Physics
Seminar
Wednesday,
3/2/2005, 4:30 pm
Willet Science Center 101
Leland Timothy Long |
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Earthquakes and Seismometers |
Georgia
is not noted for its earthquakes.
However, Georgians have experienced many smaller events and some of the
larger eastern United States earthquakes.
Consequently, seismic monitoring has been minimal in Georgia. The early earthquakes are documented by felt
reports only. It was not until the early
1960s that instrumental recording of Georgia’s earthquakes was made possible by
the construction of WWSSN station ATL, 27 miles south of Atlanta. In the early 1970s a variety of portable
instruments were used to document microearthquakes. Then with the construction of dams and the licensing of Nuclear
Power Plants, parts of Georgia, along with parts of neighboring South Carolina,
Alabama, and Tennessee were monitored with up to 50 short period (1.0 Hz)
telemetry systems. When funding for
these from the NRC died out in the 1980s, monitoring was transferred to the
USGS and the existing stations were replaced by a more modern, but sparse,
network of broad-band seismic stations.
Only one, GOGA, operates in Georgia.
In the late 1990s an educational seismometer program was initiated and
there are now about 8 operating seismometers in Georgia’s high schools and
colleges. In the future (6-10 years),
the U.S. Array network will visit Georgia and cover the state with seismometers
every 70 km. These systems in
combination with an anticipated increase in educational seismometers will
vastly improve the seismic coverage and ability to image the crust and upper
mantle under Georgia.
Please join us for light refreshments at 4:15pm
outside WSC 109.