Swarm of 75 Quakes Reported in Yellowstone
Pastor Dale Morgan
Oct 25, 6:32 PM EDT
*Swarm of 75 Quakes Reported in Yellowstone*
YELLOWSTONE NATIONAL PARK, Wyo. (AP) -- A swarm of more than 75 small
earthquakes shook the ground near Old Faithful geyser earlier this
month. The largest was a magnitude 2.4, barely enough to be felt. The
swarm of 75 quakes lasted several hours Oct. 14, according to
information released by the Yellowstone Volcano Observatory.
The tight cluster of earthquakes was moderate compared with others in
Yellowstone's past, including one in April 2004 in which more than 400
earthquakes were recorded over three days.
"It piques our curiosity, but it's not out of the range of normal
behavior," Henry Heasler, Yellowstone's principal geologist, said of the
Oct. 14 activities.
Park officials said the earthquakes were more likely caused by the
underground movement of hot water and gas, rather than the migration of
magma.
The largest swarm recorded in Yellowstone was in the fall of 1985 when
about 1,800 earthquakes were registered, ranging in magnitude from 1 to
4.9. Around the same time, the huge Yellowstone caldera stopped slowly
rising and began slowly falling.
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On the Net:
Yellowstone Volcano Observatory: http://volcanoes.usgs.gov/yvo/