Development of Strong-Motion Observation Network Adaptable to Earthquake Education for Citizens and Students

作为强震观测网，截至1991年2月底，已在东京都市地区的9个地点安装了11台SMAC-B2加速仪。观察点包括两所公立初中、三所私立高中、三所大学和一个社区中心。该观测网在1987年的博索半岛久栗海岸地震和1990年的伊豆大岛附近地震等事件中观测到多次强烈的地面运动。为了方便对观测网记录的模拟强震加速度数据进行数字化处理，研制了一套由个人计算机和扫描数字化仪组成的半自动数据处理系统。处理包括：1)加速度数据的数字化，2)数字化数据的校正，如基线和弧线校正，3)波分析，如RT转换和响应谱分析，4)分析结果的可视化输出。对一组40秒的录音进行数字化处理，然后进行一系列分析，最多需要一到两个小时。与传统的数字化系统相比，模拟加速度图数字化所需的时间要短得多。当在许多地点获得加速度计时，数字化和分析的结果反馈给学校和社区中心，并进行简单的指导。在增加。1)调查中等地震对学校建筑的破坏，2)制定学校疏散标准，3)调查地震动特征与初中地震破坏的关系，4)对教师进行地震减灾讲座。强震观测和上述四种活动对地震教育是有益的。

As a strong motion observation network, eleven SMAC-B2 accelerographs have been installed at nine sites in the Tokyo Metropolitan area upto late February, 1991. The observation sites include two public junior high schools, three private high schools, three universities, and one community center. Several strong ground motions were observed by this observation network on the occasions of such as Kujukuri Coast of Boso Peninsula earthquake of 1987 and Near Izu-Ohshima Island earthquake of 1990.A semi-automatic data processing system consisting of a personal computer and a scanning digitizer has been developed in order to make it easy to digitize analog strong-motion accelerograms that are recorded from the observation network. The processing consists of 1) Digitization of accelerograms, 2) Corrections of the digitized data such as base-line and arc corrections, 3) Wave analyses such as RT conversion and response spectral analyses, and 4) Visual output of the analytical results. The time required for the digitization followed by a series of analyses on a set of 40-second record is about one to two hours at most. The time is much less than that required for digitization of an analog accelerogram by means of conventional digitization systems.When accelerograms are obtained at many sites, the digitized and analyzed results have been fed back to the schools and community center with simple instruction. In additions. 1) Investigation of damage to school buildings in moderate earthquakes, 2) Development of school evacuation criteria, 3) Investigation of relation between ground motion characteristics and earthquake damage to junior high schools, and 4) Lecture to teachers on earthquake disaster mitigation, were also conducted. The strong motion observation and the above four activities have been found to be useful for earthquake education.