On January 8, 2022, the M_S6.9 earthquake in Menyuan County, Qinghai Province stands as the largest and most destructive seismic event in the region in recent years. The earthquake originated at the junction of the Lenglongling and Tuolaishan faults, an area with complex tectonic structures. It occurred in a zone within a 200 km radius of the epicenter where both population and monitoring stations are sparse. This sparsity meant previous research has largely relied on earthquake catalogs derived from existing stations, leading to a lack of comprehensive and in-depth understanding of the region's fine-grained tectonic features and the intricate mechanisms underlying its seismic activity, thus necessitating further intensive research.

This study compiled high-density monitoring network data within a 200 km radius of the M_S6.9 Menyuan mainshock, spanning 129 days before to 235 days after the main event. Employing deep learning models, it conducted microseismic detection and location analysis to further dissect the earthquake. Using the DiTingPicker deep learning picking model, the study automatically detected seismic events and picked seismic phases from continuous raw seismic data. Subsequent phase association was performed via REAL, followed by absolute and relative location calculations using Hypoinverse and HypoDD, respectively. This process yielded an earthquake catalog with 3 637 entries covering September 1, 2021 to August 31, 2022, detecting twice as many earthquakes as the official monitoring network catalog.

Depth projections of the earthquakes revealed that the Lenglongling and Tuolaishan faults have nearly vertical dips, with most aftershocks occurring at depths of 10−20 km. Analysis of the sequence using the epidemic type aftershock sequence （ETAS） model indicated no distinct foreshocks preceding the Menyuan earthquake. Additionally, the temporal and spatial distribution of b-values within the sequence suggested that the Menyuan area is under heightened stress conditions; stress remains incompletely released on the eastern side of the Lenglongling fault and the western side of the Tuolaishan fault, pointing to a certain potential for future strong earthquakes.