Fault size-dependent fracture energy explains multiscale seismicity and cascading earthquakes

• 成果类型: Article
• 署名作者: Gabriel, Alice-Agnes; Garagash, Dmitry I.; Palgunadi, Kadek H.; Mai, P. Martin
• 署名单位: University of California System; University of California San Diego; Scripps Institution of Oceanography; University of Munich; Dalhousie University; King Abdullah University of Science & Technology; Institut Teknologi Sepuluh Nopember; Swiss Federal Institutes of Technology Domain; ETH Zurich
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-8140
• DOI: 10.1126/science.adj9587
• 发表日期: 2024-07-26
• 关键词: slip-weakening distance; self-healing pulses; source parameters; stress drop; scaling relationships; 2019 ridgecrest; 1992 landers; shear; strength; ruptures

摘要

Earthquakes vary in size over many orders of magnitude, often rupturing in complex multifault and multievent sequences. Despite the large number of observed earthquakes, the scaling of the earthquake energy budget remains enigmatic. We propose that fundamentally different fracture processes govern small and large earthquakes. We combined seismological observations with physics-based earthquake models, finding that both dynamic weakening and restrengthening effects are non-negligible in the energy budget of small earthquakes. We established a linear scaling relationship between fracture energy and fault size and a break in scaling with slip. We applied this scaling using supercomputing and unveiled large dynamic rupture earthquake cascades involving >700 multiscale fractures within a fault damage zone. We provide a simple explanation for seismicity across all scales with implications for comprehending earthquake genesis and multifault rupture cascades.