EARTHQUAKE DETECTING APPARATUS

摘要

PROBLEM TO BE SOLVED: To obtain an earthquake detecting apparatus which prevents a simple 'shock' from being erroneously judged as an 'earthquake' so as not to be operated erroneously. SOLUTION: The number N1 of ON-OFF signals having the continuation time L0 which is set to be shorter than that in a case in which earthquake waves are judged is measured within a prescribed measuring time t0 from the start of the input of an ON signal. When a prescribed number N0 is reached, a vibration which is applied to an acceleration seismographic apparatus 1 is judged to be a vibration due to a 'shock'. As a result, when a signal processing operation to interrupt the processing judgment of a signal is performed in a prescribed time it is possible to prevent the malfunction of a shutoff valve due to the 'shock'.