The crust-mantle velocity structure beneath the Wudalianchi-Erkeshan-Keluo volcanic belt by joint inversion of receiver functions and ambient noise

The Wudalianchi-Erkeshan-Keluo (WEK) volcanic belt is a significant component of intraplate volcanism in Northeast China and is composed of the Wudalianchi, Erkeshan, and Keluo volcanic clusters. Using joint inversion of receiver functions and ambient noise, we construct a high-resolution 3-D S-wave velocity model of the WEK volcanic belt and its adjacent region, taking advantage of a deployed dense seismic array around this volcanic belt. There is a prominent low-velocity anomaly at 8–15 km depth beneath the Wudalianchi volcanic cluster, suggesting the presence of a crustal magma chamber. Low-velocity anomalies are also observed at 30–35 km depth beneath the Erkeshan volcanic cluster and 30–40 km depth beneath the Keluo volcanic cluster, resulting in discontinuous velocity structures at the Moho discontinuity. We further find a distinct low-velocity anomaly in the uppermost mantle beneath the WEK volcanic belt. Combined with previous geophysical and geochemistry studies, we propose a magma system scenario for the WEK volcanic belt. The upwelling molten material from the asthenosphere accumulated in the uppermost mantle and the magma chamber was formed, which provided the same uppermost mantle magma sources for the WEK volcanic belt.