed--not even seismologists. The chances of catastrophic flank failure are slim, and the instruments that record silent earthquakes might make early warnings possible. Kilauea's network of more than 20 GPS stations, for example, has already revealed that the volcano experiences creep, silent earthquakes as well as large, destructive typical earthquakes. Geologists have long known that water leaking into faults can trigger earthquakes, and nine days is about the same amount of time that they estimate it takes water to work its way down through cracks and pores in Kilauea's fractured basaltic rock to a depth of five kilometers-where the silent earthquake occurred. If future study reveals silent earthquakes to be a common feature of most large faults, then scientists will be forced to revisit long-held doctrines about all earthquakes.