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The 25 October 2010 Mentawai tsunami earthquake, from real‐time discriminants, finite‐fault rupture, and tsunami excitation
Author(s) -
Newman Andrew V.,
Hayes Gavin,
Wei Yong,
Convers Jaime
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl046498
Subject(s) - seismology , geology , fault (geology) , excitation , geodesy , physics , quantum mechanics
The moment magnitude 7.8 earthquake that struck offshore the Mentawai islands in western Indonesia on 25 October 2010 created a locally large tsunami that caused more than 400 human causalities. We identify this earthquake as a rare slow‐source tsunami earthquake based on: 1) disproportionately large tsunami waves; 2) excessive rupture duration near 125 s; 3) predominantly shallow, near‐trench slip determined through finite‐fault modeling; and 4) deficiencies in energy‐to‐moment and energy‐to‐duration‐cubed ratios, the latter in near‐real time. We detail the real‐time solutions that identified the slow‐nature of this event, and evaluate how regional reductions in crustal rigidity along the shallow trench as determined by reduced rupture velocity contributed to increased slip, causing the 5–9 m local tsunami runup and observed transoceanic wave heights observed 1600 km to the southeast.