Seismicity and Complex Magmatic System of the Wudalianchi Volcanic Field in Northeast China

The Wudalianchi volcanic field (WVF) has the latest unambiguous major eruption in China. However, its magmatic system is still not well‐understood. In this study, we deployed a dense seismic array of 193 short‐period seismographs in the WVF to study its local seismicity and fine 3‐D crustal velocity structure. Our results show that a high‐ Vp/Vs anomaly exists at 7–13 km depths below Weishan accompanied by relatively intense seismicity, which might indicate a magma chamber in the upper‐middle crust. The magma chamber is likely responsible for the most recent eruption of the WVF ∼300 years ago. In addition, a high‐ Vp / Vs anomaly is visible at 3–8 km depths below Yaoquanshan and Wohushan. Taking into account the development of carbonate mineral water near Yaoquanshan, we suggest that this high‐ Vp/Vs anomaly reflects a hydrothermal‐rich zone. The magma chamber below Weishan and the hydrothermal‐rich zone below Yaoquanshan and Wohushan might share the same magma source in the upper mantle.