Seasonal variations of seismicity and geodetic strain in the Himalaya induced by surface hydrology

Pierre Bettinelli, Jean Philippe Avouac, Mireille Flouzat, Laurent Bollinger, Guillaume Ramillien, Sudhir Rajaure, Som Sapkota

Research output: Contribution to journalArticle

141 Citations (Scopus)

Abstract

One way to probe earthquake nucleation processes and the relation between stress buildup and seismicity is to analyze the sensitivity of seismicity to stress perturbations. Here, we report evidence for seasonal strain and stress (~ 2-4 kPa) variations in the Nepal Himalaya, induced by water storage variations which correlate with seasonal variations of seismicity. The seismicity rate is twice as high in the winter as in the summer, and correlates with stress rate variations. We infer ~ 10-20 kPa/yr interseismic stress buildup within the seismicity cluster along the high Himalaya front. Given that Earth tides exert little influence on Himalayan seismicity, the correlated seasonal variation of stress and seismicity indicates that the duration of earthquake nucleation in the Himalaya is of the order of days to month, placing constraints on faults friction laws. The unusual sensitivity of seismicity to small stress changes in the Himalaya might be due to high pore pressure at seismogenic depth.

Original languageEnglish
Pages (from-to)332-344
Number of pages13
JournalEarth and Planetary Science Letters
Volume266
Issue number3-4
DOIs
Publication statusPublished - 29 Feb 2008

Keywords

  • geodesy
  • Himalaya
  • hydrology
  • seismology
  • tectonics

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