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Mapping 3D fault geometry in earthquakes using high‐resolution topography: Examples from the 2010 El Mayor‐Cucapah (Mexico) and 2013 Balochistan (Pakistan) earthquakes
Author(s) -
Zhou Yu,
Walker Richard T.,
Elliott John R.,
Parsons Barry
Publication year - 2016
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 - 10.1002/2016gl067899
Subject(s) - geology , fault trace , seismology , geodetic datum , fault (geology) , outcrop , structural geology , extension (predicate logic) , high resolution , geodesy , remote sensing , geomorphology , computer science , programming language
Fault dips are usually measured from outcrops in the field or inferred through geodetic or seismological modeling. Here we apply the classic structural geology approach of calculating dip from a fault's 3‐D surface trace using recent, high‐resolution topography. A test study applied to the 2010 El Mayor‐Cucapah earthquake shows very good agreement between our results and those previously determined from field measurements. To obtain a reliable estimate, a fault segment ≥120 m long with a topographic variation ≥15 m is suggested. We then applied this method to the 2013 Balochistan earthquake, getting dips similar to previous estimates. Our dip estimates show a switch from north to south dipping at the southern end of the main trace, which appears to be a response to local extension within a stepover. We suggest that this previously unidentified geometrical complexity may act as the endpoint of earthquake ruptures for the southern end of the Hoshab fault.