Japan-China Cooperative Research for Earthquake Prediction

目前日中在地震预报方面的合作研究是继1987年开始、1989年结束的第一个三年合作项目之后，在以下四个领域进行的。本次合作研究时间仅为一年，主要成果总结如下：(1)唐山地区地震微区划在中国唐山地区的微震测量表明，微震反映了唐山地震中识别的地面运动特征。因此，微震测量是地震微区划的一种简单实用的工具。(2)不同类型水管倾斜仪的比较研究国家地震局地震研究所使用国产fsq型水管倾斜仪对中国地壳的连续运动进行监测。东京大学地震研究所最近开发了一种名为“ERI '90型”的新型水管倾斜仪。为了进一步证明资料的可靠性，在中国中部宜昌站用这两种倾斜仪对地壳瓦片进行了对比研究。到目前为止，结果令人鼓舞，未来将继续进行联合测量。(3)渭河盆地地震活动与地壳结构3年来对渭河盆地微震活动的连续观测表明，除了铜川观测点的微震活动略高于邻近地区外，该盆地的地震活动非常低，S-P间隔小于1 ~几秒。盆地的微震测量结果表明，中国和日本的地壳结构是不同的。(4)上西地震带的活动构造与新构造上西地震带在16 ~ 17世纪地震上非常活跃。野外对活动构造和第四纪构造的协同研究表明，尽管区内常发生走滑型地震，但区内正断层发育良好。上西地堑的大通火山群在10万多年前开始活动，该地区的应力场可能在最近发生了变化。少

Present Japan-China cooperative research on earthquake prediction was undertaken in four areas as listed below, following the first three-year cooperative project that began in 1987 and ended in 1989. The cooperative research was for one year only, and the major outcomes are summarized below.(1) Seismic Microzoning in the Tanshang AreaMicrotremor measurements in the Tangashan district of district of P. R. China have revealed that the microtremors reflect the characteristics of the ground motion recognized during the Tangshan earthquake. The microtremor measurements are thus a simple and practical tool for seismic microzonation.(2) Comparative Study by Watertube Tiltmeter of Different TypesInstitute of Seismology, State Seismological Bureau, is in charge of continuous crustal movements in P. R. China, using FSQ-type watertube tiltmeter developed in China. Earthquake Research Institute, University of Tokyo recently developed a now watertube tiltmeter called "ERI '90 type". In order to im … More prove the reliability of data, comparative study of crustal tile by using these two types of tiltmeters has been carried out at Yichang station located in central part of China. The results are encouraging so far, and the joint measurements will be continued in the future.(3) Seismicity and Crustal Structures in Weihe BasinContinuous observations of microseismicity in the Weiha Basin over the period of three years, have revealed that the seismic activity in the basin is very low except for the observational point in Tongchuan where the microseismic activity, with S-P interval less than 1 to several seconds, is slightly higher than in the neighbouring areas. The microtremor measurements in the Basin suggest that the crustal structures in China and Japan are different.(4) Active Structures and Neotectonics in Shang Xi Seismic ZoneShang Xi Seismic Zone was seismologically very active in the 16th to 17th centuries. Cooperative field work on the active structures and Quaternary structures has revealed that a sequence of normal faults are developed well in the field, despite that strike-slip type earthquakes occur in the area. The Daton volcanic group in Shang Xi Grabens ceised its activity more than 100,000 years ago, and the stress field in the area might have changed fairly recently. Less