A Suite of Spatially Correlated Random Fields of Earthquake Ground Motion in Terms of 1-second Spectral Acceleration Response

Recent earthquake ground motion prediction equations generally treat the earthquake ground motion field as random, conditioned on a few parameters. These givens mostly include earthquake magnitude, fault rupture mechanism, seismic domain (meaning plate boundary or shield), and spatially varying site conditions such as average shearwave velocity in the upper 30 meters of soil. The ground motion field exhibits spatial correlation: places that are closer together tend to have more similar motion. That spatial correlation can matter to the probability distribution of the aggregate monetary or non-monetary loss experienced by a portfolio of assets, especially if high-value assets can be located within a few kilometers of each other. In a related work (Porter et al. submitted 2023), we estimated the probability distribution of portfolio loss in earthquakes, and therefore wanted to account for the spatial correlation in ground motion. To do so, we generated 100 realizations of a spatially correlated random field, square, 800 km by 800 km. Spatial correlation reflects that of 5%-damped, 1-second spectral acceleration response, using the spatial correlation coefficient recommended by Jayaram and Baker (2009). The present work offers those 100 simulated random fields in the form of 100 comma-separated value (CSV) files. See the readme file included with the CSV files for details, including the full bibliographic reference for Jayaram and Baker (2009). Here is the reference for Porter et al. (submitted 2023):

Porter, K., Milner, K., and Field, E. (submitted 2023). Trimming the UCERF3-TD logic tree: model order reduction for an earthquake rupture forecast considering loss exceedance. Earthquake Spectra. Submitted Sept. 8, 2023.