Development and application of water-tube tiltmeter for monitoring geodynamical processes of wide-scale with nanorad resolution
The prototype of a one-end 5.5 m long interferometric water level tilt meter (iWT) operated at the Conrad observatory (COBS) Austria since Aug. 2014 has shown its capability to record tilts of both the physical- and the potential surfaces of the Earth at nanoradian resolution. Starting from high frequency seismic events through tidal and hydrology-induced deformations up to secular deformations, various signals generated by geodynamical phenomena have been already observed by this instrument (see kepujsag.ggki.hu). Based on the observations both the technological improvement of the system and its application is planned in the framework of this proposal.
The main technological improvement includes:
1-The upgrade of the of opto-mechanical construction of the Fizeau-type laser interferometer to make its adjustment quick, easy and optimal. It is essential to obtain sub-nanoradian resolution.
2-The development of a two-end system operated in differential observation mode to eliminate such systematic effects like that caused by e.g. the thermal volume change of the water/steel tube.
3-The development of a biaxial system oriented in N-S and E-W directions to get the full instantaneous tilt vector.
The main goal of the application of the improved system is to link COBS and the Sopronbánfalva Geodynamical Obs. (SOPGO) for the coordinated local monitoring of tectonic events along both sides of the Mur-Mürz active tectonic zone.
These stations could be the core of a regional network extending from the Mediterranean Sea to the Fennoscandian shield to investigate even the change of the flattening of the Earth caused by e.g. global mass redistribution of climate change origin.