WITHDRAWN Seismic Activity and Earthquake Interaction in the Mentawai Seismic Gap (2022–2023): Source Characteristics and Potential for Future Large Ruptures
Description:
WITHDRAWN In 2022–2023, there was significant increase in seismic activity in the Mentawai Seismic Gap Zone, located in the Sumatra subduction zone, Indonesia. The series of earthquakes formed a cluster and ruptured a segment that has not experienced a large earthquake (Mw > 8) since 1797 (near Siberut Island). Two earthquakes with magnitudes greater than Mw 6.5 were analyzed for source characteristics: the Mw 6.7 earthquake on March 13, 2022, and the Mw 7.1 earthquake on April 24, 2023. We conducted finite-fault analysis using the kinematic slip method, incorporating both teleseismic and strong-motion data. We also modeled Coulomb stress changes to investigate the interaction between these earthquakes. Both of these thrust earthquakes have strike directions close to 325°, with dips of 19° and 12° respectively, consistent with the Sumatra subduction segment of Mentawai. Our results indicate that the Mw 6.7 event ruptured at a depth of 22–32 km (centroid = 30 km) with an effective rupture dimension of 20 × 11 km and a slip of approximately 15–60 cm. The Mw 7.1 event occurred at a narrower depth of 10–18 km (centroid = 15 km), with an effective rupture dimension of 35 × 20 km and a slip of approximately 30–60 cm. Both earthquakes exhibited upward rupture propagation and released seismic energy through a single asperity mechanism. The Mw 7.1 event occurred in increased stress field generated by the Mw 6.7 event. Then the stress pertubation could potentially trigger larger earthquakes in the southern region, an area with high interseismic coupling. The total seismic energy released by the 2022–2023 earthquake sequence represents only a small reduction in the accumulated moment deficit since the last great rupture. These findings suggest that the Mentawai segment, especially its northern part, still has the potential to rupture with an Mw > 8 earthquake in the future.
Session: Earth’s Structure from the Crust to the Core [Poster]
Type: Poster
Date: 4/16/2025
Presentation Time: 08:00 AM (local time)
Presenting Author: Renhard
Student Presenter: Yes
Invited Presentation:
Poster Number: 105
Authors
Renhard Sipayung Presenting Author Corresponding Author renhardspy@gmail.com Indonesian Agency for Meteorology, Climatology and Geophysics |
Mohammad Syamsu Rosid syamsu.rosid@gmail.com University of Indonesia |
Titi Anggono titi.anggono@gmail.com National Research and Innovation Agency of Indonesia |
Dimas Sianipar dimas.salomo@gmail.com Indonesian Agency for Meteorology, Climatology and Geophysics |
Agus Riyanto agus.riyanto@bmkg.go.id Indonesian Agency for Meteorology, Climatology and Geophysics |
Setyoajie Prayoedhie setyoajie.p@icloud.com Indonesian Agency for Meteorology, Climatology and Geophysics |
Daryono Daryono daryonobmg@gmail.com Indonesian Agency for Meteorology, Climatology and Geophysics |
Nelly Florida Riama nelly.florida@bmkg.go.id Indonesian Agency for Meteorology, Climatology and Geophysics |
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WITHDRAWN Seismic Activity and Earthquake Interaction in the Mentawai Seismic Gap (2022–2023): Source Characteristics and Potential for Future Large Ruptures
Category
Earth’s Structure from the Crust to the Core