Katalin Eszter Gribovszki

Recurring mass movements on the Danube's bank at Dunaszekcső (Hungary) observed by geodetic methods

Abstract. In September 2007 a geodetic network based on GPS measurements, precise levelling and continuous borehole tilt measurements was established for surface displacement monitoring on the high bank of the River Danube at Dunaszekcső where a serious landslide began to develop at that time. The landslide took place on February 12, 2008. After rapid, enormous movements, which resulted in significant subsidence (8–10 m) and lateral displacements (4–5 m) on the high bank at Dunaszekcső and the emergence of a peninsula consisting of clastic material in the Danubes bed, the deformation rates significantly dropped. This observation was explained by the secondary metastable equilibrium of the moving blocks at that time. However, our subsequent geodetic data clearly showed that slow post-event movements (mainly subsidence, 0.5–1.0 cm/month) on both the northern and southern sliding blocks have been occurring for the last two years, which means that the sliding blocks did not reach an equilibrium in the mentioned period. At the same time, measurements on our extended geodetic network in the second half of 2010 referred to a possible southward spread of sliding (southern part of the Vár Hill) in the near future. Later on (spring 2011), field observations were also indicative of the initiation of movements on the southern part of the Vár Hill as predicted by the geodetic measurements. The areal extent of the block becoming unstable closely corresponds with the danger zone assigned by GPS observations.

Recent Achievements of the Neo‐Deterministic Seismic Hazard Assessment in the CEI Region

A review of the recent achievements of the innovative neo‐deterministic approach for seismic hazard assessment through realistic earthquake scenarios has been performed. The procedure provides strong ground motion parameters for the purpose of earthquake engineering, based on the deterministic seismic wave propagation modelling at different scales—regional, national and metropolitan. The main advantage of this neo‐deterministic procedure is the simultaneous treatment of the contribution of the earthquake source and seismic wave propagation media to the strong motion at the target site/region, as required by basic physical principles. The neo‐deterministic seismic microzonation procedure has been successfully applied to numerous metropolitan areas all over the world in the framework of several international projects. In this study some examples focused on CEI region concerning both regional seismic hazard assessment and seismic microzonation of the selected metropolitan areas are shown.