Highly damaged rocks within the San Andreas fault zone at Parkfield
form a low-velocity waveguide for seismic waves, giving rise to fault-guided
waves. Prominent fault-guided waves have been observed at the San
Andreas Fault Observatory at Depth (SAFOD) site, including a surface
array across the fault zone and a borehole seismograph placed in
the SAFOD well at a depth of \~2.7 km below ground. The resulting
observations are modeled here using 3-D finite-difference methods.
To fit the amplitude, frequency, and travel-time characteristics
of the data, the models require a downward tapering, 30-40-m wide
fault-core embedded in a 100-200-m wide jacket. Compared with the
intact wall rocks, the core velocities are reduced by \~40\% and
jacket velocities by \~25\%. Based on the depths of earthquakes
generating guided waves, we estimate that the low-velocity waveguide
along the fault at SAFOD extends at least to depths of \~7 km,
more than twice the depth reported in pervious studies.
%0 Journal Article
%1 li_malin:2008
%A Li, Yong-Gang
%A Malin, Peter E.
%D 2008
%J Geophysical Research Letters
%K geophysics seismology
%N 8
%P L08304+
%R 10.1029/2007GL032924
%T San Andreas Fault damage at SAFOD viewed with fault-guided waves
%U http://dx.doi.org/10.1029/2007GL032924
%V 35
%X Highly damaged rocks within the San Andreas fault zone at Parkfield
form a low-velocity waveguide for seismic waves, giving rise to fault-guided
waves. Prominent fault-guided waves have been observed at the San
Andreas Fault Observatory at Depth (SAFOD) site, including a surface
array across the fault zone and a borehole seismograph placed in
the SAFOD well at a depth of \~2.7 km below ground. The resulting
observations are modeled here using 3-D finite-difference methods.
To fit the amplitude, frequency, and travel-time characteristics
of the data, the models require a downward tapering, 30-40-m wide
fault-core embedded in a 100-200-m wide jacket. Compared with the
intact wall rocks, the core velocities are reduced by \~40\% and
jacket velocities by \~25\%. Based on the depths of earthquakes
generating guided waves, we estimate that the low-velocity waveguide
along the fault at SAFOD extends at least to depths of \~7 km,
more than twice the depth reported in pervious studies.
@article{li_malin:2008,
abstract = {Highly damaged rocks within the San Andreas fault zone at Parkfield
form a low-velocity waveguide for seismic waves, giving rise to fault-guided
waves. Prominent fault-guided waves have been observed at the San
Andreas Fault Observatory at Depth (SAFOD) site, including a surface
array across the fault zone and a borehole seismograph placed in
the SAFOD well at a depth of \~{}2.7 km below ground. The resulting
observations are modeled here using 3-D finite-difference methods.
To fit the amplitude, frequency, and travel-time characteristics
of the data, the models require a downward tapering, 30-40-m wide
fault-core embedded in a 100-200-m wide jacket. Compared with the
intact wall rocks, the core velocities are reduced by \~{}40\% and
jacket velocities by \~{}25\%. Based on the depths of earthquakes
generating guided waves, we estimate that the low-velocity waveguide
along the fault at SAFOD extends at least to depths of \~{}7 km,
more than twice the depth reported in pervious studies.},
added-at = {2012-09-01T13:08:21.000+0200},
author = {Li, Yong-Gang and Malin, Peter E.},
biburl = {https://www.bibsonomy.org/bibtex/28d2efe1ead71ac1f2fe94f51b58c6945/nilsma},
day = 19,
doi = {10.1029/2007GL032924},
interhash = {5e2beb2751feab5d617c91ca201f0fed},
intrahash = {8d2efe1ead71ac1f2fe94f51b58c6945},
issn = {0094-8276},
journal = {Geophysical Research Letters},
keywords = {geophysics seismology},
month = apr,
number = 8,
pages = {L08304+},
timestamp = {2021-02-09T13:22:13.000+0100},
title = {San Andreas Fault damage at SAFOD viewed with fault-guided waves},
url = {http://dx.doi.org/10.1029/2007GL032924},
volume = 35,
year = 2008
}