| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect the occurrence of an earthquake from the characteristics of the subterranean rumbling caused by the micro-crushing preceding the fracture of a hypocenter fault by detecting the subterranean rumbling related to the occurrence of the earthquake by means of a microphone buried underground and judging that the occurrence of the earthquake is approaching when the rumbling continues for a prescribed period of time and the sound volume of the rumbling shows a tendency to increase. SOLUTION: A hydrophone array 1 detects a waveform of a low frequency 50-150 Hz. When the low-frequency waveform is detected, whether or not the waveform is continuous for, at least, several seconds to several hours is checked. A discriminating circuit 5 judges whether or not the occurrence of an earthquake is approaching by checking whether or not the sound volume of subterranean rumbling gradually increases. When the discriminated result of the circuit 5 is 'Yes', the damage by an inland earthquake is prevented by actuating an alarm device 8 and sending a signal to a substation 10 through a transmitter 9 to stop the power transmission to feeder lines 11, and so on. Thus, an earthquake, particularly, such an inland earthquake that the S wave arrives immediately after the P wave can be detected by judging the occurrence of the earthquake from the characteristics of the subterranean rumbling which occurs before the P wave arrives.</p> |
