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Improvement of micro-earthquake monitoring method in large scale landslides in snowy areas

雪区大规模滑坡微震监测方法改进

基本信息

批准号：
07554019
负责人：
OKI Yasue
金额：
$ 10.3万
依托单位：
NIIGATA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07554019/
关键词：
Noise eliminator equipped seismograph Seismic wave selecting program Geopressured hydrothermal system 1995 Northern Niigata Earthquake Buried active fault 微小地震観測雑音除去大規模地すべり消雪井戸水温

项目摘要

Monitoring of seismic activity in snowy area in winter should be done at easily accessible sites close to roads which are always open by snow removing operation. The noise at sites far away from snow removed roade is very quite, however, no body can easily be access seismograph due to thick snow blanket to collect seismic records as well as the maintenance of the equipments. The seismograph have to set at noisy site, which is close to roade always opened by snow removing operation. This is a motivation to develop a noise eliminator equipped seismograph.Two same pickups are linearly arranged perpendicular to a noisy road. As the absorption of wave amplitude is very large in terms of distance, the difference of wave signals between two pickups is considerably large when the noise source is close to the monitoring sites. Distances from real earthquake are almost same for two pickups installed at monitoring site. Based on the above principle, a seismograph named as STR-110 equipped with two pickups and a micro computer circuit working for nose selector is developed. Waves recorded by the seismograph are treated by a computer program named MCD to select seismic waves from noises. MCD program is developed by the Fourier analysis of seismic waves and noise waves.Using newly developed STR-110 with MCD program, 74 evens consist of 24 earthquakes, 48 noises and 4 unclassified are analyzed. 45 noises are separated, which correspond to 92 % of total noises. Further experiments are required to improve suitable parameters to eliminate man made noise during micro earthquake monitoring.This research project also involves monitoring of seismic activity in relation to geopressured hydrothermal system. The 1995 Northern Niigata Earthquake with M 6.0 provide suitable example for a case study of geopressured hydrothermal system and seismic activity. Geopressured thermal water is discharging up to surface along fractured zones developed along active faults.

冬季雪区地震活动的监测应在靠近道路的容易到达的地点进行，这些道路通过除雪作业始终是开放的。远离除雪道路的地点噪音很小，但由于厚厚的雪毯，任何人都无法轻易接近地震仪来收集地震记录以及设备的维护。地震仪必须设置在噪音较大的场地，靠近经常因除雪作业而开放的道路。这是一个动机，开发一个噪音消除器配备地震仪。两个相同的传感器线性排列垂直于嘈杂的道路。由于距离对波幅的吸收非常大，当噪声源靠近监测点时，两个拾取器之间的波信号差异相当大。安装在监测点的两个传感器与真实的地震的距离几乎相同。根据上述原理，研制了STR-110型地震仪，该仪器配有两个传感器和一个用于机头选择的微机电路。地震仪记录的地震波经MCD程序处理后，从噪声中筛选出地震波。MCD程序是根据地震波和噪声波的傅立叶分析而编制的，用新研制的STR-110程序对74个事件进行了分析，其中包括24个地震、48个噪声和4个未分类事件。共分离出45种噪声，占总噪声的92%.在微地震监测过程中，需要进一步的实验来改进合适的参数以消除人为噪声。本研究项目还涉及与超压热液系统有关的地震活动监测。1995年北方新泻6.0级地震为研究超压热液系统与地震活动提供了一个合适的实例。地压热水沿着活动断层发育的裂隙带向上排至地表。