On a Mercury Tiltmeter and its Application (Study on Some Phenomena Foretelling the Occurrence of Destructive Earthquakes)

Abstract

This article describes the tilting motion of the ground observed before and after the occurrence of strong earthquakes at the observation stations near the epicenters. The instruments used in observation were the tiltmeter of the horizontal pendulum type and the mercury tiltmeter. A comparison of their instrumental functions is discussed somewhat in detail. In conclusion proof is given to the effect that both instruments may reliably be used in the observation of secular changes of ground-tilt. The characteristic tilting motion of the ground observed in connection with the occurrence of two strong earthquakes has also been fully discussed.