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Spatio-Temporal Slip Distributions of Deep Short-Term Slow Slip Events in the Nankai Subduction Zone Using Gnss, Tilt, and Strain Data

Description: 

Slow slip events (SSEs) have been repeatedly observed on the deep plate interface at ~30-40 km depth in the Nankai subduction zone, Japan. These SSEs have been monitored using three types of geodetic data: GNSS, tilt, and strain. GNSS has strength in their station density, whereas its sensitivity to crustal deformation is lower than tilt and strain. Tilt and strain has strength in their sensitivity to crustal deformation, but their station is much less than GNSS. In addition, tilt and strain has unique noise like Brownian motion, which makes us difficult to analyze those data. In this study, we develop the integrated inversion method using the three types of data for spatio-temporal slip distributions of deep SSEs in the Nankai subduction zone.

We first test the performance of the developed method using synthetic datasets. We calculated crustal deformation due to synthetic SSEs in the Shikoku region with three different magnitudes (Mw 5.7, 6.0, and 6.3). We also calculate synthetic observation noise (Gaussian noise for GNSS and Brownian noise for tilt and strain). The summed signals of these two synthetic values are considered as pseudo-observation, and we applied the developed method. We tested all possible combinations of data types and checked whether the assumed spatio-temporal slip distributions are well reproduced. We tested the resolution of the developed method using checkerboard test as well. We will also report preliminary results for real data application in the Shikoku region.

Session: Characteristics and Mechanics of Fault Zone Rupture Processes, from Micro to Macro Scales - I

Type: Oral

Date: 5/2/2024

Presentation Time: 09:00 AM (local time)

Presenting Author: Suguru

Student Presenter: No

Invited Presentation: 

Authors