Probing Transient Rheology and Spatial Heterogeneity of Faults Using Repeating Earthquakes and Deformation Data
Description:
Fault zone rheology and heterogeneity have fundamental controls on earthquakes and fault behavior. Constraining these intrinsic fault properties requires high-resolution geophysical observations and faces enduring challenges due to a lack of in-situ measurements and validations. Here we use continuous seismic and geodetic observations following the 2004 Mw6.0 Parkfield earthquake of the San Andreas fault to image rapidly evolving transient faulting processes and thereby constrain fault zone rheology and heterogeneity. For seismic observables, we compare several characteristically repeating earthquake (CRE) catalogs to obtain refined event identification and estimate the in-situ fault slip history at depth assuming a model of single asperity surrounded by creep and a common scaling relation of recurrence interval and fault slip. For geodetic observables, we combine high-rate GNSS (Global Navigation Satellite System) and InSAR time series (Interferometric Synthetic Aperture Radar) displacement data. To optimize the disparate and yet complimentary spatiotemporal resolutions of GNSS and InSAR, we design a new two-step strategy to retain the GNSS-based high temporal resolution of finite-fault afterslip models while incrementally ingesting additional spatial constraints from less-frequently sampled, high-density InSAR deformation fields. We compare and reconcile the two independent approaches, based on the CRE scaling and geodetic finite-fault slip models, to estimate spatially- and temporally-varying postseismic fault slip history in the seismogenic crust. The derived or inferred fault slip histories are used to estimate the rheological laws and parameters for fault zones based on theoretical models. The along-dip and lateral variations of fault properties, along with discrepancies in seismic and geodetic estimates, help us further interpret the heterogeneous state of fault zones.
Session: Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales [Poster Session]
Type: Poster
Date: 5/2/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Junle
Student Presenter: No
Invited Presentation:
Authors
Junle Jiang Presenting Author Corresponding Author jiang@ou.edu University of Oklahoma |
Taka’aki Taira taira@berkeley.edu University of California, Berkeley |
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Probing Transient Rheology and Spatial Heterogeneity of Faults Using Repeating Earthquakes and Deformation Data
Category
Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales