Automatic digitization and processing of strong motion accelerograms, 1979

This report presents the current data reduction and analysis procedures which are used in routine processing of strong-motion accelerograms at the University of Southern California. It presents recent developments and changes with respect to our first report in 1973 dealing with this subject (Trifunac and Lee, 1973). -- The First part of this report (Part I) describes the new hardware facility for automatic computer digitization of analog film accelerograms. This facility is now completed; it is operational and performs automatic digitization on a routine basis. Since it is capable of digitizing raw data an order of magnitude faster than the semi-automatic hand-controlled digitizers considered in our previous reports (Trifunac and Lee, 1973), for completeness of the system, the entire mini-computer software package for the corresponding data handling and processing has also been developed (Part II). Though the principles of baseline correction, instrument correction and spectral analysis of strong-motion accelerograms remain the same as in Trifunac and Lee (1973), it has been necessary to modify the old programs written for an IBM-type computer, to the form convenient for a mini-computer using disk operating systems.

本报告介绍了南加州大学（University of Southern California）当前用于强震加速度记录（strong-motion accelerograms）常规处理的数据缩减与分析流程，并针对1973年发布的首份相关主题报告（Trifunac与Lee，1973），阐述了近期的研究进展与流程调整。报告第一部分介绍了用于模拟胶片加速度记录（analog film accelerograms）自动计算机数字化（digitization）的全新硬件设施。该设施现已完成部署并投入日常运行，可稳定执行自动数字化作业。相较于此前报告（Trifunac与Lee，1973）中提及的半自动手动操控式数字化装置，其原始数据数字化速度提升了一个数量级。为保障系统完整性，配套的完整小型计算机（mini-computer）数据处理与分析软件包也同步开发完成（第二部分）。尽管强震加速度记录的基线校正、仪器校正及频谱分析原理与Trifunac和Lee（1973）的研究保持一致，但针对IBM型计算机编写的旧有程序已需适配采用磁盘操作系统（disk operating systems）的小型计算机，因此进行了相应的适配修改。