Advances in seismological methods for characterizing fault zone structure

Large earthquakes frequently occur along complex fault systems. Understanding seismic rupture and long-term fault evolution requires constraining the geometric and material properties of fault zone structures. We provide a comprehensive overview of recent advancements in seismological methods used to study fault zone structures, including seismic tomography, fault zone seismic wave analysis, and seismicity analysis. Observational conditions limit our current ability to fully characterize fault zones, for example, insufficient imaging resolution to discern small-scale anomalies, incomplete capture of crucial fault zone seismic waves, and limited precision in event location accuracy. Dense seismic arrays can overcome these limitations and enable more detailed investigations of fault zone structures. Moreover, we present new insights into the structure of the Anninghe-Xiaojiang fault zone in the southeastern margin of the Qinghai-Xizang Plateau based on data collected from a dense seismic array. We found that utilizing a dense seismic array can identify small-scale features within fault zones, aiding in the interpretation of fault zone geometry and material properties.