Jolie Rouge
03-27-2003, 02:11 PM
By Cathryn Conroy, Netscape News Editor
There's an earthquake rolling underground in the Pacific Northwest right now that is so powerful it's the equivalent of magnitude 6.7 on the Richter scale. But no one can feel it because it's taking place 15 to 30 miles deep into the Earth. Experts call it a "silent" earthquake and expect it to last for weeks instead of the usual seconds-long jolts of a typical quake, reports The Associated Press.
The earthquake began on February 26 beneath the Strait of Juan de Fuca near Friday Harbor, Washington and Victoria, British Columbia--and it's still going strong. Silent quakes, which have only recently been detected using advanced technology and very sensitive instruments, aren't as harmless as they might seem. Scientists worry they are adding to the tremendous pressure in an area where the brittle rocks of two tectonic plates are locked offshore, notes AP. History shows that every few hundred years, those plates release the built-up stress in large, damaging earthquakes of magnitude 8 or 9. The last one occurred about 300 years ago.
This silent quake isn't reducing the stress; instead it's adding to it, according to Herb Dragert, a research scientist with the Geological Survey of Canada in Sidney, British Columbia. AP reports that scientists know now that the silent earthquakes' signals have shown up on seismographs, but they never realized it before because they don't look similar to the signals from regular earthquakes.
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[/i]
Explore the world's major earthquakes with this interactive map. Click on the quake site and see photos and read a description of the damage. [/i]
www.cnn.com/interactive/nature/0009/earthquake.timeline/frameset.exclude.html
There's an earthquake rolling underground in the Pacific Northwest right now that is so powerful it's the equivalent of magnitude 6.7 on the Richter scale. But no one can feel it because it's taking place 15 to 30 miles deep into the Earth. Experts call it a "silent" earthquake and expect it to last for weeks instead of the usual seconds-long jolts of a typical quake, reports The Associated Press.
The earthquake began on February 26 beneath the Strait of Juan de Fuca near Friday Harbor, Washington and Victoria, British Columbia--and it's still going strong. Silent quakes, which have only recently been detected using advanced technology and very sensitive instruments, aren't as harmless as they might seem. Scientists worry they are adding to the tremendous pressure in an area where the brittle rocks of two tectonic plates are locked offshore, notes AP. History shows that every few hundred years, those plates release the built-up stress in large, damaging earthquakes of magnitude 8 or 9. The last one occurred about 300 years ago.
This silent quake isn't reducing the stress; instead it's adding to it, according to Herb Dragert, a research scientist with the Geological Survey of Canada in Sidney, British Columbia. AP reports that scientists know now that the silent earthquakes' signals have shown up on seismographs, but they never realized it before because they don't look similar to the signals from regular earthquakes.
-----------
[/i]
Explore the world's major earthquakes with this interactive map. Click on the quake site and see photos and read a description of the damage. [/i]
www.cnn.com/interactive/nature/0009/earthquake.timeline/frameset.exclude.html