应用接收函数方法研究海南及其邻区地幔转换带结构

利用海南、广东及广西区域台网和国家台网共88个宽频带地震台站记录的2007年8月至2010年3月75个远震事件波形资料,采用接收函数共面元叠加的方法,得到了海南及其邻区上地幔410 km和660 km间断面结构和转换带厚度.结果表明,研究区410 km间断面形态较复杂,局部下沉到447 km,而660 km间断面相对简单,其深度分布在670 km左右.海南岛东北部存在一个直径约200 km的转换带异常薄的区域,其厚度较全球平均值薄25±5 km,相当于转换带中存在约180℃的高温异常,转换带厚度局部偏薄暗示海南地幔柱可能起源于下地幔.

Mantle transition zone structure around Hainan by receiver function analysis

We have obtained the upper mantle 410 km discontinuity and 660-km discontinuity structure and transition zone thickness around Hainan by using receiver function method.The data used in this study was teleseismic waveforms recorded by 88 seismic stations of Hainan,Guangdong and Guangxi Regional Seismic Network and National Seismic Network during August,2007 to March,2010.Our results show that the structure of 410 km discontinuity is complex in this region,it is depressed to 447 km locally.The 660 km discontinuity is simple relatively,with the depth around 670km.Transition zone is thinned anomalously by 25±5km within an area approximately 200km in diameter centered northeast of Hainan island,this anomaly is consistent with an excess temperature of ～180℃.The locally thinned transition zone implies that Hainan plume originates from lower mantle.