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Data Format

SEED (“Standard for the Exchange of Earthquake Data”) is the international standard format for the exchange of digital seismological data. It was developed by members of the “Federation of Digital Seismographic Networks” (FDSN) primarily for the exchange of unprocessed seismological data between different institutions and agencies. The format is suitable for continuous, event- or station-based waveform data from field stations, observatories, networks or arrays. Although it was primarily developed for data exchange, researchers also use it for other purpuses. Usually, SEED formated files contain the digital time series (waveform) data and meta information such as station and channel ID, sample rate or instrument response. MiniSEED files mainly contain waveform data, “dataless” SEED files only meta data. Extensive information on the format can be found in SEED Reference Manual at the IRIS Web-site (http://www.iris.edu/software/, ->“SEED manual (pdf)”). Many data recorder outpout miniSEED data as does the PR6-24 data recorder (Earth Data) used in the GIPP. Accordingly, most (raw) data in the GIPP Archive are in miniSEED format; the GFZ Seismological Data Archive (GEOFON) ships data in SEED format, real-time data comes in miniSEED format. There are a lot of conversion programs and processing routines for SEED and miniSEED file (see also edltools by Christof Lendl).

Until 2005, a large number of 72A recorder (REFTEK) was used at the GIPP. These instruments record data in a proprietary format which can be converted using PASSCAL software (http://www.passcal.nmt.edu/content/software-resources). Possible output formats of the conversion software is SEG-Y or miniSEED; however, some continuous data have been stored in the raw format.

Instruments of type “Portable Data Acquisistion System” (PDAS-100) by Teledyne/Geotech formed the backbone of the GIPP until 2005. These instruments record data in a proprietary format having a rather simple ASCII header and a data block. Additionally, a number of auxiliary files exist containing State-of-Health, timing quality etc. The format is described in PDAS USER'S GUIDE (TELEDYNE GEOTECH; pdf ). Conversion routines exist for example at ORFEUS (http://www.orfeus-eu.org/). Some older continuous data have been stored in the PDAS format.

The SEG-Y format is developed by the “Society of Exploration Geophysicists” (SEG) as a standard format for exchange and archiviung of geophysical, particularly seismic data. A SEG-Y files contains a sequence of trace data, each formed by a trace header and the data (Barry, K.M.; Cavers, D.A.; Kneale, C.W. (1975): Recommended standards for digital tape formats. Geophysics 40 (2): 344–352). Originally developed for digital archiving on magnetic tape, the SEG-Y format is widely used in seismic exploration and data archiving. Many seismic processing systems read SEG-Y data. Additionally, conversion routines are freely available (e.g., seismic un*x; http://www.cwp.mines.edu/cwpcodes/).

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