Source characteristics of the 12 November 1996 M(w) 7.7 Peru subduction zone earthquake

Jennifer L. Swenson, Susan Beck

Research output: Contribution to journalArticle

31 Scopus citations

Abstract

The 12 November 1996 M(w) 7.7 Peru subduction zone earthquake occurred off the coast of southern Peru, near the intersection of the South American trench and the highest topographical point of the subducting Nazca Ridge. We model the broadband teleseismic P-waveforms from stations in the Global Seismic Network to constrain the source characteristics of this subduction zone earthquake. We have analyzed the vertical component P-waves for this earthquake to constrain the depth, source complexity, seismic moment and rupture characteristics. The seismic moment determined from the nondiffracted P-waves is 3-5 x 1020 N·m, corresponding to a moment magnitude M(w) of 7.6-7.7 The source time function for the 1996 Peru event has three pulses of seismic moment release with a total duration of approximately 45-50 seconds. The largest moment release occurs at approximately 35-40 seconds and is located ~90 km southeast of the rupture initiation. Approximately 70% of the seismic moment was released in the third pulse. We find that the 1996 event reruptured part of the rupture area of the previous event in 1942. The location of the 1996 earthquake corresponds to a region along the Peru coast with the highest uplift rates of marine terraces. This suggests that the uplift may be due to repeated earthquakes such as the 1996 and 1942 events.

Original languageEnglish (US)
Pages (from-to)731-751
Number of pages21
JournalPure and Applied Geophysics
Volume154
Issue number3-4
Publication statusPublished - 1999

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Keywords

  • Historical earthquakes
  • P-waveforms
  • Rupture characteristics
  • Source characteristics
  • Source parameters
  • Source time function

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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