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A gyroscopic seismometer: Measurements during the borrego earthquake

INSTITUTE OF GEOPHYSICS AND PLANETARY PHYSICS UNIVERSITY OF CALIFORNIA,, SAN DIEGO

Abstract

The gyro seismometer, consisting of two counter-rotating pendulous Nordsieck gyroscopes, permits separation of tilts from horizontal motion. Sensitivity is limited by the accuracy with which the gyro orientation can be measured, 1 arcsecond rms in a 0.5 Hz bandwidth. This instrumental noise level is equivalent to ground tilts of 1 arcsecond and ground velocities of 0.1 cm/sec. Peak values in the instrumental pass band (0 to 0.5 Hz) of the tilt and horizontal velocity during the Borrego Mountain, California, earthquake of April 9, 1968, were 1 cm/sec and 10 arcseconds respectively. In La Jolla, 115 km from the epicenter, the static displacement and tilt were less than 1 cm and 0.1 arcsecond (5 x 10^–7 radian).

This article has been cited by other articles:

				H. BRADNER and M. REICHLE Some methods for determining acceleration and tilt by use of pendulums and accelerometers Bulletin of the Seismological Society of America, February 1, 1973; 63(1): 1 - 7. [Abstract] [PDF]