权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

Study on Characteristics of Geothermal Seismic Noise by Array Observation

阵列观测研究地热地震噪声特征

基本信息

批准号：
04650581
负责人：
SAITO Tokumi
金额：
$ 1.28万
依托单位：
IWATE UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

Georthermal seismic propagation at the kakkonda geothermal area and the eastern region of Hachimantai was investigated by the tripartite method and frequency-wavenumber analysis respectively. The direction of arrival and the apparent phase velocity for seismic noise from 1 to 10Hz were investigated.The conclusions may be summarized as under.1. No diurnal and secular variations of arrival direction for seismic noise at the kakkonda geothermal area are observed. Arrival quadrants obtained near the steam supply system are changed before and after the closure of wellhead valve of gerthermal prodection wells. Seismic noise in the 3-7Hz is arriving from the direction of geothermal reservoir. Apparent phase velocities for the 1-10Hz seismic noise field show the despersive characteristics and can be explained by the Rayleigh wave dispersion curve. Consequently, it is suggested that seismic noise observed in the Kakkonda geothermal area is the fundamental-mode Rayleigh waves which body waves originating at a reservoir were converted near the surface.2. Sesmic noise at the eastern region of Hachimantai geothermal area had a uniform direction of arrival and was originated from a relatively deep subterranean area. Apparent phase velocities for the 1-10Hz seismic noise field show the despersive characteristics and can be explained by the Rayleigh wave dispersion curve.Further evaluation of the effectiveness of geothermal seismic noise survey is required by accumulation of survey data at an increased number of geothermal areas.

分别采用三重法和频率波数分析方法研究了kakkonda地热区和八幡平东部地区的地热地震传播。对1～10Hz范围内的地震噪声的波达方向和视相速度进行了研究。主要结论如下： 1．在卡孔达地热区没有观察到地震噪声到达方向的日变化和长期变化。热采井井口阀门关闭前后，在供汽系统附近获得的到达象限发生变化。 3-7Hz的地震噪声是从地热库方向传来的。 1-10Hz地震噪声场的视相速度表现出色散特征，可用瑞利波色散曲线来解释。因此，认为Kakkonda地热区观测到的地震噪声是源自水库的体波在地表附近转换而成的基模瑞利波。 2．八幡平地热区东部地区的地震噪声具有统一的到达方向，并且起源于较深的地下区域。 1-10Hz地震噪声场的视相速度表现出色散特征,可以用瑞利波色散曲线来解释。随着地热区调查数据的积累,需要进一步评价地热地震噪声调查的有效性。