安徽及周边地区岩石圈有效弹性厚度研究

摘要

基于EIGEN-6C4重力异常和ETOPO1地形数据,采用基于fan小波的相关性分析方法计算安徽及周边地区较高分辨率的各向同性岩石圈有效弹性厚度Te (effective elastic thickness),结合区域地质构造和地球动力学背景进行讨论.结果表明,研究区Te处于5～75 km之间,大别造山带和下扬子地区为Te低值区,郯庐断裂两侧Te值相对较低,河淮盆地和苏北盆地Te值较高,Te分布反映了区域特定地质构造特征和地球动力学背景;地震活动主要分布在10～50 km Te值范围内,集中在Te低值区和Te值陡变带,表明相关区域岩石圈抵抗形变能力较弱,易于发生地震.%The Te map of Anhui and surrounding regions is calculated from EIGEN-6C4 gravity anomalies and ETOPO1 data using the isotropic fan wavelet method.The tectonic structure and geodynamic features of this area are discussed according to the Te map.The results indicate that the Te of Anhui and its surrounding regions varies from 5 to 75 km.The Te values of the Dabie orogenic belt and lower Yangtze region are low,as are the Te values along Tan-Lu fault.High Te values appear at Hehuai basin and Subei basin.The Te distribution mainly reflects the particular characteristics of tectonic structure and geodynamic features of corresponding areas.Most of the seismic activities located in regions with Tc values vary from 10 to 50 km;the spatial distribution of earthquakes indicates that earthquakes tend to occur in regions with low Te or steep Te gradients,further indicating that lithospheres of regions with low Te or steep Tc gradients show higher seismicity rateand are not strong enough to resist deformation.