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Title of article :
Co-seismic strike–slip fault displacement determined from push-up structures: the Selsund Fault case, South Iceland
Author/Authors :
Angelier، نويسنده , , Jacques and Bergerat، نويسنده , , Françoise and Bellou، نويسنده , , Magalie and Homberg، نويسنده , , Catherine، نويسنده ,
Issue Information :
ماهنامه با شماره پیاپی سال 2004
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Abstract :
We analysed push-up structures along the Selsund Fault, a N–S right-lateral strike-slip fault activated during the 1912 earthquake in the South Iceland Seismic Zone. Volume changes and syn-tectonic collapse affected push-ups during the earthquake, followed by post-seismic gravitational sagging. To determine the push-up shortening, and hence the strike–slip fault motion, we define a virtual push-up structure, without volume change and collapse, and we compare it with the present-day configuration. Whereas length comparisons are subject to errors, volumetric analysis allows determination of shortening through evaluation of the thickness of the deformed layer affected by the push-ups. We determine a co-seismic peak displacement of 2.4 m along the rupture trace. This value is consistent with the magnitude 7 of the earthquake, based on empirical relationships. Neglecting volume changes and collapse effects gives underestimated displacement. The new method for analysing push-up structures thus allows better determination of magnitudes of ancient earthquakes along strike–slip faults.
Keywords :
Strike–slip , Push-up structure , magnitude , Seismotectonics , earthquake , Iceland , Rupture trace
Journal title :
Journal of Structural Geology
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