Making non-digitally-recorded seismograms accessible online for studying earthquakes

Abstract

Instrumental observations of earthquakes using the available technology at different times have been carried out over the past 120 years at either single seismic stations or networks of various sizes, from local to global scales. Before the 1980s, almost all seismograms were recorded on paper or photographic medium. Due to wars or neglects, many of these analog (or non-digitally recorded) seismograms had been lost, or are deteriorating and disappearing in a rapid rate. This article is intended to summarize the authors’ efforts to rescue and preserve seismograms, and to post non-digitally recorded seismograms and related research materials online for free access by anyone, anywhere. We also included some background information about observational seismology and constructions of online archives of old seismograms by others.