板块运动与地震各向异性及应力场的相关性统计分析  

Statistical analysis on the correlation between plate motion and seismic anisotropy as well as stress field

作　　者：孙振添[1,2,3] 魏东平[1,2] 韩鹏[1,2] 刘鎏[1,2] 

机构地区：[1]中国科学院计算地球动力学重点实验室,中国北京100049 [2]中国科学院大学地球科学学院,中国北京100049 [3]北京市地热研究院,中国北京100143

出　　处：《地震学报》2013年第6期785-798,938,共14页Acta Seismologica Sinica

基　　金：国家自然科学基金项目(41174084)资助

摘　　要：利用收集到的各种来源共计7 959组的地震各向异性观测数据和21 750组应力场数据,结合板块绝对运动模型计算给出的各板块的运动规律,分别统计分析了板块运动与地震各向异性及应力场的相关性,并对板块运动对地震各向异性及应力场特征产生的影响进行了分析.统计结果表明,阿拉伯、加勒比、胡安德富卡、北美、纳兹卡、太平洋和南美板块上地震各向异性与板块运动均具有较好的相关性,而非洲、南极洲、澳大利亚、欧亚、印度和菲律宾板块上二者的相关性则相对较差.讨论分析发现,板块运动拖动软流圈流动、橄榄岩晶格优选方位、化石各向异性和地幔流动或岩石圈流动等因素均在一定程度上控制并影响着地震各向异性与板块运动的一致性.而板块基底拖曳力、洋脊推力、浮力作用和碰撞及俯冲作用等多种因素共同制约了板块运动与应力场的相关性,使得非洲、可可斯、欧亚、胡安德富卡、北美、纳兹卡、菲律宾和南美板块上二者的相关性较好,其它板块上其相关性则较差.对于俯冲带地区,由于俯冲机制的复杂性和软流圈、岩石圈地幔流动方向的不确定性,其板块运动与地震各向异性及应力场的相关性图像表现复杂,需要结合具体的俯冲带构造进行近一步研究.With the 7959 observation seismic data and 21 750 stress data which have been collected from various sources, and combined the characteristics of each plate＇s absolute motion, this paper statistically analyzed the correlation be- tween plate motion and seismic anisotropy as well as stress field, and studied how the plate motion affects characteristic of seismic anisotropy and stress field. The statistical results indicate that a quite positive correlation between plate motion and seismic anisotropy exists in the Arabian, Caribbean, Juan de Fuca, North American, Nazca, Pacific and South American plates, whereas the corre- lation in plates of African, Antarctic, Australian, Eurasian, Indian and Philip pine is relatively poor. Discussion and analysis shows that, whole the block mo- tion dragging asthenospheric flow, lattice preferred orientation of olivinite, fos- sil anisotropy and mantle flow or lithosphere flow control or affect the consis- tency between seismic anisotropy and the plate motion to a certain extent. Vari- ous factors such as plate basal drag force, ridges thrust, buoyancy, collision and subduction constrain the relation between plate motion and stress field in a combined action, resulting in a good correlation in African, Cocos, Eurasian, Juan de Fuca, North American, Nazca, Philippine and South American plates, and a poor correlation in other plates. For the subduction zone areas, the image of correlativity between plate motion and seismic anisotropy as well as stress field is intricate due to the complexity of the subduction mechanism and the non- directional flow of asthenosphere, lithospheric mantle, and it needs further research in combination with the specific subduction zone structure.

关 键 词：地震各向异性 应力场 板块运动 相关性 统计分析 

分 类 号：P315.727[天文地球—地震学]