scholarly journals Prospective Evaluation of Global Earthquake Forecast Models: 2 Yrs of Observations Provide Preliminary Support for Merging Smoothed Seismicity with Geodetic Strain Rates

2018 ◽  
Vol 89 (4) ◽  
pp. 1262-1271 ◽  
Author(s):  
Anne Strader ◽  
Maximilian Werner ◽  
José Bayona ◽  
Philip Maechling ◽  
Fabio Silva ◽  
...  
Keyword(s):  
Strain Rates ◽  
Prospective Evaluation ◽  
Earthquake Forecast ◽  
Smoothed Seismicity ◽  
Forecast Models ◽  
Geodetic Strain ◽  
Preliminary Support

Prospective Evaluation of Multiplicative Hybrid Earthquake Forecast Models for California

2021 ◽  
Author(s):  
Jose A. Bayona ◽  
William Savran ◽  
Maximilian Werner ◽  
David A. Rhoades
Keyword(s):  
Information Gain ◽  
Earthquake Swarm ◽  
Hybrid Models ◽  
Test Results ◽  
Prospective Evaluation ◽  
Earthquake Forecast ◽  
Significant Information ◽  
Likelihood Functions ◽  
Earthquake Predictability ◽  
Forecast Models

<p>Developing testable seismicity models is essential for robust seismic hazard assessments and to quantify the predictive skills of posited hypotheses about seismogenesis. On this premise, the Regional Earthquake Likelihood Models (RELM) group designed a joint forecasting experiment, with associated models, data and tests to evaluate earthquake predictability in California over a five-year period. Participating RELM forecast models were based on a range of geophysical datasets, including earthquake catalogs, interseismic strain rates, and geologic fault slip rates. After five years of prospective evaluation, the RELM experiment found that the smoothed seismicity (HKJ) model by Helmstetter et al. (2007) was the most informative. The diversity of competing forecast hypotheses in RELM was suitable for combining multiple models that could provide more informative earthquake forecasts than HKJ. Thus, Rhoades et al. (2014) created multiplicative hybrid models that involve the HKJ model as a baseline and one or more conjugate models. Particularly, the authors fitted two parameters for each conjugate model and an overall normalizing constant to optimize each hybrid model. Then, information gain scores per earthquake were computed using a corrected Akaike Information Criterion that penalized for the number of fitted parameters. According to retrospective analyses, some hybrid models showed significant information gains over the HKJ forecast, despite the penalty. Here, we assess in a prospective setting the predictive skills of 16 hybrids and 6 original RELM forecasts, using a suite of tests of the Collaboratory for the Study of Earthquake Predicitability (CSEP). The evaluation dataset contains 40 M≥4.95 events recorded within the California CSEP-testing region from 1 January 2011 to 31 December 2020, including the 2016 Mw 5.6, 5.6, and 5.5 Hawthorne earthquake swarm, and the Mw 6.4 foreshock and Mw 7.1 mainshock from the 2019 Ridgecrest sequence. We evaluate the consistency between the observed and the expected number, spatial, likelihood and magnitude distributions of earthquakes, and compare the performance of each forecast to that of HKJ. Our prospective test results show that none of the hybrid models are significantly more informative than the HKJ baseline forecast. These results are mainly due to the occurrence of the 2016 Hawthorne earthquake cluster, and four events from the 2019 Ridgecrest sequence in two forecast bins. These clusters of seismicity are exceptionally unlikely in all models, and insufficiently captured by the Poisson distribution that the likelihood functions of tests assume. Therefore, we are currently examining alternative likelihood functions that reduce the sensitivity of the evaluations to clustering, and that could be used to better understand whether the discrepancies between prospective and retrospective test results for multiplicative hybrid forecasts are due to limitations of the tests or the methods used to create the hybrid models. </p>

GEAR1: A Global Earthquake Activity Rate Model Constructed from Geodetic Strain Rates and Smoothed Seismicity

2015 ◽  
Vol 105 (5) ◽  
pp. 2538-2554 ◽  
Author(s):  
P. Bird ◽  
D. D. Jackson ◽  
Y. Y. Kagan ◽  
C. Kreemer ◽  
R. S. Stein
Keyword(s):  
Earthquake Activity ◽  
Strain Rates ◽  
Rate Model ◽  
Activity Rate ◽  
Smoothed Seismicity ◽  
Geodetic Strain

A Regionalized Seismicity Model for Subduction Zones Based on Geodetic Strain Rates, Geomechanical Parameters, and Earthquake‐Catalog Data

2019 ◽  
Vol 109 (5) ◽  
pp. 2036-2049 ◽  
Author(s):  
José Antonio Bayona Viveros ◽  
Sebastian von Specht ◽  
Anne Strader ◽  
Sebastian Hainzl ◽  
Fabrice Cotton ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Seismic Moment ◽  
Subduction Zones ◽  
Earthquake Activity ◽  
Earthquake Catalog ◽  
Strain Rates ◽  
Earthquake Forecast ◽  
Earthquake Parameters ◽  
Seismicity Rates ◽  
Geodetic Strain

Abstract The Seismic Hazard Inferred from Tectonics based on the Global Strain Rate Map (SHIFT_GSRM) earthquake forecast was designed to provide high‐resolution estimates of global shallow seismicity to be used in seismic hazard assessment. This model combines geodetic strain rates with global earthquake parameters to characterize long‐term rates of seismic moment and earthquake activity. Although SHIFT_GSRM properly computes seismicity rates in seismically active continental regions, it underestimates earthquake rates in subduction zones by an average factor of approximately 3. We present a complementary method to SHIFT_GSRM to more accurately forecast earthquake rates in 37 subduction segments, based on the conservation of moment principle and the use of regional interface seismicity parameters, such as subduction dip angles, corner magnitudes, and coupled seismogenic thicknesses. In seven progressive steps, we find that SHIFT_GSRM earthquake‐rate underpredictions are mainly due to the utilization of a global probability function of seismic moment release that poorly captures the great variability among subduction megathrust interfaces. Retrospective test results show that the forecast is consistent with the observations during the 1 January 1977 to 31 December 2014 period. Moreover, successful pseudoprospective evaluations for the 1 January 2015 to 31 December 2018 period demonstrate the power of the regionalized earthquake model to properly estimate subduction‐zone seismicity.

scholarly journals Static stress drop as determined from geodetic strain rates and statistical seismicity

2011 ◽  
Vol 116 (B2) ◽  
Author(s):  
Alessandro Caporali ◽  
Salvatore Barba ◽  
Michele M. C. Carafa ◽  
Roberto Devoti ◽  
Grazia Pietrantonio ◽  
...  
Keyword(s):  
Stress Drop ◽  
Static Stress ◽  
Strain Rates ◽  
Static Stress Drop ◽  
Geodetic Strain

scholarly journals Prospective and retrospective evaluation of five-year earthquake forecast models for California

2017 ◽  
Vol 211 (1) ◽  
pp. 239-251 ◽  
Author(s):  
Anne Strader ◽  
Max Schneider ◽  
Danijel Schorlemmer
Keyword(s):  
Retrospective Evaluation ◽  
Earthquake Forecast ◽  
Forecast Models

scholarly journals Comparison of seismic and geodetic strain rates at the margins of the Ordos Plateau, northern China

2017 ◽  
Vol 212 (2) ◽  
pp. 988-1009 ◽  
Author(s):  
Timothy A Middleton ◽  
Barry Parsons ◽  
Richard T Walker
Keyword(s):  
Northern China ◽  
Strain Rates ◽  
Ordos Plateau ◽  
Geodetic Strain
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