%0 Journal Article %1 allmann_shearer:2007 %A Allmann, Bettina P. %A Shearer, Peter M. %D 2007 %J Science %K geophysics seismology %N 5854 %P 1279--1283 %R 10.1126/science.1146537 %T A high-frequency secondary event during the 2004 Parkfield earthquake %U http://dx.doi.org/10.1126/science.1146537 %V 318 %X By using seismic records of the 2004 magnitude 6.0 Parkfield earthquake, we identified a burst of high-frequency seismic radiation that occurred about 13 kilometers northwest of the hypocenter and 5 seconds after rupture initiation. We imaged this event in three dimensions by using a waveform back-projection method, as well as by timing distinct arrivals visible on many of the seismograms. The high-frequency event is located near the south edge of a large slip patch seen in most seismic and geodetic inversions, indicating that slip may have grown abruptly at this point. The time history obtained from full-waveform back projection suggests a rupture velocity of 2.5 kilometers per second. Energy estimates for the subevent, together with long-period slip inversions, indicate a lower average stress drop for the northern part of the Parkfield earthquake compared with that for the region near its hypocenter, which is in agreement with stress-drop estimates obtained from small-magnitude aftershocks. 10.1126/science.1146537

@article{allmann_shearer:2007, abstract = {By using seismic records of the 2004 magnitude 6.0 Parkfield earthquake, we identified a burst of high-frequency seismic radiation that occurred about 13 kilometers northwest of the hypocenter and 5 seconds after rupture initiation. We imaged this event in three dimensions by using a waveform back-projection method, as well as by timing distinct arrivals visible on many of the seismograms. The high-frequency event is located near the south edge of a large slip patch seen in most seismic and geodetic inversions, indicating that slip may have grown abruptly at this point. The time history obtained from full-waveform back projection suggests a rupture velocity of 2.5 kilometers per second. Energy estimates for the subevent, together with long-period slip inversions, indicate a lower average stress drop for the northern part of the Parkfield earthquake compared with that for the region near its hypocenter, which is in agreement with stress-drop estimates obtained from small-magnitude aftershocks. 10.1126/science.1146537}, added-at = {2012-09-01T13:08:21.000+0200}, author = {Allmann, Bettina P. and Shearer, Peter M.}, biburl = {https://www.bibsonomy.org/bibtex/2de61304733d73f911656d1ea29a58f30/nilsma}, day = 23, doi = {10.1126/science.1146537}, interhash = {8e189171bc09a8c4a5d432b192246040}, intrahash = {de61304733d73f911656d1ea29a58f30}, issn = {0036-8075}, journal = {Science}, keywords = {geophysics seismology}, month = nov, number = 5854, pages = {1279--1283}, pmid = {18033878}, timestamp = {2021-02-09T13:25:06.000+0100}, title = {A high-frequency secondary event during the 2004 Parkfield earthquake}, url = {http://dx.doi.org/10.1126/science.1146537}, volume = 318, year = 2007 }