The Southern California Network Bulletin: 1990-1993 Summary

Wald, Lisa A.; Hutton, Laura; Given, Douglas D.

doi:10.1785/gssrl.66.1.9

Cited by 23 publications

(23 citation statements)

References 18 publications

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“…The SCSN uses a velocity model similar to Hadley and Kanamori [1977] for Southern California [e.g., Wald et al, 1995;Shearer, 1997;Wald and Scharwz, 2000;Shearer et al, 2005;Hauksson and Shearer, 2005;Hutton et al, 2006]. The mean horizontal and vertical location errors and root mean square (RMS) traveltime residuals of the events reported in the SCSN catalog are 1.89 km, 2.59 km, and 0.36 s, respectively.…”

Section: Relocation Proceduresmentioning

confidence: 99%

“…Several studies show increased aftershock activity adjacent to areas of high slip and high moment release [e.g., Wald et al, 1995;Thio and Kanamori, 1996;Ma and Chan, 2005]. Others show higher aftershock rates in areas with increased shear and Coulomb stress near the ends of a fault rupture [e.g., Mendoza and Hartzell, 1988;Toda et al, 2005].…”

Section: Spatiotemporal Aftershock Behaviormentioning

confidence: 99%

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Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

et al. 2013

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[1] We detect and precisely locate over 9500 aftershocks that occurred in the Yuha Desert region during a 2 month period following the 4 April 2010 M w 7.2 El Mayor-Cucapah (EMC) earthquake. Events are relocated using a series of absolute and relative relocation procedures that include Hypoinverse, Velest, and hypoDD. Location errors are reduced to 40 m horizontally and 120 m vertically. Aftershock locations reveal a complex pattern of faulting with en echelon fault segments trending toward the northwest, approximately parallel to the North American-Pacific plate boundary and en echelon, conjugate features trending to the northeast. The relocated seismicity is highly correlated with published surface mapping of faults that experienced triggered surface slip in response to the EMC main shock. Aftershocks occurred between 2 km and 11 km depths, consistent with previous studies of seismogenic thickness in the region. Three-dimensional analysis reveals individual and intersecting fault planes that are limited in their along-strike length. These fault planes remain distinct structures at depth, indicative of conjugate faulting, and do not appear to coalesce onto a throughgoing fault segment. We observe a complex spatiotemporal migration of aftershocks, with seismicity that jumps between individual fault segments that are active for only a few days to weeks. Aftershock rates are roughly consistent with the expected earthquake production rates of Dieterich (1994). The conjugate pattern of faulting and nonuniform aftershock migration patterns suggest that strain in the Yuha Desert is being accommodated in a complex manner.

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Section: Relocation Proceduresmentioning

confidence: 99%

Section: Spatiotemporal Aftershock Behaviormentioning

confidence: 99%

Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

et al. 2013

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“…The wide‐angle nature of the experiment precludes information on the upper crust, so we assume a velocity of 5.5 km/s, consistent with the upper crust of the average southern California velocity model [ Wald et al , 1995]. Near‐surface velocity anomalies in the paths of the receivers will be mapped into the station delays.…”

Section: Resultsmentioning

confidence: 99%

“…We demonstrate this with a synthetic example. The synthetic travel times from an average southern California crust model [ Wald et al , 1995] have been convolved with a representative waveform to simulate the multiple reverberations found in the actual data (Figure 3a). The resulting envelope of the Radon transform is shown in Figure 3b.…”

Section: Techniquementioning

confidence: 99%

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Crustal structure of the Borderland‐Continent Transition Zone of southern California adjacent to Los Angeles

Nazareth¹

2003

J. Geophys. Res.

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We use data from the onshore‐offshore component of Los Angeles Region Seismic Experiment (LARSE) to model the broad‐scale features of the midcrust to upper mantle beneath a north‐south transect that spans the continental borderland in the Los Angeles, California, region. We have developed an analysis method for wide‐angle seismic data that consists primarily of refractions, lacks near‐offset recordings, and contains wide gaps in coverage. Although the data restrict the analysis to the modeling of broad‐scale structure, the technique allows one to explore the limits of the data and determine the resolving power of the data set. The resulting composite velocity model constrains the crustal thickness and location and width of the continent‐Borderland transition zone. We find that the mid to lower crust layer velocities of the Inner Borderland are slightly lower than the corresponding layers in the average southern California crust model, while the upper mantle velocity is significantly higher. The data require the Moho to deepen significantly to the north. We constrain the transition zone to initiate between the offshore slope and the southwest Los Angeles Basin. If the Inner Borderland crust is 22 km thick, then the transition zone is constrained to initiate within a 2 km wide region beneath the southwest Los Angeles Basin, and have a width of 20–25 km. The strong, coherent, and continuous Pn phase suggests the Moho is coherent and laterally continuous beneath the Inner Borderland and transition zone. The Inner California Borderland seems to be modified and thickened oceanic crust, with the oceanic upper mantle intact beneath it.

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Self‐contained local broadband seismogeodetic early warning system: Detection and location

Goldberg

Bock

2017

JGR Solid Earth

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Earthquake and local tsunami early warning is critical to mitigating adverse impacts of large‐magnitude earthquakes. An optimal system must rely on near‐source data to maximize warning time. To this end, we have developed a self‐contained seismogeodetic early warning system employing an optimal combination of high‐frequency information from strong‐motion accelerometers and low‐frequency information from collocated Global Navigation Satellite Systems (GNSS) instruments to estimate real‐time displacements and velocities. Like GNSS, and unlike broadband seismometers, seismogeodetic stations record the full waveform, including static offset, without clipping in the near‐field or saturating for large magnitude earthquakes. However, GNSS alone cannot provide a self‐contained system and requires an external seismic trigger. Seismogeodetic stations detect P wave arrivals with the same sensitivity as strong‐motion accelerometers and thus provide a stand‐alone system. We demonstrate the utility of near‐source seismogeodesy for event detection and location with analysis of the 2010 Mw7.2 El Mayor‐Cucapah, Baja, California and 2014 Mw6.0 Napa, California strike‐slip events, and the 2014 Mw8.2 Iquique, Chile subduction zone earthquake using observatory‐grade accelerometers and GPS data. We present lessons from the 2014 Mw4.0 Piedmont, California and 2016 Mw5.2 Borrego Springs, California earthquakes, recorded by our seismogeodetic system with Micro‐Electro Mechanical System (MEMS) accelerometers and GPS data and reanalyzed retrospectively. We conclude that our self‐contained seismogeodetic system is suitable for early warning for earthquakes of significance (>M5) using either observatory‐grade or MEMS accelerometers. Finally, we discuss the effect of network design on hypocenter location and suggest the deployment of additional seismogeodetic stations for the western U.S.

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The Southern California Network Bulletin: 1990-1993 Summary

Cited by 23 publications

References 18 publications

Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

Crustal structure of the Borderland‐Continent Transition Zone of southern California adjacent to Los Angeles

Self‐contained local broadband seismogeodetic early warning system: Detection and location

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The Southern California Network Bulletin: 1990-1993 Summary

Cited by 23 publications

References 18 publications

Aftershocks of the 2010 Mw 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

Aftershocks of the 2010 Mw 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

Crustal structure of the Borderland‐Continent Transition Zone of southern California adjacent to Los Angeles

Self‐contained local broadband seismogeodetic early warning system: Detection and location

Contact Info

Product

Resources

About

Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California

Aftershocks of the 2010 M_w 7.2 El Mayor‐Cucapah earthquake reveal complex faulting in the Yuha Desert, California