MONITORING OF GEODYNAMIC ACTIVITY IN THE WEST BOHEMIA SEISMOACTIVE REGION BETWEEN 1993-1996

The western part of the Bohemian Massif is characterized by repeated e arthquake swarm occurrence, juvenile carbon dioxide waters, mineral sp rings, mofettes, Quaternary volcanics etc. To study the geodynamic act ivity of the region, repeated geodetic measurements of recent crustal movements, repeated gravity measurements and continuous recording of g roundwater level have supplemented the seismological investigations si nce the fall of 1993. The December 4/5, 1993 weak earthquake swarm, th e strongest seismic sequence between 1993-96, remarkably coincided wit h the absolute minimum of the groundwater level and a maximum of gravi ty. Repeated gravimetric measurements confirmed the existence of tempo ral variations of gravity, characterized by a certain correlation with the local tectonic setting. The results of GPS did not prove any disp lacement > 5 mm/a in horizontal component. Precise levelling indicated small negative changes in elevation at several points of measurements . (C) 1998 Elsevier Science Ltd. All rights reserved.