In SEISAN one can plot or extract continous data from either a standard SEISAN database or from a BUD or a SeiscomP archive.
Continous data in a BUD or SeiscomP archive
SEISAN reading BUD and SeisComp archives
We have implemented archive reading in SEISAN. The reading routines using Chad Trabant software have been implemented by Ruben Luis. Reading continuous data:
This works just like reading SEISAN continuous data, except there are no S-files, only the archive files. All the same functions are available:
Plotting, zooming and extracting segments and registering events.
Read archive data as an event from eev:
A reference to a segment is made in the s-file and it is treated as if it was a file. When a keyword for archive (ARC) is found, the reading is directed to the archive instead of to a file. The archive reference is e.g.
ARC STAT COM NT LO YYYY MMDD HHMM SS DUR ARC ROSA BHZ PM 2010 1011 0100 00 14400 6where ARC indicate archive, STAT is station code, COM is component, LO is location code YYYY MMDD HHMM SS is start time and DUR is duration in secs.
The archive is defined in SEISAN.DEF,
where each channel is given by
text string: SSSSSCCCNNLL, where SSSSS is the station,
CCC is the component, NN the network and LL the location.
These lines can be generated with program sample_read_wav, which will make a list of all channels in a given set of files (it thus requres to have one of several single files with the channels needed).
The directory of the archive is given by
ARC_ARCHIVE, see e.g.:
ARC_CHAN PMOZ BHZPM ARC_CHAN PMOZ BHNPM ARC_CHAN PMOZ BHEPM ARC_CHAN SFJD LHZIU10 ARC_CHAN SFJD LHNIU10 ARC_CHAN SFJD LHEIU10 ARC_ARCHIVE /uibsan/home/s2000/BUDARC ARC_DURATION 10000.0 ARC_START_TIME 5000.0 ARC_TYPE 1.0 ARC_BY_DEFAULT 0.0where each channel is defined as well as the location of the archive. The specification is the same for both BUD and SeisComp archives. ONLY one archive type can be used at the same time and the archive type, ARC_TYPE is given in SEISAN.DEF.
ARC_VIRTUAL_NETWORK _NO BER HHZNS00 ARC_VIRTUAL_NETWORK _NO BER HHNNS00 ARC_VIRTUAL_NETWORK _NO BER HHENS00The virtual network name has to start with a '_' to make them visible as such in the station selection.
Continous data in a SEISAN database
In SEISAN continuous data has no special format. Continuous data is simply ordinary waveform files that follow each other in time. In order to treat the data as continuous, the data can be put into a SEISAN continuous data base. Such a data base is made as follows:
If e.g. data is to be stored from 3 different stations (three componet files), create 3 databases under WAV and REA with the name of the stations (program MAKEREA). If the continuous data consist of 20-minute files, this would mean about 2200 files pr month, which is a reasonable number. It is now possible for some programs (MULPLT, WAVETOOL) to get access to any or all of the traces in the continuous data base and plot and extract data. If the continuous data is archived from a real-time system it is best to have one database per station as it will at times be necessary to backfill gaps as data may not have arrived in real-time.
Note that waveform files in a SEISAN continuous structure must contain the year and month which is used to located the corresponding year-month structure. The default start of the file names accepted are:
ccmm ccyy-mm ccyymm
where cc is century, yy is year and mm is month. If year and month are placed diffenrently in the file name, their location must tbe specified in SEISAN.DEF, parmeter CONT_YEAR_MONTH_POSTION_FILE.
It is also possible to store the data without having a database for each station:
The waveform files in a continuous data base can have different formats for different stations and one S-file can refer to more than one waveform file, provided they start at about the same time and have the same duration.
A simpler way to use smaller quantities of continuous data is to make a list of these files with DIRF and an application program can then use that list to work with the data. Currently two programs have special options for this kind of continuous data. The MULPLT program will plot data from several files as if it was one file in one continues trace the RESAMP program will resample the data from several files and put it into one output file.