Development of compact seismograph and seismoscope

摘要

At the down of January 17,1995,a devastating 7.2 magnitude earthquake struck Hyogo Prefecture in the Kinki district,Japan.to prevent secondary disaster,Osaka gas was forced to temporarily stop city gas supply to approximately 860,000 customers.Since then,to make full use of the lessons learned from this experience,we have ben struggling to develop various earthquake-related technologies.We have developed a capacitance acceleeration sensor that is less expensive but no less accurate than the servo acceleration sensor conventionally used as a seismograph.On the basis of this technology,a compact.High-accuracy seismogaph has been developed,which will be installed at vaious points in our service area for fixed-point observation.We have also devleoped a seismoscope kthat immediately closes emergency gas shutoff valves for industrial customers when it senses earthquake otion.Htis paper reports these devleopments,and briefly presents possible future applciations of the capacitance sensor.