Tidal tilt measurements at the Schiltach Geophysical Laboratory

Tidal tilt results from six different sites within the Schiltach mine observatory involving four different types of instruments are reported. A comparison with theoretical tide parameters should discriminate between instrumental or regional tectonic influences and strain induced tilts from local inhomogeneities. The site topography and geology is recalled and the tide station described. The different instruments (vertical pendulum, horizontal pendulum and liquid drop types), mounting, measuring procedure, and data processing are treated. The results comprise tidal measurements of the main tides M2, O1, K1, and S2, tilt and residual ellipses, amplitude spectra, and coupling coefficients. The mean errors of the vertical pendulum instruments are found to be persistently smaller. Strong significant scatter of 01 and M2 tidal parameters is interpreted as strain induced tilting stemming from local heterogeneities.