Premium
Comparison of coseismic near‐field and off‐fault surface deformation patterns of the 1992 M w 7.3 Landers and 1999 M w 7.1 Hector Mine earthquakes: Implications for controls on the distribution of surface strain
Author(s) -
Milliner C. W. D.,
Dolan J. F.,
Hollingsworth J.,
Leprince S.,
Ayoub F.
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 - 10.1002/2016gl069841
Subject(s) - geology , seismology , fault (geology) , deformation (meteorology) , lithology , geodetic datum , subpixel rendering , shear (geology) , geodesy , petrology , oceanography , pixel , computer science , computer vision
Subpixel correlation of preevent and postevent air photos reveal the complete near‐field, horizontal surface deformation patterns of the 1992 M w 7.3 Landers and 1999 M w 7.1 Hector Mine ruptures. Total surface displacement values for both earthquakes are systematically larger than “on‐fault” displacements from geologic field surveys, indicating significant distributed, inelastic deformation occurred along these ruptures. Comparison of these two data sets shows that 46 ± 10% and 39 ± 22% of the total surface deformation were distributed over fault zones averaging 154 m and 121 m in width for the Landers and Hector Mine events, respectively. Spatial variations of distributed deformation along both ruptures show correlations with the type of near‐surface lithology and degree of fault complexity; larger amounts of distributed shear occur where the rupture propagated through loose unconsolidated sediments and areas of more complex fault structure. These results have basic implications for geologic‐geodetic rate comparisons and probabilistic seismic hazard analysis.