Data and Models for "Coevolving Early Afterslip and Aftershock Signatures of a San Andreas Fault Rupture"

The original GPS solutions are processed and archived at the Scripps Orbit and Permanent Array Center (SOPAC) (http://sopac-csrc.ucsd.edu/).

You can access the following FTP directory (username: “anonymous”; password: your email) to obtain high-rate (1Hz) GPS solutions for the Parkfield earthquake:

http://garner.ucsd.edu/pub/measuresESESES_products/EarthquakeDisplacements/Parkfield_20040928/GNSS/JiangBockKlein2021

The archive contains the following datasets and modeling files:

1. High-rate (1Hz) GPS solutions with sidereal filtering

The post-processed high-rate GPS solutions for 13 stations from September 22 to October 5, 2004 are provided in separate files. The four columns are for the time (in seconds) relative to the Parkfield earthquake initiation time (17:15:24 UTC, September 28, 2004), the east, north, and vertical components (in mm) of the displacements. “NaN” values indicate data gaps or removed outliers.

2. Daily GPS solutions with corrections for the 2003 San Simeon Earthquake

The post-processed daily solutions for 13 stations up till May 2019 are provided in separate files, following the same format as high-rate solutions.

3. Downsampled GPS solutions

The cumulative GPS displacements and error estimates for coseismic and postseismic periods are provided in separate files. The file “displacement_coseismic.txt” has station ID, east, north, and vertical displacement components (in mm), and their error estimates (in mm) in columns. The file “displacement_postseismic.txt” has station ID, postseismic time (relative to the Parkfield earthquake initiation time), east, north, and vertical displacement components (in mm), and their error estimates (in mm) in columns; every block of 13 rows indicates displacements at 13 stations for each epoch.

4. Fault geometry for the SAF and SWFZ

The geometries for the San Andreas Fault (SAF) and Southwest Fracture Zone (SWFZ) are provided in two formats. The “*lonlat.txt” files show the longitude, latitude, depth (km), strike angle (degree), dip angle (degree), area (km²), length (km), width (km), and index (starting from 0) for each fault patch in columns. The “*GMT.txt” files show the fault geometry in GMT format.

5. Fault slip models and uncertainty estimates

The strike-slip and dip-slip components (in mm) and their uncertainty estimates are provided in separate files for the coseismic period (“step0”) and cumulative postseismic periods (“step1…44”). Step0–26 models use the SWFZ fault geometry and step27–44 models use the SAF fault geometry. The time information is indicated in the header. The uncertainty estimates only include the variances of the posterior variance-covariance matrix, which are available upon request to the authors.