张北—尚义地震区的壳幔构造

通过对河北张家口地区的深地震测深宽角反射／折射剖面资料的研究表明：近东西向的张北—崇礼地壳断裂带与北西西向的张家口—渤海地壳深断裂带在张北６２级地震区交汇。在这里延伸至莫霍面的地壳深断裂带和壳内界面的不连续处是汉诺坝大面积玄武岩溢出的通道。震区中上地壳内的局部速度逆转和下地壳内异常的低速带预示着岩浆活动仍较强烈。张家口—渤海地壳深断裂带近期活动可能是张北地震发生的主要因素

750EhrlichG,J,CheThe Crust mantle Structure in Zhangbei Shangyi Earthquake Area

The seismic data obtained from the wide angle reflection and refraction profile passing through Zhangjiakou area in Hebei Province was interpreted.The results show as follows:the Zhangbei deep crust fault zone is nearly EW trending and the Zhangjiakou Bohai Sea deep crust fault zone is NWW trending that meet in Zhangbei earthquake ( M s=6.2) area where both the deep crust fault zones stretching to Moho and the interior crust discontinuity interfaces from the eruptive pathes for Hannuoba basalt in a large area.The local velocity inversion of middle and upper crust in earthquake area as well as the low velocity anomaly in lower crust imply that magmatic activities are still violent.The recent activities of Zhangjiakou Bohai Sea deep crust fault zone may be the main factors which cause the Zhangbei earthquake.