【摘要】 信浓川地震带位于日本大地沟北部,地壳运动十分强烈,区内地震主要沿信浓川流域发生,并密集成带,大地构造上处于日本海板块向本州板块俯冲的边界线上。该地震带大多数地震为中强震,且均为浅源地震,地震发生伴随着明显的地下水前兆异常,震中区有强烈的超压热水系的喷溢活动。震中区地下水的温度、电导率以及主要地球化学成分呈线性异常分布,并与地震强弱或地震断裂规模有关,地震断层的规模控制了超压热水系喷溢活动的强度和规模。地震发生与超压热水系喷溢活动有着密切的成生关系,超压热水系喷溢活动使断层发生活动所需应力条件降低,诱发地震发生,同时断层活动为超压热水系向上喷溢提供通道。更多还原

【Abstract】 The Shinanogawa seismic belt,which is developed in the Northern Fossa Magna,Honshu Island,Japan,extends along the Shinano River bounding the Eurasian Plate and the Okhotsk Plate.A geopressured hydrothermal system is widely distributed in the Northern Fossa Magna region.Many destructive earthquakes are related to the activity of this geopressured hydrothermal system in the Shinanogawa seismic belt.The expulsion of geopressured hydrothermal system and rising from depth along an active fault triggered the occurrence of an earthquake and opened the fault as a pathway.The anomalous areas in temperature,electrical conductivity and Cl-concentration of groundwater trend northeast as a linear distribution and convincingly demonstrate the presence of a buried active fault at the epicentral area of the destructive earthquake in the Shinanogawa seismic belt.The distribution of the major axis of the anomalous area in groundwater temperature shows an extremely positive relation with the magnitude of earthquake.It means that the distribution of the anomalous area in groundwater temperature may indicate the scale of earthquake fault.The linearly anomalous areas in groundwater temperature resulting from the percolation of geopressured hydrothermal system and having no historical destructive earthquake are of the predicted areas of future destructive earthquakes.Four potential earthquake areas are proposed and discussed based on the re-examinations of the active faults and seismicity in the Shinanogawa seismic belt.更多还原