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Published January 16, 2020 | Supplemental Material + Submitted + Published
Journal Article Open

Does a Damaged-Fault Zone Mitigate the Near-Field Impact of Supershear Earthquakes?—Application to the 2018 M_w 7.5 Palu, Indonesia, Earthquake


The impact of earthquakes can be severely aggravated by cascading secondary hazards. The 2018 M_w 7.5 Palu, Indonesia, earthquake led to devastating tsunamis and landslides, while triggered submarine landslides possibly contributed substantially to generate the tsunami. The rupture was supershear over most of its length, but its speed was unexpectedly slow for a supershear event, between the wave velocity V_s and Eshelby's speed √2V_s, an unstable speed range in conventional theory. Here, we investigate whether dynamic rupture models including a low‐velocity fault zone can reproduce such a steady supershear rupture with a relatively low speed. We then examine numerically how this peculiar feature of the Palu earthquake could have affected the near‐field ground motion and thus the secondary hazards. Our findings suggest that the presence of a low‐velocity fault zone can explain the unexpected rupture speed and may have mitigated the near‐field ground motion and the induced landslides in Palu.

Additional Information

© 2020 American Geophysical Union. Received 2 OCT 2019; Accepted 23 DEC 2019; Accepted article online 3 JAN 2020. This work was supported by the French National Research Agency (ANR) through project FAULTS_R_GEMS (Grant ANR‐17‐CE31‐0008) and Investments‐in‐the‐Future project UCAJEDI (Grant ANR‐15‐IDEX‐01). We acknowledge Luis A. Dalguer for helpful comments that improved the content of this manuscript. All data needed to reproduce this work are available online: 2‐D and 3‐D wave propagation modeling tools can be found at the websites (https://github.com/jpampuero/sem2dpack and https://github.com/geodynamics/specfem3d).

Attached Files

Published - Oral_et_al-2020-Geophysical_Research_Letters.pdf

Submitted - Palu_paper_GRL_preprint.pdf

Supplemental Material - grl60058-sup-0001-2019gl085649-figure_si-s01.pdf


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