Improvements in strong‐motion seismographic equipment
Robert E. Gebhardt · Transactions American Geophysical Union · 1936
In 1931 the United States Coast ana Geodetic Survey began an extensive program of investigation of strong seismic motions. The program has been carried on continuously since that time, and as a result of a vast amount of field‐work and the accumulation of records a number of changes have been made for the purpose of improving the performance of the instruments. Other changes have been made necessary because of the more exacting requirements of the staff at the office concerned with the reduction of the records.