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The configuration of the seismic zone and the downgoing slab in southern Peru
Author(s) -
Grange F.,
Cunningham P.,
Gagnepain J.,
Hatzfeld D.,
Molnar P.,
Ocola L.,
Rodrígues A.,
Roecker S. W.,
Stock J. M.,
Suárez G.
Publication year - 1984
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl011i001p00038
Subject(s) - geology , seismology , seismometer , seismic zone , discontinuity (linguistics) , volcano , slab , induced seismicity , geophysics , mathematical analysis , mathematics
Using data from temporary networks of portable seismographs in southern Peru, we located 888 shallow and intermediate depth events near a proposed discontinuity in the seismic zone there. These events reveal a prominent contortion, instead of a discontinuity, that trends approximately N80°E, parallel to the direction of relative plate motion. North of about 15°S, the seismic zone beneath Peru is nearly horizontal, but south of about 15.5°S, it dips at about 25°. Volcanoes lie above the more steeply dipping zone where earthquakes occur between 120 and 140 km, and the volcanic line in southern Peru stops abruptly at the contortion.