Old Seismic bulletins to 1920: A collective heritage from early seismologists

This chapter focuses on collective heritage from early seismologists. Scientists began systematic instrumental observation of earthquakes in the latter part of the 19 th century. Several authors describe the history of the development of an adequate instrumentation for seismology. In the 1880s, scientists in Italy, Japan, and Germany began to record more or less continuously the ground motion with their newly developed seismographs. Because of the limited ability to reproduce the original (analog) paper seismograms, seismologists had to describe their observations in words and numbers. The recording instruments were able to produce seismograms in which one could distinguish between the onsets of all three wave types (i.e., P, S, and surface waves), and a common vocabulary for the description of these records was developed. During the last half of the 19 th century, scientists in many countries began to systematically collect data of macro seismically observed earthquakes and the locations of these events, known only on the basis of such data. In some countries, scientists and/or their governments established special committees or commissions to do this work. The earthquake lists and bulletin data from the early seismic stations not only document the history of seismology but also have intrinsic scientific value. Even today, these old bulletins are needed for event relocation as our technique for earthquake location improves. They are also useful for magnitude analysis to establish a consistent magnitude scale.