Guralp Systems Limited
Section Index: 7.1 Troubleshooting 7.2 Limited warranty 7.3 Contacting Güralp Systems 7.4 Resources for teachers and students

Chapter 7. Troubleshooting and help

7.1 Troubleshooting

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

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.

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.

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.

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 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

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. – 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. Seismological Society of America maintains a good bibliography of material useful to teachers and students of seismology.