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本文研究了永胜1515年8级大震震区的新构造活动,发现控制该区的南北向构造带与之交汇的东西向构造新活动十分强烈。断裂活动是多期的,各期的活动方式也不同,反映的应力场在輓近时期发生过多次变化,而永胜地震则发生在上述两组构造的交汇处。永胜地震在基岩上形成两条东西向裂缝带。它们以力学性质特殊(是主压应力方向与东西向发震构造平行情况下形成的典型张破裂型裂缝)和单条裂缝宽度最大(最宽处在8米以上)而在国内外罕见。作为本区控震构造的南北向金河——永胜——宾川断裂中常被文献提到并被监测的程海压扭性逆断层是一条新活动很弱、感受构造应力作用很轻的断层,而改为加强监测其东西两侧其它几条新活动强烈的断层为宜。
This paper studies the new tectonism of Yongsheng earthquake zone of magnitude 815 in 1515 and finds that there is a strong east-west structural activity that controls the north-south tectonic belt intersected therewith. The fault activity is multi-phase, and the modes of activity are different in each phase. The reflected stress field has changed many times in the recent times, while the Yongsheng earthquake occurred at the junction of the above two structures. Yongsheng Earthquake in the bedrock formed two east-west fracture zone. They are rare at home and abroad because of their special mechanical properties (typical cracked fractures formed when the principal compressive stress direction is parallel to the seismogenic anomaly) and the maximum width of a single crack (up to 8 meters at its widest point). The Chenghai pressure-induced torsional thrust fault, which is often referred to in the literature and monitored during the north-south direction Jinhe-Yongsheng-Binchuan fault, as a seismic control structure in this area, is a new activity that is weak and telling that tectonic stress is very light Instead, it has been suggested that it should be strengthened to monitor several other intense new faults on both east and west sides.