Preserving Analogue Seismograms of Regional Networks in Northeastern Iberia

Session: Back to the Future: Innovative New Research with Legacy Seismic Data [Poster]
Type: Poster
Date: 4/28/2020
Time: 08:00 AM
Room: Ballroom
Description: 

Catalonia, in the NE of the Iberian Peninsula, has a long tradition on seismic recording. The first seismic station in this region, EBR (Ebro Observatory), was installed in 1904. The second one, FBR (Fabra Observatory, Barcelona), started in 1906. Both stations are still active with modern instrumentation, but both also keep their analog seismograms and a large amount of complementary information.

In the last quarter of the 20th century, the Catalan seismic network, operated by the Institut Cartografic i Geologic de Catalunya (ICGC), was established to monitor the seismicity in the NE Iberian Peninsula. The operation of this regional network began in 1985 and, as it was quite common at the time, short period vertical sensors were used. Most of the seismograms obtained up to the year 2000 were recorded on thermal paper. ICGC currently preserves approximately 40000 record sheets from the period 1985-2000. This kind of support is unstable, and records become whitened after a few years. Thus, although we are dealing with post-WWSSN records, actions to preserve them are urgently needed.

A long-term project aimed at scanning these records has been undertaken in recent years. These seismograms show some specific features that distinguish them from WWSSN or other older records. Namely, the high frequency content of the signal requires to use high density scanning (at least 1200 dpi). As this successful experience can be useful to preserve records of other regional networks, we present here the adopted strategies for scanning, classification and diffusion and preliminary results from their analysis.

In addition, these records are now being used to evaluate background seismicity in the region offshore northeastern Iberia, where an apparent increase in seismicity has been observed in coincidence with extraction of hydrocarbons in the region. This research has been partially supported by Ministerio de Ciencia e Innovación grant no. CGL2017-88864-R.

Presenting Author: Antonio Villasenor

Authors