| 摘要 |
<p>PURPOSE:To simply execute detection of an earthquake. CONSTITUTION:A vibration sensor is provided in a gas meter for measuring the flow rate of a city gas and an output of the vibration sensor is given to a level discriminating means through a low-pass filter 42 filtering a frequency component of about 10Hz or below, so as to discriminate a seismic wave. When the occurrence of an earthquake is discriminated thereby, supply of the city gas is shut off by closing a shut-off valve provided in the gas meter, while the output of the vibration sensor is stored in a seismic wave memory. The state of the earthquake can be known by reading out the content of storage of the seismic wave memory, and also detection of the seismic center or the like can be executed easily, since this gas meter is provided at a large number of places.</p> |
