Multiarray rupture imaging of the devastating 2015 Gorkha, Nepal, earthquake sequence

Hao Zhang*, Suzan Van Der Lee, Zengxi Ge

*Corresponding author for this work

Research output: Contribution to journalArticle

25 Scopus citations

Abstract

A rapid, robust multiarray backprojection method was applied to image the rupture pattern of the 2015 Gorkha, Nepal Mw7.8 main shock and its Mw7.3 aftershock. Backprojected teleseismic P wave trains from three regional seismic arrays in Europe, Australia, and Alaska show that both earthquakes ruptured unilaterally and primarily eastward, with rupture speeds potentially decreasing with depth. The rupture of the main shock first extended ESEward at ∼3.5 km/s over ∼120 km, with later rupture propagation further downdip on the eastern segment at ∼2.1 km/s. The aftershock ruptured the fault SE of the main shock's ruptured plane. It began to rupture updipward for ∼20 km at a speed around 1.2 km/s, then it may have accelerated to 3.5 km/s for the next 50 km. The apparent depth-dependent rupture speeds of the two earthquakes may be caused by along-dip heterogeneities in fault strength, with a higher stress concentration on the updip part of the Nepalese Main Himalayan Thrust.

Original languageEnglish (US)
Pages (from-to)584-591
Number of pages8
JournalGeophysical Research Letters
Volume43
Issue number2
DOIs
StatePublished - Jan 28 2016

Keywords

  • 2015 Nepal earthquake
  • Tibetan Plateau
  • depth-dependent rupture velocity
  • multiarray backprojection
  • rupture process
  • stress heterogeneity

ASJC Scopus subject areas

  • Geophysics
  • Earth and Planetary Sciences(all)

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