Models Developed by GEM: Methods for Construction

The GEM Global Seismic Hazard Mosaic includes models that were developed by the GEM secretariat, in addition to the models developed by other institutions. These models were constructed in a systematic way using GEM tools, such as the Catalogue, Hazard Modeller, Fault, Subduction, and Ground Motion toolkits. These tools help facilitate model construction, allowing the hazard modeler to apply commonly used methods when developing seismic hazard models.

Modern PSHA models are complicated, and may involve many types of seismic sources to most accurately represent the occurrence of seismicity in a region. Furthermore, important concepts such as Ground Motion Prediction Equations (GMPEs), which indicate how the earth shakes in response to seismicity, and Magnitude-Frequency Distributions (MFDs), which describe the frequency of earthquakes of different sizes in a region or on a fault, are not always well explained, and the science behind them is evolving rapidly.

We have created several pages below that discuss these concepts, and what are the best practices and tools that we use when we build models here at GEM. Please read about the topics below:

• Characterizing and modeling fault sources
• Characterizing and modeling subduction zones
• Distributed Seismicity Sources
• Characterization and processing of seismic catalogs
• Ground Motion Prediction Equations
• Magnitude-Frequency Distributions