分散于大陆板块内部的小规模火山和岩浆活动的成因机制是研究板块理论和地球动力学的关键问题之一。目前，对板内火山的成因尚未达成一致认识。长白山火山是研究板内火山成因机制的典型区域。本课题以长白山火山为研究对象，围绕局部地幔物质上涌的机制这一核心问题，通过对地震波穿过低速体后出现的波形畸变现象的拟合，反演长白山下方低速体的高分辨率结构，进一步研究“板内火山下方的地幔物质上涌过程是局限于上地幔还是起源于地幔过渡带甚或下地幔”，从而构建长白山火山的成因机制模型。本课题将运用谱元法程序（SPECFEM3D）在高性能大型计算机阵列上模拟高频（0.5Hz）远震地震波在复杂三维介质中的传播，通过拟合大型密集宽频带地震台阵（NECESSArray）观测到的地震波形畸变现象，反演长白山地幔的三维高分辨率结构。

The bulk of observed magmatism on Earth occurs on plate boundaries and is well explained by plate tectonics. However, the origin of diverse small-scale intraplate volcanic activity is difficult to explain in the context of plate tectonics and has remained controversial. The Changbaishan volcanic complex is approximately 1300 km away from the Japan Trench and is a typical place to study the origin of such intraplate magmatism. This project will focus on the origin and mechanism of mantle upwelling beneath the Changbaishan volcanoes. Forward modeling and inversion of high-frequency teleseismic waveforms will be used to reveal fine structures of the slow anomaly beneath Changbaishan. Waveform distortions caused by the slow anomaly will give finer constraints on seismic structures than conventional traveltime tomography and can lead us to understand where the mantle upwelling come from, the upper mantle, the mantle transition zone or the lower mantle. In this project, a spectral element method (SPECFEM3D) will be adopted to perform the forward modeling and adjoint inversion of high frequency (0.5Hz) waveforms across a large dense seismic array (NECESSArray) in Northeast China by using a large high performance computer cluster. The results of this project are expected to lay constraints on relationship of mantle upwelling and stagnant slabs in the mantle transition zone, and help to build a new geodynamic model for intraplate volcanism.