The global earthquake activity rate (GEAR1) seismicity model uses an optimized combination of geodetic strain rates, hypotheses about converting strain rates to seismicity rates from plate tectonics, and earthquake-catalog data to estimate global Mw = 5:767 shallow (= 70 km) seismicity rates. It comprises two parent models: a strain rate-based model and a smoothedseismicity based model. The GEAR1 model was retrospectively evaluated and calibrated using earthquake data from 2005 to 2012, resulting in a preferred log-linear multiplicative combination of the parent forecasts. Since 1 October 2015, the GEAR1 model has undergone prospective evaluation within the Collaboratory for the Study of Earthquake Predictability (CSEP) testing center, forecasting Mw = 5:95 seismicity. We present initial prospective forecast test results for the GEAR1 model, its tectonic and seismicity components, and for the first iteration of the strain-rate-based model, during the 1 October 2015-7 September 2017 period. During the evaluation period, observed earthquakes are consistent with the GEAR1 forecast and comparative test results likewise support that GEAR1 is more informative than either of its components alone. Based on a combination of retrospective and prospective testing, the tectonic forecasts do not effectively anticipate observed spatial earthquake distribution, largely due to overlocalization of the model with respect to observed earthquake distributions.
|Original language||English (US)|
|Number of pages||10|
|Journal||Seismological Research Letters|
|State||Published - Jun 13 2018|
Bibliographical noteKAUST Repository Item: Exported on 2022-06-03
Acknowledged KAUST grant number(s): URF/1/2160-01-01
Acknowledgements: The authors thank Peter Bird, David D. Jackson, Corne Kreemer, Yan Kagan, and Ross Stein for the development of the global earthquake activity rate (GEAR1) model and its components, as well as valuable discussion on interpreting prospective forecast test results. Additionally, Peter Bird developed and provided code to generate the GEAR1 forecast, which he adapted to generate the Kagan-Jackson smoothed seismicity (KJSS) smoothed seismicity forecast. The authors thank Guest Editor Andy Michael and reviewers Domenico Giardini and Matteo Taroni for their insightful comments and suggestions regarding what information could be inferred from the prospective testing results. The authors also thank Thomas Beutin and John Yu for technical support with running the Collaboratory for the Study of Earthquake Predictability (CSEP) tests. This study was made possible by the open-source community and the Linux operating system. This research was funded by the Global Earthquake Model (GEM) foundation and King Abdullah University of Science and Technology (KAUST) research Grant URF/1/2160-01-01.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.