Chapter 7. Troubleshooting and help

7.1 Troubleshooting

The installation is connected, but Scream! is not receiving any data.

Choose File → Setup… from the main menu and open the Com Ports tab. Check that the baud rate for the serial port attached to the digitizer is set to 19200, and that all the boxes are checked.
Check that the power supply to the sensor and digitizer is switched on and providing a consistent voltage of 12 – 30 V.
Check all connectors and cabling.

The observed signal contains a lot of noise above 1 Hz (1 s).

You are observing “cultural noise” due to human activity. This can be reduced by choosing a more suitable environment for the sensor.

Move the sensor away from noise sources such as machinery (elevators, air-conditioning units, heating systems, pumps, etc.) and traffic (pedestrian or motorized.)
Mount the sensor below ground level.
Enclose the sensor in an insulated box, to reduce the effect of draughts and temperature fluctuations.

The observed signal contains a lot of noise around 0.2 Hz (5 s).

You are observing natural vibrations in the Earth, known as microseisms. These are an inescapable fact of life in most locations. Microseisms can be caused by local storms, rough surf, or large standing waves in the deep ocean. A large proportion of microseismic vibrations travel along the surface.

To minimise the effect of microseisms, install directly on bedrock if possible, or underground in a seismic vault.

The observed signal drifts significantly over a long period of time.

This drift is most likely due to temperature fluctuations in the sensor, caused by changing conditions through the day.

Isolate the sensor from temperature changes and draughts by enclosing it in an insulated box.
Keep the sensor away from strong sources of light and heat (direct sunlight, light bulbs, etc.)

You should give a newly-installed sensor time to reach thermal equilibrium with its surroundings (at least overnight). If drift persists, keeping a record of the times of day when the drift is most prominent can help you track down its origin.

7.2 Limited warranty

The CMG-EDU system has been thoroughly tested and calibrated before leaving the factory. It should provide years of continuous, problem-free operation.

Güralp Systems guarantee that your CMG-EDU will be free from defects in workmanship and materials for a period of 12 months from the date of purchase (as shown on the purchase invoice). This warranty does not apply in the event of misuse or abuse of the product, or as a result of unauthorized alterations or repairs.

7.3 Contacting Güralp Systems

If you have any questions about any aspect of the installation or operation of the CMG-EDU, you should contact Güralp Systems Technical Support at support@guralp.com or by telephone at +44 (0) 118 981 9056 (2 pm – 5 pm GMT)

You should also contact us if the CMG-EDU requires service, either during or after the warranty period. When you call, be ready to quote the serial number of the instrument. This number is stamped into the side of the sensor base, and can also be found on the label on the top face.

Updates to this manual, as well as other technical information about this and other Güralp Systems products, can be found on our website at http s ://www.guralp.com/

7.4 Resources for teachers and students

A complete list of available books and resources on seismology is beyond the scope of this manual. However, some useful starting points may be found on the Web. These links are prone to change.

http://www.indiana.edu/~pepp/ – The Princeton Earth Physics Project, now completed and being run from Indiana University, continues to maintain a web site with extensive information for teachers interested in bringing earth science to the high school classroom.

http s ://www.seismosoc.org/education/education.html – The Seismological Society of America maintains a good bibliography of material useful to teachers and students of seismology.