OPTICAL SEISMOGRAPH

摘要

PURPOSE: To obtain an optical seismograph in which the maximum vibratory speed value is measured accurately by an optical means upon occurrence of an earthquake. CONSTITUTION: The optical seismograph comprises a slip plate 5 which is displaced to the right and left by a quake, and a light emitting element 8a and a light receiving element 8b arranged on the opposite sides of the slit plate 5. A counter circuit 11 determines a maximum vibratory speed value directly from an intermittent pulse signal being detected per a predetermined time by the light receiving element 8b when the slit plate 5 is displaced by a quake to pass the light intermittently through a slit 5a. The maximum vibratory speed value thus determined is presented on a display 12. When the maximum vibratory speed value is higher than a set value, a stop signal is delivered to the process thus interrupting the process emergently.