High-resolution structures of the Landers fault zone inferred from aftershock waveform data Export

@article{li_etal:2007, abstract = {High-frequency body waves recorded by a temporary seismic array across the surface rupture trace of the 1992 Landers, California, earthquake were used to determine fault-zone structures down to the seismogenic depth. We first developed a technique to use generalized ray theory to compute synthetic seismograms for arbitrarily oriented tabular low-velocity fault-zone models. We then generated synthetic waveform record sections of a linear array across a vertical fault zone. They show that both arrival times and waveforms of P and S waves vary systematically across the fault due to transmissions and reflections from boundaries of the low-velocity fault zone. The waveform characteristics and arrival-time patterns in the record sections allow us to locate the boundaries of the fault zone and to determine its P- and S-wave velocities independently as well as its depth extent. Therefore, the trade-off between the fault-zone width and velocities can be avoided. Applying the method to the Landers waveform data reveals a low-velocity zone with a width of 270-360 m and a 35-60 per cent reduction in P and S velocities relative to the host rock. The analysis suggests that the low-velocity zone extends to a depth of \~{}7 km. The western boundary of the low-velocity zone coincides with the observed main surface rupture trace.}, address = {Department of Earth and Atmospheric Sciences, Saint Louis University, St Louis, MO 63108, USA. E-mail: lupei@eas.slu.edu}, author = {Li, Hongyi and Zhu, Lupei and Yang, Hongfeng}, citeulike-article-id = {1933649}, citeulike-linkout-0 = {http://dx.doi.org/10.1111/j.1365-246X.2007.03608.x}, citeulike-linkout-1 = {http://www.ingentaconnect.com/content/bsc/gji/2007/00000171/00000003/art00027}, citeulike-linkout-2 = {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2007GeoJI.171.1295L}, citeulike-linkout-3 = {http://www3.interscience.wiley.com/cgi-bin/abstract/118543481/ABSTRACT}, doi = {10.1111/j.1365-246X.2007.03608.x}, issn = {1365-246X}, journal = {Geophysical Journal International}, keywords = {faults, seismology}, month = {December}, number = {3}, pages = {1295--1307}, posted-at = {2009-06-15 08:45:23}, priority = {0}, publisher = {Blackwell Publishing}, title = {High-resolution structures of the {Landers} fault zone inferred from aftershock waveform data}, url = {http://dx.doi.org/10.1111/j.1365-246X.2007.03608.x}, volume = {171}, year = {2007} }

TY - JOUR ID - li_etal:2007 L3 - citeulike-article-id:1933649 N2 - High-frequency body waves recorded by a temporary seismic array across the surface rupture trace of the 1992 Landers, California, earthquake were used to determine fault-zone structures down to the seismogenic depth. We first developed a technique to use generalized ray theory to compute synthetic seismograms for arbitrarily oriented tabular low-velocity fault-zone models. We then generated synthetic waveform record sections of a linear array across a vertical fault zone. They show that both arrival times and waveforms of P and S waves vary systematically across the fault due to transmissions and reflections from boundaries of the low-velocity fault zone. The waveform characteristics and arrival-time patterns in the record sections allow us to locate the boundaries of the fault zone and to determine its P- and S-wave velocities independently as well as its depth extent. Therefore, the trade-off between the fault-zone width and velocities can be avoided. Applying the method to the Landers waveform data reveals a low-velocity zone with a width of 270-360 m and a 35-60 per cent reduction in P and S velocities relative to the host rock. The analysis suggests that the low-velocity zone extends to a depth of ~7 km. The western boundary of the low-velocity zone coincides with the observed main surface rupture trace. IS - 3 JF - Geophysical Journal International SN - 1365-246X AD - Department of Earth and Atmospheric Sciences, Saint Louis University, St Louis, MO 63108, USA. E-mail: lupei@eas.slu.edu EP - 1307 TI - High-resolution structures of the {Landers} fault zone inferred from aftershock waveform data PB - Blackwell Publishing VL - 171 SP - 1295 KW - faults KW - seismology AU - Li, Hongyi AU - Zhu, Lupei AU - Yang, Hongfeng PY - 2007/December// UR - http://dx.doi.org/10.1111/j.1365-246X.2007.03608.x ER -