Precursory transient slip during the 2001 M_w = 8.4 Peru earthquake sequence from continuous GPS

Authors

Timothy I. Melbourne, Central Washington UniversityFollow
Frank H. Webb, California Institute of Technology

Document Type

Article

Department or Administrative Unit

Geological Sciences

Publication Date

2002

Abstract

Two-hour position estimates from a continuous GPS station located at Arequipa, Peru, document precursory deformation beginning 18 hours prior to an M_w = 7.6 aftershock of the June 23rd 2001 M_w = 8.4 earthquake. This preseismic signal appears on the north and east components as a slow displacement with an amplitude twice that of the subsequent coseismic. Analysis of three years of 18-hour rate measurement shows this signal to be unprecedented and beyond four standard deviations from the mean rate. The best fitting centroid is directionally consistent with slow slip along the plate interface and suggests the preseismic deformation arises from creep near the aftershock rupture. This implies the Nazca-South American plate interface slipped slowly prior to seismogenic faulting. These observations indicate the M_w = 7.6 earthquake grew out of slow slip along the plate interface and clearly demonstrate the breadth of slip rates accommodated by subduction zone plate interfaces.

Recommended Citation

Melbourne, T. & Webb, F. (2002). Precursory transient slip during the 2001 M_w = 8.4 Peru earthquake sequence from continuous GPS. Geophysical Research Letters, 29(21), 2032. DOI: 10.1029/2002GL015533

Journal

Geophysical Research Letters

Rights

Copyright © 2002 the American Geophysical Union