Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by BOYD, T. M. Articles by RODRIGUEZ B., A. Search for Related Content GeoRef GeoRef Citation

High-resolution determination of the Benioff zone geometry beneath southern Peru

VIRGINIA TECH SEISMOLOGICAL OBSERVATORY DEPARTMENT OF GEOLOGICAL SCIENCES VIRGINIA POLYTECHNIC INSTITUTE AND STATE UNIVERSITY, BLACKSBURG, VIRGINIA 24061
DEPARTMENT OF TERRESTRIAL MAGNETISM CARNEGIE INSTITUTION OF WASHINGTON, WASHINGTON, D.C. 20015
CHARACATO GEOPHYSICAL OBSERVATORY SAN AUGUSTIN UNIVERSITY, AREQUIPA, Peru

Abstract

The Benioff zone geometry beneath southern Peru is determined using 32 months of arrival-time data from a local seismic network. Our data set includes 2476 located events, of which 205 are chosen to be master events; earthquakes with the most reliable locations. All the events are then relocated using sourceregion dependent station corrections derived from the station residuals of the master events. We find that the Benioff zone in the more southerly region of our study area dips at a nearly constant 30° to a depth of at least 200 km, while in the more northerly region this trend is apparent down to a depth of only 100 km, at which depth the Benioff zone becomes nearly horizontal. There are enough earthquakes in our data set in the transition zone between the regions to show conclusively that the deformation of the Benioff zone is continuous; i.e., there is no discontinuity in the seismicity that might suggest a tear in the subducting plate. These results corroborate those of Hasegawa and Sacks (1981) which used only about a third of the data now available.

Footnotes

^* Present address: Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964.

This article has been cited by other articles:

				C. J. Langer and W. Spence The 1974 Peru earthquake series Bulletin of the Seismological Society of America, June 1, 1995; 85(3): 665 - 687. [Abstract] [PDF]