【作者】 邱泽华；

【导师】 马瑾；

【作者基本信息】 中国地震局地质研究所 ， 地质学， 2006， 博士

【摘要】 高精度钻孔应变仪是一种理想的地壳形变观测仪器,利用这种观测资料开展研究对推动地震学进步具有重要意义。本研究报告涉及同震应力触发地震、断层活动、地球自由振荡、地震前兆和地震预报等多方面,但是钻孔应力-应变观测是贯穿其中的主线。同震应力触发断层活动正在成为新的研究热点。钻孔应变观测记录的同震应变阶对于研究同震应力触发断层活动具有特殊的价值。如果对当地断层活动有比较清楚的了解,那么就可以根据位错理论用这种资料反演同震的应力触发断层活动。考虑到实际地质构造的复杂性,这样的反演结果可能反映的是当地被触发的断层活动的主要影响或综合效果。对昆仑山口西Ms8.1地震触发北京地区断层活动进行了尝试性反演。同样可以根据位错理论用钻孔应变仪观测资料反演现今断层活动。利用2003-2005年钻孔应变观测资料对北京地区活断层活动的进行了初步尝试性反演。泰安地震台有差应变和体应变两种钻孔应变观测仪器,都观测到2004年12月26日苏门答腊大地震激发的地球自由振荡。体应变仪适合观测地球的球形振荡,而差应变仪可以观测地球的环型振荡。观测记录到环型振荡与球形振荡相互的耦合作用。观测也记录到明显的一些振型的谱线分裂现象。用直接观测到的高质量的环型振荡资料求解了0_T3-0_T22等主要振型的Q值。根据两个方向的剪应变观测数据,更多还原

【Abstract】 High resolusion borehole stress/strainmeters provides an ideal type of instruments for observing modern tectonic deformation in the earth’s crust. This report involves our research works in the fields of coseismic earthquake stress triggering, fault activities, free oscillation of the earth, precursory changes prior to earthquakes and earthquake forecast. However, all the researches are related to the observations using borehole stress/strainmeters.Coseismic stress triggering is becoming a frontier subject of earthquake research. Strain steps recorded by borehole strainmeters are of special values in studies of coseismic stress triggered fault activities. According to the linear dislocation theory, we can apply the strain step data to inverse the coseismicly triggered fault slips based on a well understanding of the local active fault distributions. Taken into account the complexity of geological structure, result of such inversion may reflect a comprehensive influence of triggered activities of all local active faults. An attempt inversion has been carried out for possible triggered activities of some major avtive faults over Beijing area by the Ms8.1 Kunlun earthquake.Modern fault activities can also be inversed with the same method based on the linear dislocation theory and applying the continuos recordings of borehole strainmeters. An attempt inversion has been carried out for possible activities of some major avtive faults over Beijing area during the period from 2003 to 2005.When the great Sumatra-Andaman earthquake earthquake happened on 26 December 2004, two different types of borehole strainmeters, namely TJ-dilatometer and RYR-shear-strainmeter, recorded Earth’s free occilation ecxited by this seismic event. TJ-dilatometer is suitable for recording spheroidal modes of Earth’s free occilation, while RYR-shear-strainmeters particularly fits observing toroidal modes. The strainmeters also observed the coupling of spheroidal and toroidal modes as well as some split modes. Q values for modes of 0T3~0T22 are for the first time calculated with direct stran observations of toroidal modes. Since the RYR-shear-strainmeter records shear strain changes in two perpendicular directions, orientations of toroidal maximum shear strain changes are calculated and found to be stablly normal to the symmetrical axis of Earth’s free occilation. It agrees with theoretical anticipation.Following a study on stress changes prior to the 1976 Tangshan earthquake, we discovered a major fault related to this disarstrous seismic event. The newly revealed great fault is at least 90km and has a coseismic vertical dislocation of 3m at the surface. What is more, it possesses the characteristics of a normal listric fault. The great fault can be divided into two parts. The southwestern part is proved by field investigation, leveling data, aerial photography and geophysical exploration, while更多还原