Formation Mechanism of Volcanic Belt and New Understanding of Seismic Activity in Northern Hainan Island, China

Abstract

AbstractThe distribution map of global volcanoes shows that three parallel volcanic belts exist in southern Asia. Among them, the middle volcanic belt involves the Northern Hainan Island. We simulate a double subduction model for investigating the formation mechanism of this volcanic belt by using finite element method. The result shows that double subduction might induce double convection and the upwelling of the upper mantle in between, resulting in the formation of NS‐trending intraplate volcanic belt. Moreover, the accurate location of earthquakes from 2000 to 2006 in Northern Hainan Island indicates that most of the earthquake foci in this region are concentrated in a vertical plane, which might be attributed to magmatic intrusion along vertical dyke or expansion fault. The “dog‐bone” pattern well explains the distribution feature of earthquakes in the northern Hainan Island and the surface vertical deformation of the region that is characterized by uplift in the east and subsidence in the west.