ウイーヘルト地震計と等価な地震観測装置

Abstract

Wiechert seismograph was designed by Professor Wiechert in the early this century. Vertical and two horizontal components were installed in 1930 at Abuyama Seismological Observatory, Kyoto University. We observed many earthquakes by this seismograph for the period over the half century.The instruments are, however, old and decrepit nowadays.The observation system equivalent to the wiechert seismograph was developed. New system is constructed from servo-type seismoneter, analogue electric circuits and recording systems. The servo-type seismometer responses to the ground velocity for wide frequency range. The ground displacement, resonant frequency, damping ratio equal to those of the wiechert seismograph are obtained by the analogue computing circuits which solve a second linear differential equation.Two kind recording systems are adopted, namely digital and pen-writing system.The former is trigger-compile system and the latter is drum-type one which can record continuously four days per one sheet.