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  Seismic Activity - East Pacific Rise at 54 South (December, 1996)  
 

 

 
 
epicenters
(click to enlarge)
Plot of Earthquake Epicenters; Bathymetry is based on satellite altimetry model of Smith and Sandwell.
Estimated error for the site based on a numerical simulation is 35-minutes in latitude and 45-minutes in longitude.
Mean position is 53 42.59' S, 140 23.82' W.
  

Beginning December 1, 1996, the Autonomous Hydrophone Array deployed by PMEL in the Eastern Equatorial Pacific recorded what appears to be volcanic seismicity from the off-axis of the southern extension of the East Pacific Rise near 54 S and 140W. The activity continued for 7 days with a total of 150 events located.

The location is on a volcanic ridge west of the Eltanin Fracture Zone that has produced volcanic seismicity in the past (Talandier and Okal, BSSA,?) . The character of the seismicity is very similar to that observed at 3-20N on the EPR in May, 1996, and other locations on the ridge. It does NOT show the monochromatic (7Hz) nature described by Talandier and Okal.

histogram Histogram of number of earthquakes recorded from the volcanic site per one-hour period. 
 (click to enlarge)

Listing of earthquake epicenters from the EPR at 54 S recorded December, 1996.

 
 
Last Updated: 01/05/01

Address inquiries to:

Robert Dziak - Seismologist - robert.p.dziak@noaa.gov