Basic Usage of the SeismoGraf Software

Before starting up SeismoGraf make sure GPSgraf is running, has aquired satellites, and is locked on to absolute time. If not, go to "Basic Use of GPSgraf" section.

If this is the very first time that SeismoGraf is used, make sure that the A-to-D board PCI slot number and the slot number entered in SeismoGraf software "instramentParams" are the same. See "Customizing the SeismoGraf Application" section.

• The SeismoGraf program should reside in the "xxxx_Station" directory. If not place it there. Double-click on SeismoGraf. SeismoGraf is now running.
   
• SeismoGraf has 3 windows. One of them is just the "About" window, click anywhere within this window to bring it to the front, then click on the "OK" button to close it. Of the two remaining windows, one is the seismogram graphics window; seismograms will be displayed here, but initially it just has the SeismoGraf logo. The other window is the Clock and Messages window. It displays the hour:min:sec, and it will display the same time as the Macintosh clock. For the most part, it will not be necessary to watch the cryptic "messages" that scroll through the Message window. However, it is useful to watch them for the initial start-up of the A-to-D board. When first starting up, SeismoGraf does NOT start the A-to-D board at that instant, it waits until the next minute. When it starts the A-to-D board, it displays the error codes in the message window, the two error codes are "DAQ..." and "Lab...", and the integer that follows the cryptic IDs should be "0", which means no errors.
   
• At the next minute SeismoGraf will start the A-to-D board, but the graphics window will still show the SeismoGraf logo. The A-to-D board has a buffer that stores the digitized seismogram, SeismoGraf reads from that buffer every minute, on the minute. Thus, it will take one more minute. Then SeismoGraf gets the last minute of data and it does several tasks:
   
  1. It writes into the current seismogram files the "s" file within the "Data" directory within the "xxxx_Station" directory, and the "a" file within the "Data" directory in the "Web Pages" directory.
  2. It also writes into the DayView files, both within the "xxxx_Station" and "Web Pages" directories.
  3. Finally, it updates the graphics window to include the seismogram from the last minute.
      
• When the seismogram is plotted in the graphics window it will probably just be a straight horizontal line. This is because the default plot gain for SeismoGraf (and SeismoView) is x1. To see the ground motions, the plot gain needs to be increased:
   
  
  1. Go to the SeismoGraf menu bar.
  2. Click and hold on "Plot Control."
  3. Go down to the "Plot Gain" submenus.
  4. Still holding down the mouse button, highlight the "All" submenu.
  5. Still holding down the mouse button, now select the plot gain... "x64" is probably a good first choice.
      

  Changing the plot gain in this window does not change anything about the seismogram that is being written into the files, so change it as often as desired. The key feature to look for is that at the highest gain setting, the seismogram should look "seismological"; in particular, the microseism ground noise (typical period is about 6 seconds) should almost always be seen.

  To get the current minute and 20 second time marks in the graphics window, use the window resize tab at the bottom-right of the graphics window to resize the window.

  If the seismogram is a flat horizontal line at the highest gain setting, then there is a problem. Check all the seismometer's hardware connections, and A-to-D board slot parameter setting in the SeismoGraf software.

  Click to see an example of a typical seismological signal from the S-102 and SeismoGraf system. This seismogram is from the OhioSeis station SSUO, at Shawnee State University. The dominant ground noise is the "6-sec microseisms".

• As SeismoGraf records and displays seismograms it is a good idea, especially the very first time SeismoGraf is used, to make sure that data is flowing into the files. Double-click on the "Data" directory (it is within the "xxxx_station" directory). A directory for today's date, e.g., "2003.02.28", or whatever today might be, should be seen. Double-click on that folder icon. Inside should be at least one "s" file. The file name identifies what is in the file, it lists:
   
  1. station name,
  2. component, "Z" for vertical ground motion,
  3. instrument type, "IP" for broad-band,
  4. and the time range of the enclosed seismogram, as: "Year.Month.Day.Hour."
      

  Thus, each file contains the seismogram for one hour (hours are 0 through 23). SeismoGraf automatically creates these day folders and files within the "Data" directory. Once it is started, SeismoGraf can run unattended for days, weeks, or months at a time (though not recommended).

• Go back to the "xxxx_station" directory, and double-click on the "DayView" directory, you should see a "DayView" file for today's date -- recall that there is just one file for each day.
   
• Finally, check on the duplicate seismogram and DayView files that are created within the "Data" and "DayView" directories within "Web Pages" folder. After navigating through the file hierarchy to get there, same file names as seen in the xxxx_Station directory should be found, EXCEPT that they start with "a" -- that is these files are ASCII files, i.e. they are written in plain text, and hence can be viewed with any text editor or word processor.

  When double-clicking on one of these files, the Macintosh will try to open the file with the built-in text editor ("Simple Text"). The "a" seismogram file size is approximately 150 Kilobytes (K) for an entire hour, hence "SimpleTex" will probably say that it can not open such a large text file. This is not a problem, because (1) word processor programs can easily open files of this size, and even better (2) SeismoView can read in and display these "a" files, though the mirror-image "s" files in the "Data" directory within "xxxx_station" are opened much faster by SeismoView.