Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

HISTORICAL SEISMOGRAM FILMING PROJECT:CURRENT STATUSDale P. Glover and Herbert MeyersWorld Data Center-A for Solid Earth GeophysicsNational Oceanic and Atmospheric AdministrationBoulder, CO 80303, USAABSTRACTThe addition of important collections of seismograms from Hongo andAbuyama, Japan; Pasadena and Mt. Hamilton, California; St. Louis,Missouri; and Burlington, Vermont, has brought the number of recordsin the historical seismogram film archive to over a half-million microfilmcopies. Seismograms from the Philippines, the USSR, and several locationsin South America are now being added to the file. Station bulletinsfrom 450 stations have also been filmed as part of this project. This reportdiscusses the current status and future plans and presents an overview ofthe project since its beginning in 1979. By mutual agreement betweenWorld Data Center-A for Solid Earth Geophysics (National GeophysicalData Center) and U.S. Geological Survey (National Earthquake InformationService), the Survey will assume responsibility for the U.S. portionof the Historical Filming Project on October 1, 1985.1. IntroductionHistorical seismograms (pre-1963) are extremely important for determining seismicity,assessing earthquake risks and hazards, and conducting earthquake predictionprograms and other studies where long recording periods are needed. Seismologistshave long been concerned that the old seismograms were being lost ordestroyed, deteriorating, or simply not generally accessible. Consequently, theseconcerns were brought to the attention of the General Assembly of the InternationalAssociation of Seismology and Physics of the Earth’s Interior (IASPEI) in1977, and the following resolution was subsequently passed:“Noting that seismograms recorded at observatories around the world arebasic for research on earthquakes and the structure of the Earth, andthat many of the early seismograms have been lost in war, through naturalhazards and deterioration and, therefore, it is essential that seismogramsof significant earthquakes be systematically collected and preservedby making photographic copies at observatory sites, and be made availablethrough the World Data Centres, IASPEI urges that seismologicalobservatories around the world cooperate with a copying program by providingaccess to historical seismograms to be photographed on-site, andby preparing supporting observatory data to accompany the copies.nFollowing up this resolution, the Commission on Seismological Practice of IASPEIestablished a working group for copying and archiving historical seismograms duringthe 1981 joint IASPEI/UNESCO meeting of experts on historical seismograms inLondon, Ontario.Historical Seismogramsand Earthquakes of the World373