Italian National Research Council  Research Institute on Seismic Risk

Mariano Maistrello                 open file 96-01;           Milan,   February 1996

An unified procedure for the digital acquisition and processing
of the old Italian DSS analog seismic magnetic recordings.
  HP 9000/310, Op.Sys.:HP BASIC,rel.4.3; sw: MENU_HP©  ver. 7.'95

Summary :

The final version of an unified procedure for the A/D conversion and first processing of the old analog seismic signals used at our Research Institute on Seismic Risk (IRRS) of the Italian National Research Council (CNR) of Milan is presented. This new release (7.95) consists of a synthesis of the old procedures by which we made a great collection of thousands of seismic signals recorded during the old DSS surveys over the whole Italy, starting by early ‘70. The main updating are emphasized. The environment is the old but still reliable BASIC-HP, and all the software is written in such language, using the two machines HP-9000/310 series of our Group, and runs under BASIC 4.3 (or grater) operating system.
Riassunto :
Viene presentata la versione finale unificata della procedura per la conversione A/D di segnali sismici analogoci e prima elaborazione digitale in uso presso il nostro Istituto di ricerca sul Rischio Sismico (IRRS) del Consiglio Nazionale delle Ricerche (CNR) di Milano. Questa nuova versione della procedura rappresenta una sintesi delle esperienze di questi anni, che hanno permesso di recuperare migliaia di vecchi segnali sismici registrati nelle campagne di sismica a rifrazione profonda sul suolo Nazionale, a partire dai primi anni ‘70. In questa versione (7.95) sono evidenziate le caratteristiche innovative rispetto alle precedenti versioni. Molti moduli della procedura sono stati completamente riscritti in linguaggio BASIC-HP apportando le modifiche necessarie per una gestione più efficiente e guidata. La piattaforma su cui gira l’intero pacchetto si basa sulla macchina HP-9000 serie 310, con sistema operativo BASIC, release 4.3 o superiori.

     The MENU_HP procedure is functionally composed by 4 main steps:

  1. Input-File creation: in this preliminary phase, the Operator is requested to manually enter all the available land data, with all the information regarding the shot point and the 'station' (space, time and instrumental info); at the end a special file (DAXY...)  is created , which will be the reference file for the Header information to be written in each multiplexed binary seismogram-file (DAT....);
  2. DIGIT and Time-Code processing : this is the 'heart' of the procedure: the analog seismograms are properly checked (using analog device like scope, freq. meter, etc), extracted from the magnetic tapes and digitized (by means of the HP-98640A 8-channels A/D interface card, externally drived and syncronized with the Pilot reference signal (PLL-controlled) and soon processed (the Time-Code signal, first, then the wave-form and if necessary the Header alpha-numeric information). Furthermore a final check is made, in order to verify the correctness of the time and amplitude information;
  3. Single seismogram-files creation : in  this step, the Time-Code signal is erased, and the digital seismogram is reduced in window, using a specific criterium connected to the Shot-Station Distance and the P and S-wave velocities, and saved in a 'reduced' ASCII file;
  4. File transfer : the final step lies in transfering the reduced-files to the local PC, using a common communication talking-package; this PC is linked to the Internet network, so the well organized seismic data can be finally easily transferred via FTP into our local Seismic Database.
The whole procedure is well guided and self-protected
against possible data erasures and/or unauthorized data editings.

The following are the two main pages; using the proper buttons the User can: operate all the necessary steps to acquire the analog signals (at least two channels: one time-signal plus the seismic one),  read and decode the various time-codes, complete and verify the header data, check and/or edit some data-failure (spikes), collect all the organized seismic traces into proper 'profile' and/or 'fan' file, make a first processing (FFT spectral analysis and a raw plotting of a section-FILM with selected data-file), and transfer files to our main archive, to be well organized into the final DSS-ON-LINE data base.

Page 1 of 2 (User 1):

        <f1> : HELP [ Hardware & Software ]
        <f2> : Input-file INXY... [ Example / Create / Edit / List / Print / Conv.BDAT ]
        <f3> : computes AZIMUTH & DISTANCES   [Printer output and DAXY... file creation ]
        <f4> : Output-file DAXY... [ Listing / Printing ]

        <f5> : => go to the next Page 2 (User 2)
        <f6> : STOP / EXIT
        <f7> : DIGIT [ digitization of a 2/4 channels seismic analog signal into a DAT... file ]
        <f8> : HEADERs files DAT... or R_... [ Edit(DAT...) / Listing / Printing ]

Page 2 di 2 (User 2) :

        <f1> : Other Software [ SHOWFILE / TIME / DSEE / A_PCC / FILM ]
        <f2> : DEMULTX [ separation / demultiplexing of channels into reduced files R_... ]
        <f3> : DAT... file [ Save on / Load from  FLOPPY ]
        <f4> : DIARY updating of the digitized surveys

        <f5> : <=  back to previous page 1 (User 1)
        <f6> : STOP / EXIT
        <f7> : DIR of selected VOLUME ( Floppy / system VOL.0 / VOL.1 (DAT.. file) / VOL.2 (Red. file)
        <f8> : FORMAT and/or DELETE the selected VOLUME ( Floppy / VOL.1 / VOL.2 ) :

  Here is a list of the modules created, with their dimension; those signed with 'P' are BASIC Programs, the other are subroutines.

 The following are the main specs of the A to D card used by our HP-9000/310 Basic Computer for this procedure: the Hewlett-Packard mod. 98640A. Purchased in 1987, this 12-bits card (+ sign bit) is still working very well, and in respect of the specifications written by the Company. Excellent!



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[ 5 ] Maistrello M.; "Digitizzazione dei segnali (sismici) e processing successivo"; open File report CNR - IRRS, 1993
[ 6 ] Maistrello M., Scarascia S., Ye S., Hirn A.; "EGT 1986 Central Segment - Compilation of seismic Data (additional Profiles and Fans) in Northern Apennines, Po Plain, Western and Southern Alps"; open File report CNR-IRRS, 1991
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[ 8 ] Microstuf, Inc.; "CROSSTALK XVI: the 16-bit communication program"; rel. 3.61 - 1986
[ 9 ] Sherbaum F., Johnson J.; "User manual for PITSA"; 1990


I thank the Collegues Mr G.Boniolo and A.Corsi for their useful collaboration and suggestions during the different steps of the work and tests.