Could thermal pressurization have induced the frequency-dependent rupture during the 2019 M(w)8.0 Peru intermediate-depth earthquake?

Luo, Heng1; Zeng, Hongyu2; Shi, Qibin2; Wang, Teng1; Liao, Mingsheng3; Hu, Jiashun4; Wei, Shengji2,5

2022-09-15

10.1093/gji/ggac329

GEOPHYSICAL JOURNAL INTERNATIONAL   Impact Factor & Quartile

0956-540X

1365-246X

The rupture process of earthquakes at intermediate-depth (similar to 70-300 km) have rarely been illuminated by a joint analysis of geodetic and seismic observations, hindering our understanding of their dynamic rupture mechanisms. Here we present detailed rupture process of the 2019 M(w)8.0 Peru earthquake at the depth of 122 km depth, derived with a holistic approach reconciling InSAR and broad-band seismic waveform data. The joint inversion of InSAR observations and teleseismic body waves results in a finite rupture model that extends similar to 200 km along strike, with unilateral rupture towards north that lasted for similar to 60 s. There are four major slip patches in the finite fault model which are well corresponding to the position and timing of the sources in back-projection and multiple points source results. The largest slip patch, which occurred similar to 40 s after the rupture initiation, had a longer and smoother rise time, and radiated much weaker high-frequency seismic waves compared to other smaller slip patches. This distinct frequency-dependent rupture could be explained by a strong dynamic weakening mechanism. We question whether thermal pressurization of pore free water rather than thermal run away could be such a mechanism. Our frequency content analysis could be generalized to study other earthquakes including those deeper than 300 km.

Satellite geodesy Joint inversion Earthquake dynamics Earthquake source observations Subduction zone processes

SCI

English

Others

NSFC[41974017] ; EOS internal research grant[04MNS001909A620] ; Singapore MOE tier-2 grant[MOE2019-T2-1-182]

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000853930000009

OXFORD UNIV PRESS

GEOSCIENCES

Web of Science

1.Peking Univ, Sch Earth & Space Sci, Beijing 100084, Peoples R China
2.Nanyang Technol Univ, Asian Sch Environm, 62 Nanyang Dr, Singapore 637459, Singapore
3.Wuhan Univ, State Key Lab Nformat Engn Surveying Mapping & Re, Wuhan 430072, Hubei, Peoples R China
4.Southern Univ Sci & Technol, Dept Earth & Space Sci, Shenzhen 518055, Guangdong, Peoples R China
5.Nanyang Technol Univ, Earth Observ Singapore, Singapore 639798, Singapore

Luo, Heng,Zeng, Hongyu,Shi, Qibin,et al. Could thermal pressurization have induced the frequency-dependent rupture during the 2019 M(w)8.0 Peru intermediate-depth earthquake?[J]. GEOPHYSICAL JOURNAL INTERNATIONAL,2022,232(1).

Luo, Heng.,Zeng, Hongyu.,Shi, Qibin.,Wang, Teng.,Liao, Mingsheng.,...&Wei, Shengji.(2022).Could thermal pressurization have induced the frequency-dependent rupture during the 2019 M(w)8.0 Peru intermediate-depth earthquake?.GEOPHYSICAL JOURNAL INTERNATIONAL,232(1).

Luo, Heng,et al."Could thermal pressurization have induced the frequency-dependent rupture during the 2019 M(w)8.0 Peru intermediate-depth earthquake?".GEOPHYSICAL JOURNAL INTERNATIONAL 232.1(2022).