Seismological Characterization of the 2021 Yangbi Foreshock‐Mainshock Sequence, Yunnan, China: More than a Triggered Cascade

Abstract

Foreshocks are known as smaller earthquakes preceding the large mainshock (Jones & Molnar, 1979). Due to the neighboring location and temporal correlation, foreshocks are considered as a possible precursory phenomenon, for example, the success prediction of 1975 M w 7.0 Haicheng earthquake largely relies on the ∼1-day foreshock activity (Wang et al., 2006). Traditionally, two end-member models are proposed to explain the triggering relationship between the foreshocks and mainshock (Dodge et al., 1996): the cascade model and the pre-slip model. The cascade model describes the seismic sequence as the cascade failure of isolated asperities, where each event is triggered by the stress transfer from the previous earthquake (Ellsworth & Bulut, 2018;Felzer et al., 2004;

Foreshocks of the 2010 Mw 6.7 Yushu, China Earthquake Occurred Near an Extensional Step‐Over

“…While we did not find any direct evidence for fluid involvement, we argue that high‐fluid pressures could help in driving the Yushu foreshock‐mainshock‐aftershock sequence. This study, together with other recent studies (e.g., Doi & Kawakata, 2012; Lei et al., 2021; Liu et al., 2022; Wu et al., 2014; T. Yang et al., 2022; Yao et al., 2020; Zhou et al., 2022) indicates that foreshock sequences could be complex, and it is challenging to use them as possible warnings for upcoming large events.…”

“…This study, together with other recent studies (e.g., Doi & Kawakata, 2012;Lei et al, 2021;Liu et al, 2022;Wu et al, 2014;T. Yang et al, 2022;Yao et al, 2020;Zhou et al, 2022) indicates that foreshock sequences could be complex, and it is challenging to use them as possible warnings for upcoming large events.…”

“…Lei et al., 2021 carried out a preliminary study and found out the Yangbi foreshock sequence was largely modulated by tidal stresses, and argued that the sequence may be driven by deep fluids. Zhou et al., 2022 analyzed three major foreshocks in this sequence and found that they can be explained by the cascade triggering mechanism, but they also found some evidence of aseismic slip. Similar interpretations were reached based on rupture dimension and stress disturbance analysis of foreshocks (Liu et al., 2022).…”

Coseismic Slip Model of the 2022 Mw 6.7 Luding (Tibet) Earthquake: Pre‐ and Post‐Earthquake Interactions With Surrounding Major Faults

“…∆CFS has been used to assess seismicity rate changes and aftershock distributions (e.g., Toda & Stein, 2022), to infer earthquake interactions (e.g., Ellsworth & Bulut, 2018; Stein et al., 1997; Zhou et al., 2022), and to examine advances or delays in the occurrence of future earthquakes (e.g., Toda & Stein, 2020). To investigate the ∆CFS imparted by the Luding earthquake, we employed the slip distribution of our preferred finite‐fault model (Model–2) and carried out the calculation using the Coulomb 3.3 software (Toda et al., 2011).…”

Construction of Long-term Seismic Catalog with Deep Learning and Characterization of Preseismic Fault Behavior in the Ridgecrest-Coso Region (2008-2019)

“…during early aftershocks period (e.g. Tan et al, 2021;Zhou et al, 2022a), or for creeping faults (e.g. Waldhauser and Ellsworth, 2002;Chen et al, 2020).…”