最大有效力矩准则约束下的广西罗阳山地震、地质与地貌效应

使用重新调查后的1936年灵山63/4级地震的烈度资料,结合罗阳山西北麓和南麓的河流地貌与地质构造考察,参考该地区裂变径迹年代学资料,探讨了罗阳山地区的地质力学环境。重新调查后的极震区等烈度区有北北西和北东2个优势方向区域,这2个区域围绕北北西向的泗州断层和北东向的寨圩断层展布。在构造与地貌调查中发现:罗阳山山体有地貌隆升表现,并得到了裂变径迹证据支持;罗阳山西北麓山前冲沟具右旋活动表现;泗州断层内部破裂面的倾向以南西向为优势方向,并具顺时针旋转和高倾角特征。地震分布显示:寨圩断层和泗州断层交汇部位的东南侧有小地震密集展布现象。经分析后认为,以上构造地貌现象是最大有效力矩准则约束下的地震、地质和地貌效应。

GEOMORPHOLOGICAL FEATURES IN LUOYANGSHAN AREA, GUANGXI ZHUANG AUTONOMOUS REGION AND ITS RELATIONS WITH THE MAXIMUM EFFECTIVE MOMENT CRITERION

In this paper,data about the intensity distribution in the meizoseismal area of Lingshan M=63/4 earthquake,geological structure,geomorphologic investigation and fission track dating were used to discuss the geomechanical environment in Lingshan Hill area.In the meizoseismal area,a T-shape IX＋zone coupled NE Zhaixu Fault and NNW Sizhou Fault.Researches on tectonics and geomorphology showed uplifting of Luoyangshan Hill.The data of fission track dating supported this geomorphologic phenomenon.A new channel in front of Luoyangshan Hill（Gaodong） appeared in the west of the old channel.Distribution of earthquakes showed that a lot of low magnitude earthquakes concentratedly occurred in the southeast of the cross zone of NE Zhaixu and NNW Sizhou faults.All above were controlled by the Maximum Effective Moment Criterion（MEMC）.