The Wilmot survey type strong-motion earthquake recorder (The U.S.C.G.S. Seismoscope) part II

The results of laboratory tests on the adjustment, accuracy, and performance of the seismoscope are given. The effects of stylus pressure, record plate curvature, method of adjustment, and other factors on the damping characteristics of the pendulum were experimentally investigated, and the results are embodied in recommendations for a standard procedure for the field installation and checking of the instrument. The accuracies of such basic instrument parameters as period and tilt sensitivity were established, and the overall level of duplicability of results attained by typical instruments was determined. A comparison of the behavior of similar instruments made by different manufacturers was made. The results of field tests involving the measurement of actual ground motions caused by blasts and earthquakes are given. The location of some 50 of the Wilmot seismoscopes in a network covering the Los Angeles area is given, together with available information as to local geology and soil conditions at the seismoscope sites