Abstract
Slant stacking of broadband seismograms recorded in the western US for two 1993 intermediate-depth earthquakes that occurred near the Bolivia-Argentina-Chile borders reveals small but clear precursors to both the wave and S wave depth phases. These precursors represent underside reflections from the thickened Andean Altiplano crust. The best-fit model has an average crustal velocity of 5.9-6.0 km/s, a crustal V p /V s of 1.6, a crustal thickness of 75-80 km, and a high-velocity, high-V p /V s mantle wedge. The finding of a thick felsic crust overlying a high-velocity mantle supports models of Altiplano uplift due predominantly to crustal shortening as opposed to mafic magmatic addition and is inconsistent with recent mantle delamination. -from Authors
Original language | English (US) |
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Pages (from-to) | 1003-1006 |
Number of pages | 4 |
Journal | Geology |
Volume | 22 |
Issue number | 11 |
DOIs | |
State | Published - Jan 1 1994 |
ASJC Scopus subject areas
- Geology