EGU21-4332, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-4332
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

A transient in surface motions dominated by deep afterslip subsequent to a shallow supershear earthquake: the 2018 Mw 7.5 Palu case.

Nicolai Nijholt1,2, Wim Simons2, Joni Efendi3, Dina Sarsito4, and Riccardo Riva1
Nicolai Nijholt et al.
  • 1Delft University of Technology, Faculty of Civil Engineering and Geosciences, Geosciences and Remote Sensing, Delft, Netherlands
  • 2Delft University of Technology, Faculty of Aerospace Engineering, Astrodynamics and Space Missions, Delft, Netherlands
  • 3BIG (Badan Informasi Geospasial/Geospatial Information Agency), Java, Indonesia
  • 4ITB (Institut Teknologi Bandung/Institute of Technology Bandung), Geodesy Research Group, Faculty of Earth Sciences and Technology, Bandung, Java, Indonesia

The 2018 Mw 7.5 Palu earthquake is a remarkable strike-slip event due to its nature as a shallow supershear fault rupture across several segments and a destructive tsunami that followed co-seismic deformation. GPS offsets in the wake of the 2018 earthquake display a transient in the surface motions of northwest Sulawesi. A Bayesian approach identifies (predominantly a-seismic) deep afterslip on and below the co-seismic rupture plane as the dominant physical mechanism causing the cumulative, post-seismic, surface displacements whereas viscous relaxation of the lower crust and poro-elastic rebound contribute negligibly. We confirm a correlation between shallow supershear rupture and post-seismic surface transients with afterslip activity in the zone below an inter-seismically locked fault plane where the slip rate tapers from zero to creeping.

How to cite: Nijholt, N., Simons, W., Efendi, J., Sarsito, D., and Riva, R.: A transient in surface motions dominated by deep afterslip subsequent to a shallow supershear earthquake: the 2018 Mw 7.5 Palu case., EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-4332, https://doi.org/10.5194/egusphere-egu21-4332, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.