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Was the 9 October 1995 M w 8 Jalisco, Mexico, Earthquake a Near‐Trench Event?
Author(s) -
Hjörleifsdóttir Vala,
SánchezReyes H. S.,
RuizAngulo Angel,
RamírezHerrera Maria Teresa,
CastilloAja Rocio,
Singh Shri Krishna,
Ji Chen
Publication year - 2018
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2017jb014899
Subject(s) - trench , seismology , slip (aerodynamics) , geology , moment magnitude scale , geodesy , geometry , physics , chemistry , mathematics , organic chemistry , layer (electronics) , scaling , thermodynamics
The behavior of slip close to the trench during earthquakes is not well understood, and observations of large earthquakes breaking the near trench fault surface are rare. The 1995 M w 8.0 Jalisco earthquake seems to have broken the near‐trench area, as evidenced by large M s ‐M w disparity, small high‐frequency radiated energy compared to total energy, and low E r / M 0 ratios, in addition to several finite slip models showing large slip near the trench. However, slip models obtained using campaign Global Positioning System data suggest slip near shore. In this study we try to answer whether this event was a near‐trench event or not, by inverting teleseismic P , S , Rayleigh, and Love waves, as well as campaign Global Positioning System static offsets, either separately or jointly, to obtain the slip distribution on the fault as a function of time. We find two possible end‐member scenarios consistent with observed data: (1) coseismic slip distributed between coast and trench and no (or very little) postseismic slip and (2) coseismic slip principally near the trench with large (up to 1.8 m) aseismic slip occurring in the first 5–10 days after the earthquake, with a total moment corresponding to 16% of that of the event. We are unable to distinguish between these two end‐member scenarios by tsunami modeling and finally are neither able to conclude or exclude that the event was a typical near trench event.