eprintid: 1380 rev_number: 12 eprint_status: archive userid: 2 dir: disk0/00/00/13/80 datestamp: 2015-02-25 09:08:58 lastmod: 2017-02-08 12:21:40 status_changed: 2015-04-27 12:10:48 type: article metadata_visibility: show creators_name: Pollitz, Fred F. creators_name: Johnston, Malcolm J. S. corp_creators: U.S. Geological Survey, Menlo Park, California, USA corp_creators: U.S. Geological Survey, Menlo Park, California, USA title: Direct test of static stress versus dynamic stress triggering of aftershocks ispublished: pub subjects: SS divisions: EPOS-P full_text_status: none abstract: Aftershocks observed over time scales of minutes to months following a main shock are plausibly triggered by the static stress change imparted by the main shock, dynamic shaking effects associated with passage of seismic waves from the main shock, or a combination of the two. We design a direct test of static versus dynamic triggering of aftershocks by comparing the near-field temporal aftershock patterns generated by aseismic and impulsive events occurring in the same source area. The San Juan Bautista, California, area is ideally suited for this purpose because several events of both types of M ∼ 5 have occurred since 1974. We find that aftershock rates observed after impulsive events are much higher than those observed after aseismic events, and this pattern persists for several weeks after the event. This suggests that, at least in the near field, dynamic triggering is the dominant cause of aftershocks, and that it generates both immediate and delayed aftershock activity. date: 2006-08-11 date_type: published publication: Geophysical Research Letters volume: 33 number: 15 publisher: American Geophysical Union pagerange: 1-5 id_number: doi:10.1029/2006GL026764 refereed: TRUE issn: 0094-8276 official_url: http://dx.doi.org/10.1029/2006GL026764 access_IS-EPOS: limited owner: Publisher citation: Pollitz, Fred F. and Johnston, Malcolm J. S. (2006) Direct test of static stress versus dynamic stress triggering of aftershocks. Geophysical Research Letters, 33 (15). pp. 1-5. DOI: https://doi.org/10.1029/2006GL026764 <https://doi.org/10.1029/2006GL026764>