8:30 AM - 8:45 AM
[S05-1-01] On guidelines for preservation and usage of analog seismogram archives
invited
Seismology is an observational science, and seismograms routinely exhibit features that are not yet fully understood.
The time-scale of earthquake occurrence requires examination of ground motions recorded over periods far longer than the three decades now available from the era of digital recording. Most underground nuclear test explosions, and almost all atmospheric nuclear tests, took place during the era of analog recording.
Different countries have taken different approaches to making analog seismograms usable in the modern era. There is much to be learned from shared experience. Can we develop consensus on those analog records that must be rescued, and preserved with metadata, for use by future generations? We can hope to learn from advanced programs of data rescue, applying successful methods to unexplored archives.
About fifteen different United States institutions hold substantial archives of analog seismograms, containing information needed by future generations of researchers. Consensus is needed on selection of datasets that should be converted from analog to digital form, for use by younger generations who often expect data centers to provide digital data from well-characterized instruments. Such selection of suitable datasets, can be informed by circulating practical information on the level of effort needed—information that has been acquired by countries that have engaged in this type of work for decades.
The Lamont Geological Observatory of Columbia University deployed a sparse global network of Press-Ewing instruments in the mid-1950s, preceding the WWSSN deployment by several years. I give examples of analog recordings of large atmospheric explosions that exhibit phenomena not recorded via digital media---including, from the 1950s: high-altitude explosions above the Pacific recorded teleseismically; and multi-megaton explosions in the atmosphere recorded on vertical component seismometers via the effect of density variations in the air.
The time-scale of earthquake occurrence requires examination of ground motions recorded over periods far longer than the three decades now available from the era of digital recording. Most underground nuclear test explosions, and almost all atmospheric nuclear tests, took place during the era of analog recording.
Different countries have taken different approaches to making analog seismograms usable in the modern era. There is much to be learned from shared experience. Can we develop consensus on those analog records that must be rescued, and preserved with metadata, for use by future generations? We can hope to learn from advanced programs of data rescue, applying successful methods to unexplored archives.
About fifteen different United States institutions hold substantial archives of analog seismograms, containing information needed by future generations of researchers. Consensus is needed on selection of datasets that should be converted from analog to digital form, for use by younger generations who often expect data centers to provide digital data from well-characterized instruments. Such selection of suitable datasets, can be informed by circulating practical information on the level of effort needed—information that has been acquired by countries that have engaged in this type of work for decades.
The Lamont Geological Observatory of Columbia University deployed a sparse global network of Press-Ewing instruments in the mid-1950s, preceding the WWSSN deployment by several years. I give examples of analog recordings of large atmospheric explosions that exhibit phenomena not recorded via digital media---including, from the 1950s: high-altitude explosions above the Pacific recorded teleseismically; and multi-megaton explosions in the atmosphere recorded on vertical component seismometers via the effect of density variations in the air.