【摘要】 利用中国国家台网60个宽频带地震台站和国际地震中心(ISC)592个台站分别记录的1996—2007和1990—2004的震相报告,从中提取出可供反演使用的远震事件9806个,共12078个高质量的P波初至走时数据,对中国东部地区进行了远震P波层析成像研究。结果显示,在五大连池火山区和大同火山区有明显的低速异常,大同火山源区较深。另外几个明显的低速区分别分布在广东地区、渤海湾地区和长江中下游地区。四川盆地的高速特征和扬子板块的低速特征在纵剖面图像上也较为明显。中国东南部的软流圈中存在大面积的地幔上涌,认为是由板块之间的碰撞俯冲、引起大尺度地幔横向流动造成的,而太平洋板块的作用局限于其俯冲的"远程效应",为大范围的软流圈物质上涌提供了东侧的深部动力条件。更多还原

【Abstract】 A detailed three-dimensional P-wave velocity structure of the crust and the upper mantle beneath eastern China was determined by applying teleseismic tomography to 12078 high-quality P-wave arrival times from 9802 teleseismic events recorded by 652 broadband stations of seismic networks.The tomographic image shows that obvious low P-wave velocity(low-Vp) anomalies exist under Datong volcano,Wudalianchi volcano,Guangdong Province,Bohai Gulf and Yangtze block.Significant high-Vp zone of Sichuan basin and low-Vp zone of Yangtze block are also fairly evident in images of vertical cross-sections of P-wave tomography.The collision-driven,large-scale lateral mantle flow under eastern China may help explain the broad and dispersive mantle upwelling under eastern China.The subduction of Pacific plate is only one of the mantle upwelling causations.更多还原