← Back to Sessions

Two Global Ensemble Seismicity Models Obtained From the Combination of Interseismic Strain Rates and Earthquake-Catalog Data

Session: Constructing and Testing Regional and Global Earthquake Forecasts I

Type: Oral

Date: 4/20/2021

Presentation Time: 09:45 AM Pacific

Description: 

Global seismicity models provide scientific hypotheses about the rate, location and magnitude of earthquakes that will occur around the world. Given the aleatory variability of earthquake activity and epistemic uncertainties in seismicity forecasting, the veracity of these hypotheses can only be confirmed or rejected after prospective forecast evaluation. Here, we present the construction of and test results for two updated global earthquake models, aimed at providing mean estimates of shallow (d ≤ 70 km) seismicity for seismic hazard assessment. These approaches, referred to as the Tectonic Earthquake Activity Model (TEAM) and the World Hybrid Earthquake Estimates based on Likelihood scores (WHEEL) model, use a seismicity model for subduction zones that relies on geodetic strain rates, earthquake-catalog information and regional “geodesy-to-seismicity” parameters, such as fault-dipping angles, seismic coupling coefficients and estimates of corner magnitude. Thus, these ensemble models capture two independent components necessary for long-term earthquake forecasting, namely interseismic crustal strain accumulation and sudden lithospheric stress release. The calibration period for TEAM and WHEEL extends from January 1, 1977 to December 31, 2013. Accordingly, we use m≥ 5.95 earthquakes recorded during the 2014-2019 period to pseudo-prospectively evaluate the forecasting skills of these earthquake models, and statistically compare their performances to that of the Global Earthquake Activity Rate (GEAR1) model. Our pseudo-prospective test results show that GEAR1 and WHEEL are the most informative global seismicity models, as they overperform their individual model components during the six-year evaluation period. Nonetheless, further prospective evaluations are required to more accurately describe the abilities of these global ensemble seismicity models to forecast longer-term earthquake activity.

Presenting Author: Jose A. Bayona

Student Presenter: No

Authors