Guralp have developed some lower cost alternatives to professional-grade seismographs for use in educational institutions. The are limited in performance and features, but represent good value for the basic purposes of teaching seismology.
The CMG-EDU-T triaxial seismograph is based on the CMG-6TD, but with a response of 30 seconds to 40Hz and maximum sampling rate of 40 samples per second with a 21-bit resolution. It cannot store data locally but includes software for installation on a computer to acquire the data for display and analysis. It includes a GPS for accurate signal timing.
A vertical-channel-only version of this seismograph, the CMG-EDU-V, is also available. Contact us using the form at left if you are interesting in purchasing a seismograph for your school.
An example of educational seismographs in action is the Australian Seismometers in Schools project, which used a higher-spec sensors so that the data could also be useful to the scientific community as well as the students.