SPACE ELECTROMAGNETIC FIELD SENSOR, EARTHQUAKE DISASTER PREVENTIVE JUST-BEFOREHAND ALARM GENERATING DEVICE USING THIS SENSOR, AND METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To effectively observe the forerunning phenomenon preceding an earthquake and judge it as an earthquake forerunning phenomenon from the specificity of an electric signal so as to be able to generate an alarm just before the earthquake relatively with accuracy by using an electronic tube that can generate electrons, as a sensor to observe the electromagnetic field in an earthquake disaster preventive just- beforehand alarm generating device and a method therefore. SOLUTION: The electronic tube 1 is used in the state of being exposed to the electromagnetic field to detect an electric characteristic such as the pattern of electronic beams generated by the electronic tube 1. A signal containing noise influence is measured by an earthquake pendulum sensor, a seismometer 23 or an earth current measuring apparatus 22, and the electric characteristic and the measured value are compared to judge whether this electric characteristic is an earthquake forerunning phenomenon or a noise component. Time to issue an alarm just before the generation of an earthquake is judged on the basis of the signal intensity of the electric characteristic at the time of judging the earthquake forerunning phenomenon.