Strength dependency of frequency-magnitude distribution in earthquakes and implications for stress state criticality.
Nat Commun
; 15(1): 4957, 2024 Jun 11.
Article
em En
| MEDLINE
| ID: mdl-38862498
ABSTRACT
Earthquake size distribution is characterized by the "b-value" of the power law decay, which exhibits spatiotemporal variations. These variations are sometimes evident before a large earthquake. Understanding spatiotemporal variations is key to developing a model for large-earthquake generation. Previous studies have shown that changes in the b-value are caused by the tectonic stress regime. Furthermore, lab experiments have demonstrated the b-value dependency of acoustic emissions on the criticality of the failure condition. However, the factors controlling the b-values during natural seismic activity are unclear. In this study, changes in the b-value in small earthquake sequences are investigated, focusing on failure criticality. Based on our high-precision focal mechanism dataset, we conclude that the b-value decreases as it nears a critical failure condition, providing a physical explanation for the reduction in b-value before a major earthquake. Our findings elucidate fault failure models, facilitating improvement in earthquake alerts and disaster mitigation.
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MEDLINE
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En
Ano de publicação:
2024
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Article