Near-fault Strong-motion of the 2023 Mw7.8 Kahramanmaraş Earthquake: Insights Into High-frequency Radiation Mechanisms
Description:
Classic earthquake models can accurately explain the seismic wavefield below an earthquake’s corner frequency. However, at higher frequencies, seismic radiation exhibits significantly more complex and stochastic characteristics. While various types of on-fault and off-fault complexity have been proposed to generate high-frequency radiation, their respective contributions and trade-offs remain the subject of ongoing debate.
The 2023 Mw 7.8 Kahramanmaraş earthquake provides a unique dataset to explore high-frequency radiation mechanisms. It was well recorded by a regional strong-motion network operated by the Turkey Disaster and Emergency Management Authority (AFAD), including 20 strong-motion stations within 10 km of the East Anatolian Fault. These near-fault stations, evenly distributed along the fault strike, captured seismic radiation emanating from the rupture front as it propagated southward.
In this study, we investigate the high-frequency characteristics of the Mw 7.8 southern rupture using these 20 near-fault strong motion stations. We find that most high-frequency signal energy arrives at these stations alongside the low-frequency signals, suggesting that the high-frequency radiation is generated near the fault rather than by medium scattering. Compared to their lower-frequency counterparts, seismic radiations above ~0.4 Hz display distinct characteristics: high-frequency signals do not maintain discernible radiation patterns, and the two horizontal components lose correlation, suggesting there may be multiple phases with different origins arriving simultaneously. Comparison with regional stations and back-projection analysis suggests that high-frequency generation information may be preserved even at distant stations.
Our findings imply a need to update our current earthquake source representations for modeling high-frequency radiations. The results of this study may provide valuable constraints for future theoretical work aimed at distinguishing different high-frequency radiation mechanisms.
Session: Accuracy and Variability of Physics-based Ground Motion Modeling [Poster]
Type: Poster
Date: 4/15/2025
Presentation Time: 08:00 AM (local time)
Presenting Author: Baoning
Student Presenter: No
Invited Presentation:
Poster Number: 90
Authors
Baoning Wu Presenting Author Corresponding Author baw011@ucsd.edu University of California, San Diego |
Bo Li bo.li.3@kaust.edu.sa King Abdullah University of Science and Technology |
Hao Zhang hzhang63@usc.edu University of Southern California |
Shuye Huang shuye.huang@usc.edu University of Southern California |
Guoliang Li guolingl@usc.edu Central South University |
Alice-Agnes Gabriel algabriel@ucsd.edu University of California, San Diego |
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Near-fault Strong-motion of the 2023 Mw7.8 Kahramanmaraş Earthquake: Insights Into High-frequency Radiation Mechanisms
Session
Accuracy and Variability of Physics-based Ground Motion Modeling