Current Effort

To expedite the transcription process, we converted all relevant available data from the online NCEDC event catalogs and the in-house phase data to a flat transcription file format for the years 1978 through 1983. We also acquired a copy of the International Data Center (ISC) CDROM which contains events and associated station data published in the ISC Bulletins from January 1964 through December 1977 (Version 1.2). This ISC data set includes event and station data contributed by Berkeley and the CDROM also contains a algorithm to search the database and extract and translate the ISC coded phase Berkeley data to a readable print format for years 1963 through 1977. This enabled us to start with transcription files that contained approximately half of the data that is on the original reading/analysis sheets for the years 1964 through 1983. The primary data from the original reading/analysis sheets, that was not included in this process, was the Wood-Anderson maximum trace amplitude data that is crucial for the determination of local magnitude.

During the past year six students worked on the process of transcribing the data from the original BSL reading/analysis sheets to computer readable form. They started by checking the transcription of the original reading/analysis sheets and locating the earthquakes from 1983 and they have been working back in time. Since none of the data on the pre-1964 reading/analysis sheets exists in a computer readable form, all data has to be transcribed and consequently it takes more time to transcribe each event. Currently they are currently transcribing reading/analysis sheet data from 1951 and they have processed seading/analysis sheets for over 4400 earthquakes which have occurred in NCC. Also, the pre-1951 reading/analysis sheets data do not contain Wood-Anderson maximum trace amplitude data which is used in the calculation of local magnitude so that the original Wood-Anderson seismograms with have to be retrieved from the archive and and the amplitudes read. This quite labor intensive component of the project is planned for the coming year.

Berkeley Seismological Laboratory
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