JOINT STUDY ON SEISMIC MICROZONATION IN GRANADA BASIN,SPAIN

这一联合研究项目的主要目的是为在地震期间地震地面运动将被强烈放大的沉积平原和盆地中的地震微区划提供一种实用的方法。然后根据地震运动观测、地震调查和对格拉纳达盆地及其邻近地区既有建筑结构的动力特性进行了全面的地震危险性评估。1997年作为该项目的最后一年，我们做了以下研究项目1.西班牙队在格拉纳达盆地安装了一个强震台网。在西班牙团队和日本团队的合作下，对格拉纳达盆地的浅部结构进行了地震调查，包括微震测量。在西班牙队和日本队的合作下，对建筑结构进行了自振周期和阻尼系数的测量。对1993年和1994年两次破坏性地震的地震烈度分布进行了密集调查。目前正在编制格拉纳达盆地的地震风险图，其中包括对未来地震减灾的若干意见和建议。1997年11月，举行了题为《城市地区地震微区划和风险评估》的西班牙-日本联合研究第三次研讨会，以讨论和总结该项目。1998年3月，我们将在日本开设第四次(最后一次)研讨会，以结束该项目，并与广大观众讨论相关的研究课题。

The principal purpose of this joint research project is to present a practical methodology for seimic microzonation in sedimentary plains and basins, where seismic ground motions will be strongly amplified during earthquakes. Then total assessment of seismic risk is being made based on seismic motion observations, seismic surveys and evaluation of dynamic characteristics of existing building structures in the Granada basin and its vicinity. In 1997 as the final year of this project, we made the following research items.1. The Spanish team installed a strong motion network in the Granada basin.2. Seismic surveys for shallower structure in the Granada basin including microtremor measurements were made with the cooperation between the Spanish team and the Japanese team.3. The measurements of natural period and damping coefficient for building structures were carried out also with the cooperation between the Spanish team and the Japanese team.4. Seismic intensity distribution for the 1993 and 1994 damage earthquakes were densely surveyed.5. Seismic risk mapping for the Granada basin is being prepared including several comments and proposals for the fufure earthquake disaster mitigation.In November 1997, the third workshop on Spanish-Japanese Joint Research titled Seismic Microzoning and Risk Assessment in Urban Area was held to discuss and summarize the project. In March 1998, we will open the fourth (the final) workshop in Japan to conclude the project and also to discuss the related research subjects with general audience.