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

Research on the deep structure of active faults in the North Anatolian fault zone, Turkey

土耳其北安纳托利亚断裂带活动断裂深部结构研究

基本信息

批准号：
11694063
负责人：
HONKURA Yoshimori
金额：
$ 5.5万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-11694063/
关键词：
Izmit earthquake Aftershock activity Earthquake fault North Anatolian Fault Geomagnetic field and earth current Seismic dynamo effect Resistivity structure Active fault structure 地震空白域余震比抵

项目摘要

We have established a seismic observation network called IZINET and monitored seismic activity.In this network, the Izmit earthquake of magnitude 7.4 occurred on August 17, 1999 and hence we could determine its hypocenter very accurately. The seismic data set obtained from IZINET is very important and many seismologists over the world have used this data set. We also made temporary observations to investigate the aftershock activity and we found a zone of seismic activity along the earthquake faults which appeared on the Earth's surface. The distribution of aftershocks is inhomogeneous and some clustering activities were found. This aftershock data set is also important and has been used by many seismologists over the world. From several years before the Izmit earthquake, the seismic activity was high in the epicentral area. Finally we pointed out that the focal mechanism and the aftershock distribution can provide some important clues for the next future large earthquake in the vicinity of Istanbul. As for electric and magnetic observations, records before, during and after the Izmit earthquake could be obtained. Careful examination of the records shows that the electric and magnetic fields changed drastically with the seismic waves. We interpreted these changes in terms of the seismic dynamo effect. In order to confirm this hypothesis, we made simultaneous seismio and electromagnetic observations at the same site. The records immediately before the Izmit earthquake are important from the viewpoint of earthquake prediction, but so far we have been unable to detect any anomalous changes in the electric and magnetic fields. We also made resistivity survey along some segments of the active fault and found that high resistivity zones prevail in the vicinity of the fault. We then pointed out that the hypocenter of the Izmit earthquake is just located in the high resistivity zone. Also most aftershocks tend to occur in this high resistivity zone.

1999年8月17日发生的伊兹米特7.4级地震，我们建立了一个名为IZINET的地震观测网，对地震活动进行了监测，因此可以非常准确地确定其震源。IZINET提供的地震数据集非常重要，世界上许多地震学家都使用过该数据集。我们还进行了临时观测，以调查余震活动，我们发现了一个地震活动区，沿着地震断层出现在地球表面。余震的分布不均匀，并发现了一些聚集性活动，这套余震资料也是重要的，已被世界上许多地震学家所使用。从伊兹米特地震前几年开始，震中地区的地震活动就很活跃。最后指出，震源机制和余震分布可以为今后伊斯坦布尔附近大地震的发生提供重要线索。至于电磁观测，可以获得伊兹米特地震之前、期间和之后的记录。对记录的仔细检查表明，电场和磁场随着地震波而急剧变化。我们用地震发电机效应解释了这些变化。为了证实这一假设，我们在同一地点同时进行了地震和电磁观测。伊兹米特地震前的记录从地震预测的角度来看是重要的，但到目前为止，我们还无法检测到电场和磁场的任何异常变化。我们还沿活动断层的沿着部分地段进行了电阻率测量，发现断层附近普遍存在高阻带。指出伊兹米特地震的震源正好位于高阻带。此外，大多数余震往往发生在这个高电阻率区。