Empirical laws of location and rupture time of asperities for strong ground motion prediction
Abstract The location of asperities on a fault plane, together with rupture times, has a significant influence on strong ground motion. If these positions for predicting strong ground motions of future earthquakes could be set empirically based on data from actual earthquakes, ground motions can be...
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| Main Author: | |
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| Format: | Article |
| Language: | English |
| Published: |
SpringerOpen
2025-08-01
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| Series: | Earth, Planets and Space |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s40623-025-02224-7 |
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| Summary: | Abstract The location of asperities on a fault plane, together with rupture times, has a significant influence on strong ground motion. If these positions for predicting strong ground motions of future earthquakes could be set empirically based on data from actual earthquakes, ground motions can be predicted with better accuracy and greater adherence to reality. For some earthquakes, both data and dynamic rupture simulations have shown that the time from the onset of the seismic waveform until the amplitude increases scales with the earthquake magnitude. In this study, the author extracted asperities from fault slip data inferred through waveform inversion and found that 41.0% of the earthquakes have hypocenters within the asperities. For events with no hypocenters within asperities, the asperity rupture times and distances between asperities (or maximum slip subfault) and hypocenters are proportional to the cube root of the seismic moment. It was also confirmed that this relationship is not merely attributable to an increase in fault area with the increase in earthquake magnitude. Scaling laws were also obtained for each earthquake type (inland, inter-plate, and intra-plate) and focal mechanism. The distance from the hypocenter to the asperities (or maximum slip subfault) is large for the strike-slip and inland earthquakes. Furthermore, in 76.2% of the strike-slip earthquakes and 68.3% of the inland earthquakes, the maximum slip point was located shallower than the hypocenter. In addition, 66.8% of the asperities nearest to the hypocenter are the asperities with the largest area (53.4% if single asperity cases are excluded). The percentages of maximum slip points located at the asperities nearest to the hypocenter and at the asperity with the largest area on the fault plane are 68.6% and 83.4%, respectively (56.0% and 76.7%, respectively, if single asperity cases are excluded). The empirical rules presented in this study are useful for improving the accuracy of prediction results by setting the locations of asperities and rupture times in the models used for strong ground motion prediction to match those observed in real earthquakes. Graphical Abstract |
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| ISSN: | 1880-5981 |