Wednesday, March 3, 2010

Big quake question:Are they getting worse...?;Seismic shockers are to be expected,but planet seems to be more active

This color-coded map shows earthquakes that have been recorded over the previous seven days. The size of the box indicates the quake's strength, and the color indicates how recently the quake occurred. Notable quakes include the cluster of red boxes in Chile, and the blue box indicating a seismic event in Japan.(USGS)
Chile is on a hotspot of sorts for earthquake activity. And so the 8.8-magnitude temblor that shook the region overnight was not a surprise, historically speaking. Nor was it outside the realm of normal, scientists say, even though it comes on the heels of other major earthquakes.
One scientist, however, says that relative to the time period from the mid-1970s to the mid-1990s, Earth has been more active over the past 15 years or so.
The Chilean earthquake, and the tsunami it spawned, originated on a hot spot known as a subduction zone, where one plate of Earth's crust dives under another. It's part of the active "Ring of Fire," a zone of major crustal plate clashes that surround the Pacific Ocean...

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