中国—欧洲共同体地震科学合作项目“北京西北延庆—怀来盆地地震学研究”进展

为探索强烈地震的前兆，在欧洲共同体的支持下，中国和英国的地震学家共同在北京西北的延庆—怀来盆地建立了一个数字地震台网．延庆—怀来数字地震台网由５个野外台和一个中心台构成。研究工作的重点是探索强烈地震前地震横波分裂现象中的参数变化．１９９５年４月３０日台网建成并投入运作．１９９５年７月下旬．怀来地区发生ＭＬ＝４．０地震及其余震，延庆—怀来数字地震台网很好地记录了这一地震序列。初步的分析表明．这一地震序列表明了怀来县城以南６—８ｋｍ处，怀来盆地南缘下部的断层活动，它与怀来地区地表有明显出露的主要断裂没有明显的直接联系。

Progress of the China-European Communities Seismology Cooperative Project 'Seismological Study of the Yanqing-Huailai Basin,NW of Beijing'

To search for the possible precursor preceeding a large earthquake, the seismologists from United Kingdom and China, under the support of the European Communities, cooperatively installed a digital seismic network in the Yanqing-Huailai Basin, NW of Beijing. This network is consisted by five field stations and one base station. The main purpose of the network is searching for the possible variation in the shear-wave splitting behavior before a large earthquake. The Yanqing-Huailai network started its operation in the end of April 1995. In July 20, an earthquake sequence with the largest event of magnitude Mr=4. 0 occurred in Huailai basin and has been well recorded by the Yanqing-Huailai network. Preliminary analysis of the records shows that this earthquake sequence is an indication of the faulting, which is not evidently and directly related to the main faults with outcrop in the Huailal area, in the south edge of the Huailal Basin, about 6-8 km to the south of the Huailai County.