Overall subshear but locally supershear rupture of the 2021 Mw 7.4 Maduo earthquake from high-rate GNSS waveforms and three-dimensional InSAR deformation

Lyu，Mingzhe; Chen，Kejie; Xue，Changhu; Zang，Nan; Zhang，Wei; Wei，Guoguang

2022-09-20

10.1016/j.tecto.2022.229542

TECTONOPHYSICS   Impact Factor & Quartile

0040-1951

1879-3266

An M 7.4 left-lateral earthquake hit Maduo County in Qinghai province, China, on 21 May 2021. In this paper, we combined the 1-Hz global navigation satellite system (GNSS) displacement waveforms, GNSS static offsets and the three-dimensional (3D) co-seismic deformation field from the interferometric synthetic radar (InSAR) measurements to estimate the source kinematics of this event. Our results reveal that there was about 160 km of surface ruptures with varying strike angles, and the earthquake propagated bilaterally, with the bulk of the slip formed to the southeast of the epicenter. Substantial slip occurred to a depth of ~6 km, and the estimated maximum slip was ~5 m. The source time function presents a ~ 35-s total duration with two peaks, and the total geodetic seismic moment is 1.61 × 10 Nm (equivalent to M 7.4). The near-field high-rate GNSS waveforms inversion results indicate that this earthquake is an overall subshear but locally supershear rupture event. The preferred average rupture velocity is 2.8 km/s while the velocities to the southeast and northwest of epicenter are 3.8 and 2.2 km/s, respectively. Supershear enhanced ground motion and simulation using the 3D curvilinear grid finite-difference method shows the acceleration caused by the earthquake exceeded the building code limits for bridges that collapsed due to strong ground shaking. Furthermore, this earthquake increased the stress level of the Maqin–Maqu segment of the East Kunlun Fault, and was also responsible for an off-fault aftershock sequence at the northwest end of the earthquake rupture.

2021 Mw 7.4 Maduo earthquake 3D deformation High-rate GNSS waveforms Locally supershear

SCI ; EI

English

First ; Corresponding

National Natural Science Foundation of China[42074024];National Natural Science Foundation of China[U1901602];

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000860273300003

ELSEVIER

20223512646412

Codes (symbols) ; Faulting ; Finite difference method ; Global positioning system ; Synthetic aperture radar

Earthquake Measurements and Analysis:484.1 ; Radar Systems and Equipment:716.2 ; Data Processing and Image Processing:723.2 ; Numerical Methods:921.6

GEOSCIENCES

2-s2.0-85136563648

Scopus

Department of Earth and Space Sciences,Southern University of Science and Technology,Shenzhen,518055,China

Lyu，Mingzhe,Chen，Kejie,Xue，Changhu,et al. Overall subshear but locally supershear rupture of the 2021 Mw 7.4 Maduo earthquake from high-rate GNSS waveforms and three-dimensional InSAR deformation[J]. TECTONOPHYSICS,2022,839.

Lyu，Mingzhe,Chen，Kejie,Xue，Changhu,Zang，Nan,Zhang，Wei,&Wei，Guoguang.(2022).Overall subshear but locally supershear rupture of the 2021 Mw 7.4 Maduo earthquake from high-rate GNSS waveforms and three-dimensional InSAR deformation.TECTONOPHYSICS,839.

Lyu，Mingzhe,et al."Overall subshear but locally supershear rupture of the 2021 Mw 7.4 Maduo earthquake from high-rate GNSS waveforms and three-dimensional InSAR deformation".TECTONOPHYSICS 839(2022).