鲁西隆起、沂沭断裂带及胶南隆起区域地壳厚度、泊松比分析

Analysis on Crustal Thickness and Poisson's Ratio beneath Area of Luxi Uplift,Yishu Fault and Jiaonan Uplift

利用远震接收函数方法得到鲁西隆起、沂沭断裂带及胶南隆起区域30个宽频带地震台站下方的地壳厚度、泊松比值。结果显示:该区域地壳厚度和泊松比呈现不均一、变化大的特征,其中泰山地区、沂沭断裂带郯城—莒县段及RZH台下方地壳厚度值小、泊松比值高。经分析认为,鲁西隆起地壳厚度薄、泊松比值高的区域与底部地幔物质上涌及热侵蚀作用相关;沂沭断裂带地壳厚度和泊松比具有明显分段的特征,体现在断裂带郯城—莒县段地壳厚度薄、泊松比高;莒县—安丘段与断裂两侧的地壳厚度、泊松比值相近,说明其壳幔相互作用主要体现在郯城—莒县段;胶南隆起地区仅RZH台站下方地壳厚度值低、泊松比值高,结合该区域重力异常梯度带特征,推测大型的北北东向断裂带可能是造成RZH台站下方低地壳厚度值和高泊松比值的原因。

We obtained the crustal thickness and Poisson＇s ratio beneath 30 seismic stations in the area of Luxi Uplift,Yishu Fault and Jiaonan Uplift by tele-seismic receiver function method. The results showed that the heterogeneity of crustal thickness and Poisson＇s ratio was obvious in the study area,and the crustal thickness value was lowand the Poisson＇s ratio was high beneath Taishan area,Tancheng-Juxian section of Yishu Fault and RZH Station.We analyzed the obtained result and found that the area of thin crustal thickness and high Poisson＇s ratio beneath the Luxi Uplift was related with the mantle upwelling and thermal erosion in the bottom of Taishan area. The crustal thickness and Poisson＇s ratio of Yishu Fault had obvious segmentation features,which was the crustal thickness was thin and Poisson＇s ratio was high at Tancheng-Juxian section of Yishu Fault. The value of the crustal thickness and Poisson＇s ratio at Juxian-Anqiu section was closer to that of in both sides of Yishu Fault,which was indicated that the interaction of crust and mantle mainly occurs at the Tancheng-Juxian section. The lowcrustal thickness and high Poisson＇s ratio only exited beneath RZH Station of Jiaonan Uplift area,we induced that it may be caused by the NNE-trending fault combined with the gradient zone of gravity anomaly of Jiaonan Uplift area.