パソコンによる日本列島地震観測網の収録と波形処理

Abstract

A continuous storing system of seismic waves recorded at short-period seismic network was developed by using personal computers (PC) and magneto-optical (MO) disk. The system consists of two personal computers, one for A/D conversion and the other for data storing, with a 12 bits A/D converter. Clock corrections are performed with respect to a signal delivered every minute from an outer clock. The data storage is performed on an magneto-optical (MO) disk of 640 M bytes linked to the PC. The acquisition programs are written in assembly language on MS-DOS. A special format is used for the acquisition as storing 3 data points on 2 bytes and this permits the acuisition of 30 channels at a rate of 20 samples

sec. One side of an MO disk can continuously store the data for 4 days.Within 4 days the MO disks reversed to the other side and it can store data again for 4 days. A MO disk thus typically contains one week data. Data recorded at a network on a MO disk are mailed to the Data Center of "J-array", a study group for "the Central Core of the Earth", located at the Research Center for Earthquake Prediction, Kyoto University. The present system is in operation at 9 regional networks as of May, 1992. Data analysis programs also prepared in assembly language for a quick review of the recorded data, such as arranging seismograms with epicentral distance, filtration and time corrections, stacking sum of seismograms and so on.