Revised GNSS-Only Dislocation Models and Residual Analysis for Ridgecrest Sequence, San Simeon, Parkfield and La Habra Events

Session: Observations From the 2019 Ridgecrest Earthquake Sequence [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Recent advances in postprocessing networks of GNSS daily time series have yielded low-noise estimates of motions with 1-sigma error on the order of 0.36 mm, 0.34 mm, and 1.4 mm (E, N, U)for a jump estimate using a 17 day event-centered window. This precision is maintained for large earthquake jumps through removal of an estimated common mode error time series based on distant station time series, fully separating the earthquake event from the network common mode. Maintenance of such precision allows reexamination of past seismic events and secondary phenomena associated with aftershocks and aseismic post event motions.

We employ an improved version of the GeoGateway Downhill Simplex method to perform uniform rectangular dislocation inversions of GNSS jumps and rapid postseismic deformation. While simple, models produced by these inversions provide a basic picture of the earthquake event, parameters for spatial interpolation of deformation (particularly important for Deep Space Network sites), a dense deformation field for simulated interferograms, and residuals that may indicate additional deformation sources. We provide these GNSS-only cleaned observations and inversion models for the Ridgecrest 2019 sequence, with suggestive deformation patterns found near the Garlock fault, the San Andreas Fault area near Parkfield, the Long Valley Caldera, and the margins of the San Gabriel Mountains and the Inyo mountains. We present revised best-fit uniform-slip elastic models and residual analysis for past California earthquakes, including San Simeon 2003, Parkfield 2004, and La Habra 2014.

Presenting Author: Jay Parker

Authors