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The Kahramanmaras (Turkey) Earthquake Multiplet Sequence Revealed by Deep Learning Computer Vision

Description: 

The February 6, 2023 Kahramanmaras (Turkey) earthquake multiplet involved two mainshocks ~9 hours apart on neighboring faults within the Arabia-Anatolia collision. The first M 7.8 event, the largest ever recorded on the East Anatolian Fault, and the subsequent M 7.6 event, collectively resulted in over 50,000 fatalities. Accurately detailing this earthquake multiplet sequence, including the interval between the two mainshocks as well as subsequent aftershocks, is important for advancing our understanding of seismogenic processes and regional tectonics, which in turn underpin earthquake science and hazard mitigation. Deep learning is becoming a powerful tool for seismological analysis, and our new algorithm, the Source Untangler Guided by Artificial intelligence image Recognition (SUGAR) (Tan et al., submitted), has proven to outperform skillful human analysts and popular AI and non-AI workflows in delineating complex earthquake sequences. SUGAR applies a 3D computer vision technique to the brightness video produced by the Source-Scanning Algorithm (Kao and Shan, 2004), guiding the phase association and making it possible to locate small events with poorly discernible waveforms, even when occurring concurrently. In this study, we retrain a SUGAR model with seismic stations in Turkey and apply it to the Kahramanmaras earthquake sequence from before the first mainshock to the end of April 2023. SUGAR’s unusual ability at untangling complex signals is especially valuable in the early stage of the sequence, such as the ~9-hour interval between mainshocks. The SUGAR catalog has ~6 times as many events as the routine KOERI catalog. Results indicate that the first M 7.8 earthquake initiated on a secondary, west-dipping fault branch and propagated to the main subvertical East Anatolian Fault. The M 7.8 mainshock rupture terminated short of the 2020 M 6.8 Elazig earthquake, but remote aftershocks were triggered on the NE side of the 2020 rupture. The M 7.6 earthquake ruptured the Savrun-Cardak fault, but left a clear gap between it and the M 7.8 earthquake.

Session: Illuminating Complex, Multiplet Earthquake Sequences at Kahramanmaras (Turkiye), Herat (Afghanistan), and Beyond - I

Type: Oral

Date: 5/2/2024

Presentation Time: 08:30 AM (local time)

Presenting Author: Fengzhou

Student Presenter: Yes

Invited Presentation: 

Authors