Research on absolute gravity variations in geodynamic laboratory in Książ in the period of 2007- 2011

Abstract

In 2006 a gravimetric pavilion was installed inside the Geodynamic Laboratory (LG) in Książ. The pavilion was equipped with two pillars intended to serve relative and absolute gravimetric measurements. Installation of measurement platform for absolute gravity measurements inside gravimetric pavilion of LG made it possible to perform four sessions of absolute gravity measurements: two of them in 2007 (June 10-12 and Nov. 21-22), one in 2008 (Apr. 21-22) and one in 2011 (June 19-21). In 2007 the absolute measurements were performed using two FG5 ballistic gravimeters. In April 2007 the measurements were performed by Dr Makinen from Geodetic Institute of Finnish Academy of Science with application of FG5 No. 221 absolute gravimeter. In June 2007 and in the years 2008 and 2011 such gravimetric measurements were performed by the team from Department of Geodesy and Astronomical Geodesy of Warsaw University of Technology using FG5 No. 230 absolute gravimeter. Elaboration of observation sessions from both gravimeters was performed in the Department of Higher Geodesy following the procedures used in constituting of uniform gravimetric system of geodynamic polygons reference. This constituting of gravimetric system comprised inter alia application of identical models of lithospheric tides (global model by Wenzel, 1997) and ocean tides (Schwiderski, 1980) (reduction of absolute measurements with tidal signals). Observations performed during summer of 2007, autumn of 2007, and spring of 2008 and 2011 indicated existence of small changes of absolute gravity of the order of 1 Gal. Maxima of accelerations appear in the spring period, and minima in the autumn period. This effect is connected with the influence of global hydrological factors the annual amplitude of which is ca 1,5 Gal and achieve extreme values in the spring-autumn interval. Very small value of observed amplitude of gravity changes in the period of extreme variability suggests that the observed gravity changes in LG are caused only by global phenomenon. This proves high degree of „independence” of gravimetric measurement base in LG from the local environmental factors such as ground water level variations, ground humidity, impact of snow cover, etc. At this moment the instrumental environment of absolute measurements obtains particular value, especially in the case of the tiltmeters and relative the gravimeter Lacoste& Romberg (LR-648). The relative gravity measurements as performed simultaneously with absolute gravity measurements enable us to determine the local tidal ephemeredes which makes it possible to replace the global tidal modal with ocean tidal model with the more realistic, locally determined tidal parameters (the local tidal ephemeredes).

Fractal discrete fracture network modeling of radon gas concentration in underground tunnels under Książ Castle in Poland

“…The site comprises a system of underground tunnels beneath the cour d'honneur of Książ Castle, divided into two parts: the non-tourist section and the tourist route. The Geodynamic Laboratory (GL) of the Space Research Centre of the Polish Academy of Sciences (SRC PAS) is situated in the non-tourist section, which was established in the mid-1970s (Kaczorowski 1999;Kaczorowski et al 2012). This laboratory facilitates research on non-tidal processes, including kinematic effects in the rock massif (Kaczorowski and Wojewoda 2011;Kasza 2014).…”

The assessment of lining structure impact on radon behaviour inside selected underground workings under the cour d’honneur of Książ castle

“…The work was done by prisoners from the concentration camp Gross-Rosen [58][59][60][61][62]. Since the 1970s, the research site has been a part of an underground geodynamic laboratory [65][66][67][68][69][70] and as such it is an underground workplace where occupational activity, as defined by Atomic law [63] recently amended in compliance with the EU regulations [64], is conducted in radiation exposure conditions [1,2,63,64].…”

Gravity field modelling and gravimetry

“…This proves high degree of "independence" of gravimetric measurements in LG from local environmental factors such as ground water level variations, ground humidity, impact of snow cover, etc. Relative gravity measurements performed with LaCoste&Romberg G-648 gravimeter simultaneously with absolute gravity measurements are used to improve local tidal model in Ksiaz (Kaczorowski et al, 2012).…”