An Updated San Andreas Fault Geometry in Parkfield, California
The San Andreas Fault is the most well-known fault zone in California. To better address its seismic hazard, models of specific rupture scenarios can be simulated to evaluate the possible extent of rupture propagation, slip, and ground motion. This has become especially relevant for studies with a focus on the relatively short recurrence time of repeating moderate earthquakes in the Parkfield segment. It is pertinent to perform rupture models to assess what the next Parkfield earthquake may look like and prepare for its seismic hazard across central and southern California. As an initial step in such a model, a well-constrained fault geometry is necessary. Currently, the Statewide California Earthquake Center Community Fault Model (SCEC-CFM) has a representation of the Parkfield section that may be too low resolution for use in detailed dynamic earthquake modeling. Variations in both fault strike and dip in this region must be translated as accurately as possible to computer models, since changes in geometry can strongly affect the rupture and slip process. Here, we use USGS’s earthquake catalog from 1996 to the present day (2026) to constrain the San Andreas Fault geometry at depth along the Parkfield segment. We use high order polynomials to invert for the geometry of the fault and generate a best fit surface to the data. In light of limited seismic events closest to the free-surface, we will augment our seismicity data with InSAR data. From our results we aim to produce a state-of-the-art, best-fitting fault geometry for the central San Andreas Fault, where future studies in Parkfield can be conducted including dynamic rupture models and long-term earthquake simulations.
Session: Seismotectonics of Southern and Baja California [Poster]
Type: Poster
Room: Exhibit Hall A+B
Date: 4/16/2026
Presentation Time: 08:00 AM (local time)
Presenting Author: Adam Margolis
Student Presenter: Yes
Invited Presentation:
Poster Number: 178
Additional Authors
Adam Margolis Presenting Author Corresponding Author amarg012@ucr.edu University of California, Riverside |
David Oglesby doglesby@ucr.edu University of California, Riverside |
Axel Periollat axel.periollat@ucr.edu University of California, Riverside |
Gareth Funning gareth@ucr.edu University of California, Riverside |
Li-Chieh Lin lichieh.lin1@ucr.edu University of California, Riverside |
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An Updated San Andreas Fault Geometry in Parkfield, California
Category
Seismotectonics of Southern and Baja California
Description