Changning shale gas field

Location of Changning shale gas field. (a) Changning Shale gas Field (CSF) in the southern Sichuan Basin (SCB), China. (b) Hydraulic fracturing (HF) well pads (yellow squares), horizontal well trajectories (black solid lines) and identified fault traces (magenta lines) from Ma et al. (2020). The dashed boxes indicate the coverage of a two-phased nodal array with station locations shown in (c). The cyan triangles represent 10 short-period seismic stations in Tan et al. (2023). The orange dots show the seismicity detected by the dense array between February 28, 2019 and May 8, 2019. Two red stars mark the 2018 M5.7 Xingwen earthquake, 2019 M5.3 Gongxian earthquake, and the 2023 four M4+ earthquakes, respectively. The arrows indicate the maximum horizontal stress oriented at N107°(Li et al., 2023). Top right rose diagram shows fault orientation distribution. (c) Detailed station distributions of the two-phased nodal array.