EGU21-1759, updated on 03 Mar 2021
https://doi.org/10.5194/egusphere-egu21-1759
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Rupture process of the 7 May 2020 Mw 5.0 Tehran earthquake and its relation with the Damavand stratovolcano, and Mosha Fault

Pınar Büyükakpınar1, Mohammadreza Jamalreyhani2, Mehdi Rezapour2, Stefanie Donner3, Nima Nooshiri4, Mirali Hassanzadeh5, Pouria Marzban6, and Behnam Maleki Asayesh7
Pınar Büyükakpınar et al.
  • 1Kandilli Observatory and Earthquake Research Institute (KOERI), Boğaziçi University, Istanbul, Turkey
  • 2Institute of Geophysics, University of Tehran, Iran
  • 3Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany
  • 4Dublin Institute for Advanced Studies, Geophysics Section, Dublin, Ireland
  • 5Department of Earth Sciences, Institute for Advanced Studies in Basic Sciences, Zanjan, Iran
  • 6GFZ German Research Centre for Geosciences, Potsdam, Germany
  • 7International Institute of Earthquake Engineering and Seismology, Tehran, Iran

In May 2020 an earthquake with Mw 5.0 struck at ~40 km east of Tehran metropolis and ~15 km south of the Damavand stratovolcano. It was responsible for 2 casualties and 23 injured. The mainshock was preceded by a foreshock with Ml 2.9 and followed by a significant aftershock sequence, including ten events with Ml 3+. The occurrence of this event raised the question of its relation with volcanic activities and/or concern about the occurrence of larger future earthquakes in the capital of Iran. Tehran megacity is surrounded by several inner-city and adjacent active faults that correspond to high-risk seismic sources in the area. The Mosha fault with ~150 km long is one of the major active faults in central Alborz and east of Tehran. It has hosted several historical earthquakes (i.e. 1665 Mw 6.5 and 1830 Mw 7.1 earthquakes) in the vicinity of the 2020 Mw 5.0 Tehran earthquake’s hypocenter. In this study, we evaluate the seismic sequence of the Tehran earthquake and obtain the full moment tensor inversion of this event and its larger aftershocks, which is a key tool to discriminate between tectonic and volcanic earthquakes. Furthermore, we obtain a robust characterization of the finite fault model of this event applying probabilistic earthquake source inversion framework using near-field strong-motion records and broadband seismograms, with an estimation of the uncertainties of source parameters. Due to the relatively weak magnitude and deeper centroid depth (~12 km), no static surface displacement was observed in the coseismic interferograms, and modeling performed by seismic records. Focal mechanism solution from waveform inversion, with a significant double-couple component, is compatible with the orientation of the sinistral north-dipping Mosha fault at the centroid location. The finite fault model suggests that the mainshock rupture propagated towards the northwest. This directivity enhanced the peak acceleration in the direction of rupture propagation, observed in strong-motion records. The 2020 moderate magnitude earthquake with 2 casualties, highlights the necessity of high-resolution seismic monitoring in the capital of Iran, which is exposed to a risk of destructive earthquakes with more than 10 million population. Our results are important for the hazard and risk assessment, and the forthcoming earthquake early warning system development in Tehran metropolis.

How to cite: Büyükakpınar, P., Jamalreyhani, M., Rezapour, M., Donner, S., Nooshiri, N., Hassanzadeh, M., Marzban, P., and Maleki Asayesh, B.: Rupture process of the 7 May 2020 Mw 5.0 Tehran earthquake and its relation with the Damavand stratovolcano, and Mosha Fault, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-1759, https://doi.org/10.5194/egusphere-egu21-1759, 2021.

Corresponding presentation materials formerly uploaded have been withdrawn.