Strong shaking in Los Angeles expected from southern San Andreas earthquake

Olsen, Kim B.; Day, Steven M.; Minster, J. B.; Cui, Yifeng; Chourasia, Amit; Faerman, M.; Moore, Reagan; Maechling, P. J.; Jordan, Thomas H.

doi:10.1029/2005gl025472

Cited by 190 publications

(134 citation statements)

References 16 publications

(18 reference statements)

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“…Nevertheless, this reflects the potential long geographical reach of hazard influences, which are not reflected in the evaluation metrics presented above. For example, it has been shown that earthquakes on the San Andreas (Coachella) rev can efficiently channel long-period ground motions into the greater LA basin (e.g., Olsen et al, 2006), so a hazard map for such shaking might show consequential gains in this highly populated area. This also exemplifies how conclusions will depend on the exact hazard metric.…”

Section: Hazard Map Ratiosmentioning

confidence: 99%

Long‐Term Time‐Dependent Probabilities for the Third Uniform California Earthquake Rupture Forecast (UCERF3)

Field

Biasi

Bird

et al. 2015

Bulletin of the Seismological Society of America

198

129

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The 2014 Working Group on California Earthquake Probabilities (WGCEP 2014) presents time-dependent earthquake probabilities for the third Uniform California Earthquake Rupture Forecast (UCERF3). Building on the UCERF3 time-independent model published previously, renewal models are utilized to represent elasticrebound-implied probabilities. A new methodology has been developed that solves applicability issues in the previous approach for unsegmented models. The new methodology also supports magnitude-dependent aperiodicity and accounts for the historic open interval on faults that lack a date-of-last-event constraint. Epistemic uncertainties are represented with a logic tree, producing 5760 different forecasts. Results for a variety of evaluation metrics are presented, including logic-tree sensitivity analyses and comparisons to the previous model (UCERF2). For 30 yr M ≥ 6:7 probabilities, the most significant changes from UCERF2 are a threefold increase on the Calaveras fault and a threefold decrease on the San Jacinto fault. Such changes are due mostly to differences in the time-independent models (e.g., fault-slip rates), with relaxation of segmentation and inclusion of multifault ruptures being particularly influential. In fact, some UCERF2 faults were simply too long to produce M 6.7 size events given the segmentation assumptions in that study. Probability model differences are also influential, with the implied gains (relative to a Poisson model) being generally higher in UCERF3. Accounting for the historic open interval is one reason. Another is an effective 27% increase in the total elastic-rebound-model weight. The exact factors influencing differences between UCERF2 and UCERF3, as well as the relative importance of logic-tree branches, vary throughout the region and depend on the evaluation metric of interest. For example, M ≥ 6:7 probabilities may not be a good proxy for other hazard or loss measures. This sensitivity, coupled with the approximate nature of the model and known limitations, means the applicability of UCERF3 should be evaluated on a case-by-case basis.

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Section: Hazard Map Ratiosmentioning

confidence: 99%

Long‐Term Time‐Dependent Probabilities for the Third Uniform California Earthquake Rupture Forecast (UCERF3)

Field

Biasi

Bird

et al. 2015

Bulletin of the Seismological Society of America

198

129

View full text Add to dashboard Cite

show abstract

“…In particular, areas characterized by low wavespeed sedimentary basins may show a very different ground response compared to hardrock sites, with strong amplifications, multiple reverberations, and prolonged shaking (e.g., Rovelli et al, 2001;Olsen et al, 2006;Chaljub et al, 2007;Lee et al, 2008). Moreover, these effects can be intensified and complicated by topographic ridges, which can cause amplifications, reflections, and multipathing (e.g., Lee et al, 2008;).…”

Section: Simulations With a 3d Model: Effects Of Geological Structuresmentioning

confidence: 99%

Spectral-Element Simulations of Seismic Waves Generated by the 2009 L'Aquila Earthquake

Magnoni¹,

Casarotti²,

Michelini³

et al. 2013

Bulletin of the Seismological Society of America

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We adopt a spectral-element method (SEM) to perform numerical simulations of the complex wavefield generated by the 6 April 2009 M w 6.3 L'Aquila earthquake in central Italy. The mainshock is represented by a finite-fault solution obtained by inverting strong-motion and Global Positioning System data, testing both 1D and 3D wavespeed models for central Italy. Surface topography, attenuation, and the Moho discontinuity are also accommodated. Including these complexities is essential to accurately simulate seismic-wave propagation. Three-component synthetic waveforms are compared to corresponding velocimeter and strong-motion recordings. The results show a favorable match between data and synthetics up to ∼0:5 Hz in a 200 km × 200 km × 60 km model volume, capturing features mainly related to topography or low-wavespeed basins. We construct synthetic peak ground velocity maps that, for the 3D model, are in good agreement with observations, thus providing valuable information for seismic-hazard assessment. Exploiting the SEM in combination with an adjoint method, we calculate finite-frequency kernels for specific seismic arrivals. These kernels capture the volumetric sensitivity associated with the selected waveform and highlight prominent effects of topography on seismic-wave propagation in central Italy.

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“…One approach for improving hazard estimates is to simulate the wave propagation through realistic 3D crustal models (Olsen et al, 1995(Olsen et al, , 2006Komatitsch et al, 2004;Graves et al, 2008). If seismograms can be simulated for sufficiently large samples of probable ruptures, then hazard curves of exceedance probability versus seismic intensity can be constructed from the calculated site response.…”

Section: Introductionmentioning

confidence: 99%

Testing Waveform Predictions of 3D Velocity Models against Two Recent Los Angeles Earthquakes

Lee

Chen

Jordan

2014

Seismological Research Letters

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Strong shaking in Los Angeles expected from southern San Andreas earthquake

Cited by 190 publications

References 16 publications

Long‐Term Time‐Dependent Probabilities for the Third Uniform California Earthquake Rupture Forecast (UCERF3)

Long‐Term Time‐Dependent Probabilities for the Third Uniform California Earthquake Rupture Forecast (UCERF3)

Spectral-Element Simulations of Seismic Waves Generated by the 2009 L'Aquila Earthquake

Testing Waveform Predictions of 3D Velocity Models against Two Recent Los Angeles Earthquakes

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