We obtained the rupture process and slip distribution of the 2022 Mw6.6 Menyuan earthquake by jointly inverting accelerogram data and InSAR measurements. The near-field InSAR measurements provide good constraints on the shallow slip distributions (6 km). The combination of two types of data provided improved constrains on slip distribution of the 2022 Menyuan earthquake. The results from joint inversion of InSAR and accelerogram data reveal a 26-km-long rupture length, which roughly agrees with the mapped length from the optically identified surface rupture trace and the InSAR deformation field. We imaged a major asperity with a dimension of 14 × 6 km at 4 km depth updip of the hypocenter. The maximum slip is estimated to be 3.8 m at 4 km depth. The duration of the 2022 Menyuan earthquake is ~14 s, and 90% of the seismic moment is released in the first 10 s. The total seismic moment is estimated to be 1.31 × 1 × 10¹⁹ N·m, equivalent to a moment magnitude of Mw6.7. Our results highlight that the moderate but shallow rupture during the 2022 Menyuan earthquake could intensify the seismic damage on the surface, confirmed by field investigations.

The catastrophic 2004 Sumatra‐Andaman Mw9.1 earthquake associated with destructive tsunamis has characterized Sumatra as one of the most dangerous convergence zones. Nevertheless, the effects of the thermohydrous state on the strongly coupled megathrust of the incoming plate remain enigmatic. By using a three‐dimensional (3‐D) thermomechanical model to compute the temperature variation and the complicated phase transition process of the water‐bearing descending plate which generates unstable thrust slips, we find that Sumatran earthquakes at varying depths are likely under the control of the inter or intraplate hydrothermal regime, which occurs in or close to the petrological metamorphism transition area. The slab dehydration of the water‐rich mid‐ocean‐ridge basalts (MORB) and the ultramafic rocks in the oceanic lithosphere releases a large amount of fluid to the continental wedge and further facilitates arc magmatism. The fluids are prone to upwelling following the subduction channel along the plate interface and thus contribute to the clustering of earthquakes updip of the dehydration front beneath offshore Sumatra. Brittle failure and dehydration embrittlement at depth, along with the temperature differences caused by variant slab geometry, are conjectured to greatly influence the occurrence of fast and slow earthquakes in Sumatra.

Single-stationed geomagnetic vertical intensity polarization (GVIP) anomalies have demonstrated good predictions of the occurrence of large earthquakes in Japan. Nonetheless, due to the lack of a previously densified geomagnetic network, how the multistationary GVIP anomaly (MGVIPA) corresponds to impending earthquakes remains poorly understood. Based on the newly constructed geomagnetic network from 2014 in Qinghai, China, which is composed of 23 electromagnetic stations, we suggested an MGVIPA method to analyze the correlation with large earthquakes since 2015. The results show that (1) the occurrence of MGVIPA is characterized by clusters in time that continue in a short period; (2) the spatial distribution of MGVIPA usually occurs with high values synchronously at several places over the same period; and (3) the Mw ≥ 6 earthquakes occurred in the regions indicated by MGVIPA within a period ranging from 3 months to 1 year from 2015 to 2021 in Qinghai, China.