Overlapping Regions of Coseismic and Transient Slow Slip on the Hawaiian Décollement

Session: From Aseismic Deformation to Seismic Transient Detection, Location and Characterization [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: Earthquakes and slow slip are different faulting processes that release accumulated stress on different time scales. Earthquakes or fast slip, grow and cease rapidly in seconds to minutes. In contrast, slow slip typically occurs on timescales of days to months. Despite nearly two decades of study, it’s still unclear whether the same section of fault is capable of hosting both slow, aseismic and fast, seismic slip. Here, we jointly invert the GPS, strong motion data and empirically corrected tsunami waveforms for the 2018 M7.1 Hawaii earthquake. We examine the inversion parameters for the earthquake and revisit the inversion of a previously well discovered SSEs in the adjacent area. We grid-search the possible fault plane and regularizations of the inversion and find strong evidence of overlapping regions of coseismic and slow slip. We also perform numerical modeling to simulate the fast and slow slip behavior. Due to the homogeneity of the Hawaiian décollement, differences in effective stress, are likely an important factor that causes the diversity of slip. We find that an earthquake can completely penetrate into the slow slip zone provided the effective stress differences between fast and slow slip zones is large enough to facilitate this. Our result reinforces the idea that an individual section of fault is capable of hosting a variety of distinct slip behaviors. This is important for estimating earthquake rupture extent and for ground motion and tsunami hazard assessment.

Presenting Author: Jiun-Ting Lin

Authors