Title: Assessing the role of stress transfer on aftershock locations
Abstract: The influence of the static stress changes caused by the M w 6.5 Kozani‐Grevena (Greece) earthquake of 13 May 1995 on aftershock locations is investigated. A three‐fault rupture model for the main shock, aftershock relocations, and fault plane solutions for the aftershocks is available. We have developed a testing method, which tests whether the proportions of aftershocks located inside areas determined by a selected criterion on the static stress change could be attained if there were no effect of the stress change due to the main shock on aftershock locations. The areas of stress change are determined at the focus of every aftershock. The analysis is performed separately for areas defined by a positive stress change greater than or equal to 0.1, 0.3, 1.0, 5.0, and 10.0 bar and by a negative change less than or equal to −0.1, −0.3, −1.0, −5.0, and −10.0 bar. The tests have confidently indicated a rise in probability to locate aftershocks inside areas of positive static stress change, which supports the hypothesis on the triggering effect in these areas. The analysis has not evidenced the existence of stress shadows inside areas of larger negative stress change. On the contrary, the tests have indicated a significant increase of the probability of event location in the areas of a change less than or equal to −5.0 and −10.0 bar. For areas of larger absolute stress change this probability increases regardless of the sign of the change though distinctly more in areas of positive than of negative change.
Publication Year: 2009
Publication Date: 2009-11-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 15
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