Laboratory earthquakes decipher control and stability of rupture speeds

Peng Dong; Kaiwen Xia; Ying Xu; Derek Elsworth; Jean-Paul Ampuero

doi:10.1038/s41467-023-38137-w

Laboratory earthquakes decipher control and stability of rupture speeds

Nat Commun. 2023 Apr 27;14(1):2427. doi: 10.1038/s41467-023-38137-w.

Authors

Peng Dong¹, Kaiwen Xia^{2

3

4}, Ying Xu⁵, Derek Elsworth⁶, Jean-Paul Ampuero⁷

Affiliations

¹ Institute of Geosafety, School of Engineering and Technology, China University of Geosciences, Beijing, 100083, China.
² Institute of Geosafety, School of Engineering and Technology, China University of Geosciences, Beijing, 100083, China. kaiwen.xia@utoronto.ca.
³ Department of Civil and Mineral Engineering, University of Toronto, Toronto, ON, M5S 1A4, Canada. kaiwen.xia@utoronto.ca.
⁴ State Key Laboratory of Hydraulic Engineering Simulation and Safety, School of Civil Engineering, Tianjin University, Tianjin, 300072, China. kaiwen.xia@utoronto.ca.
⁵ State Key Laboratory of Hydraulic Engineering Simulation and Safety, School of Civil Engineering, Tianjin University, Tianjin, 300072, China.
⁶ Energy and Mineral Engineering & Geosciences, G3 Center and EMS Energy Institute, Pennsylvania State University, University Park, PA, 16802, USA.
⁷ Géoazur, Université Côte d'Azur, IRD, CNRS, Observatoire de la Côte d'Azur; 250 rue Albert Einstein, 14 Sophia Antipolis, 06560, Valbonne, France.

Abstract

Earthquakes are destructive natural hazards with damage capacity dictated by rupture speeds. Traditional dynamic rupture models predict that earthquake ruptures gradually accelerate to the Rayleigh wave speed with some of them further jumping to stable supershear speeds above the Eshelby speed (~[Formula: see text] times S wave speed). However, the 2018 M_w 7.5 Palu earthquake, among several others, significantly challenges such a viewpoint. Here we generate spontaneous shear ruptures on laboratory faults to confirm that ruptures can indeed attain steady subRayleigh or supershear propagation speeds immediately following nucleation. A self-similar analysis of dynamic rupture confirms our observation, leading to a simple model where the rupture speed is uniquely dependent on a driving load. Our results reproduce and explain a number of enigmatic field observations on earthquake speeds, including the existence of stable subEshelby supershear ruptures, early onset of supershear ruptures, and the correlation between the rupture speed and the driving load.

Abstract

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