Digitizing analog seismograms of Iranian seismic stations - preserving records for strong earthquakes in Iran 1960-1990

Abstract

Abstract To preserve the analog records of historical earthquakes which occurred in and around Iran in digital form and to make them available for modern analyses techniques that require waveforms, we decided to scan seismograms of destructive earthquakes that occurred between 1960 and 1990. The seismograms have been recorded in five seismic stations deployed in Tehran, Mashhad, Kermanshah, Tabriz, and Shiraz by the Institute of Geophysics of the University of Tehran (IGUT). The restoration project of the old analog seismograms archived in the IGUT started in 2018. Seismograms were sorted by station and date to create a hardcopy data bank, and then those from large earthquakes with significant damage and casualties, and their larger aftershocks, were chosen to scan. At present, over 600 scanned seismograms from 52 major earthquakes, and their aftershocks larger than MW = 5.0 that occurred in and around Iran and some major and great tele-seismic earthquakes from abroad are available. The current digitization process in IGUT is done manually and is based on waveform vectorization. The provided databank is one of the most important sources of information for researchers in seismology and active tectonics in and around Iran.