engleski

Instrumentation for terrestial measurements of geodynamics and the main sources of disturbance

Geodetic measurement of the Earth's strain is determined from measurements between several points on stabilised benchmarks in special networks. The final goal based on such measurements is the description of the deformation of the whole surface. Unlike for other purposes, instruments for geodynamical research are in fixed connection with the rocks. The rock mounts are a part of these instruments, so for proper data interpretation, special care and analyses of site behaviour in time are necessary. Several disturbing influences such as temperature, ocean loading effects, Earth tides, water-table and humidity changes, air pressure and other factors influence the stability of the mounts. An analysis of these influences for proper data interpretation is necessary in order to separate movements of tectonic, seismic and other origins. The changes in position, which we get from repeated measurements in different epochs, are calculated as differences of co-ordinates, vectors or speed of deformation. To get information about what happens between these epochs, instruments for continuous measurements must be utilized. Mostly these are mechanical or LASER extensometers, fluid or pendulum tiltmeters, and nowadays real-time GPS, or a combination of several such instruments.

Extensometer; tiltmeter; continuated measurements; strain; temperature change; air pressure; water-table; humidity change; Earth tides.

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