Modeling Seismic Hazard By Integrating Historical Earthquake, Fault, and Strain Rate Data

Abstract eng:
The OpenQuake-engine software developed by the Global Earthquake Model (GEM) is an open-source tool for the calculation of seismic hazard and risk. It provides the capability to execute complex seismic hazard calculations on a range of scales, from detailed site-specific analysis to regional or global-scale models. However, users need to construct earthquake source models (ESMs), which characterize both the magnitude-frequency distribution of the earthquakes and their potential finite rupture geometries, and feed the ESMs to OpenQuake for hazard calculations. In this study, we propose a method to construct ESMs by integrating historical earthquake, geological fault, and strain rate data. The method requires division of the study area into large seismic zones, based on a set of defined seismotectonic criteria. For each zone, the seismicity rates are defined by a tapered Gutenberg-Richter (TGR) model. The TGR a- and bvalues are calculated using observed earthquake data, while the corner magnitude is constrained independently using the seismic moment rate inferred from a geodetically-based strain rate model. Then, we model the spatial distribution of the seismic activity based on characteristics of active faults, and location and magnitude patterns of historical earthquakes. The rates of large earthquakes accommodated on active faults are estimated based on the dimension, slip rate, and paleoseismic data of the faults. Remaining seismicity is distributed to the background using a smoothed seismicity model. Consistency between observed seismic activity rates and those predicted by the model should be verified in terms of both spatial and magnitude distributions. To achieve this, the OpenQuake-engine’s event-based seismic hazard tools are used to generate synthetic catalogs of tens or hundreds of thousands of years duration. We are developing a toolkit to implement this method. The toolkit is built upon the functionalities of GEM’s Hazard Modeller’s Toolkit. We use southwest China as an example to illustrate the method, workflow, and toolkit. We build the toolkit in a flexible manner so that users can make different modeling decisions at each step. This approach will help make the seismic hazard modeling process more transparent, and prompt the development of new methodologies for seismic hazard assessment.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket