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- Title
Effect of Merging Multiscale Models on Seismic Wavefield Predictions Near the Southern San Andreas Fault.
- Authors
Ajala, R.; Persaud, P.
- Abstract
Updating Earth models used by the scientific community in geologic studies and hazard assessment has a significant societal impact but is computationally prohibitive due to the large spatial scale. The advent of urban seismology allowed rapid development of local high‐resolution models using short‐term dense seismic arrays to become conventional. To incorporate the details in these local models in community models, we developed a technique for constructing window taper functions like the cosine taper in arbitrarily shaped spatial domains on regular grids. We apply our algorithm to the problem of low‐frequency ground shaking estimation near the southernmost San Andreas fault by creating two hybrid models. These models consist of basin‐scale (top 10 km or less) high‐resolution models developed using controlled source data embedded into two popular Southern California Earthquake Center community models. We evaluate the models by computing long period (6–30 s) wavefield energy misfits using 11 earthquakes with moment magnitudes between 3.5 and 5.5 not used in developing any of the models under consideration. One of the hybrid models produces an ∼24% decrease while the other has an ∼0.6% increase in the overall median misfit relative to their original community models. The overlapping misfit values between the models and variability in waveform fit for different events and stations emphasize the difficulties in model validation. Our approach can merge any type of gridded multiscale and multidimensional datasets, and represents a valuable tool for modeling in the computational sciences. Plain Language Summary: Earth models are helpful to society and play an essential role in exploring for natural resources, geologic hazard assessments, and understanding how our planet works. The models are developed in various scales ranging from the entire Earth to a metropolitan area. It tends to be the case that the bigger models are more expensive to create, especially with cutting‐edge methods. We experiment with a simple technique for updating big models by replacing the most critical parts with smaller, more accurate models. When we test our new tool for earthquake ground motion prediction, we achieve some results that show that it can be useful. Key Points: We develop an algorithm for merging gridded multiscale and multidimensional datasets and smoothly embed basin models in two regional modelsOne hybrid model produces an ∼24% decrease and the other has an ∼0.6% increase in median waveform misfit relative to their regional modelsMisfit overlap and variability with stations and events between models show the complexities of model validation
- Subjects
SEISMOLOGY; SEISMIC waves; SEISMIC arrays; GEOPHYSICAL instruments; SOUTHERN California Earthquake Center
- Publication
Journal of Geophysical Research. Solid Earth, 2021, Vol 126, Issue 10, p1
- ISSN
2169-9313
- Publication type
Article
- DOI
10.1029/2021JB021915