| The "Drum" is a virtual seismograph with
its stylus at the bottom right-hand corner of the image. Roughly every
5 minutes a new drum image is generated and uploaded to our web site.
Consequently the drum shifts to the left every 5 minutes. After 30 minutes the image reappears on the right, one line higher up the screen. It takes 24 hours for the data currently at the bottom right of the image to reach the top left of the screen. Every fourth line is shown in an alternate colour to help with
their counting. This is to stop the current line overwriting too much of the surrounding image. Go here to see our new seismic network in action. |