Szabolcs Ákos Fábián

Surface changes on a landslide affected high bluff in Dunaszekcső (Hungary)

This article presents results from the survey conducted on Dunaszekcső loess bluff after the last major rotational sliding event in 2008. The study area is a region of 25×30 m located on loess bluff close to the recent scarp. The relative elevation change of the surface was surveyed in 2.5×5 m grid network in relation to a marked base point. The survey was conducted using simple equipment such as analogue theodolite and leveller with regular time interval during a year and control measurements were taken after six months.It was assumed that measurements to the nearest cm are sufficient to recognize vertical displacements of the surface. The study focused on identifying the pattern of general vertical movements for the study area by the relative movements of individual points. Our results show significant cm scale vertical displacements. Most of the grid points have a slow decreasing tendency, but close to the scarp a more significant displacement was found. The main character of the spatial pattern is subsidence, which is more definitive on southern part of the study area than the northern part. Our observations correlate with the broader geomorphological characteristics of loess bluffs along the Danube.

Dunaszekcső Castle Hill: Landslides Along the Danubian Loess Bluff

Mass movements along the Danube banks are quite frequent events in the landform evolution of Hungary. A particular combination of geological, geomorphological, climatic and hydrological factors induces failures on loess bluffs. Clay layers of buried paleosols, steep slopes of loess bluff, water level fluctuations of the Danube and extreme precipitation events control the occurrence of landslides. The lateral erosion of the Danube has destroyed the edge of the Mezőfold loess plain and Tolna–Baranya Hills since the river began to shift westwards from its former course across the Danube–Tisza Interfluve ca 40 ka ago. Remnants of the Ancient Roman fortresses along the eastern frontier of the Empire indicate the time scale of bank retreat: ca 2–2.5 m per 100 years. The recorded dimensions of historical landslides reach 20–30 m in width and 100–1,000 m in length along the Danube. The largest landslide of the past decade occurred at Dunaszekcső Castle Hill in 2008 and in 2011 it endangered the village again. The lack of precise archeological reconstruction of the groundplan of Castellum Lugio encumbers to estimate the rate of bluff retreat. According to the latest studies Danubian floods dominantly control recent movements. The continuous monitoring of the landslide provides valuable information on the dynamics of such movements.

Reconstruction of fl ash fl ood event in a small catchment: Nagykónyi, Hungary

Zusammenfassung. In unserer Studie versuchen wir die am 13.05.2002 in Nagykonyi (Ungarn) in den Abendstunden entstandene Sturzfl ut (engl. „fl ash fl ood“) zu rekonstruieren und zu modellieren. Zirka zwischen 18:30 und 19:15, innerhalb von 45 Minuten ergoss sich ein heftiger Regenfall auf das geforschte Gebiet. Wegen den Lokalverhaltnissen stromte eine Uberfl utung in der sich in einem Erosions- und Derasionstal befi ndenden Barsonystrasse. Da dieses Ereignis zu den ersten ahnlichen Katastrophen der letzen 10 Jahre gehorte, wurde leider kaum dokumentiert. Darum konnen die entstandenen Ergebnisse nur unter entsprechenden Schranken richtig gedeutet werden, durfen als Tatsache nicht angenommen werden. Wegen der in dem Klima von Ungarn erscheinenden extremen Wetterlage werden das Erforschen und das Kennenlernen dieser fruher kaum gekannten Erscheinung immer wichtiger. Von der hydrometeorologischen Lage hinaus wird das Entstehen und Schadigung der Sturzfl uten von den lokalen Eigenheiten und Aspekten beeinfl usst. Nach den zur Verfugung stehenden auf dieses Gebiet bezogenen Radaraufnahmen (MRL-5) fi el 21 mm Niederschlag auf das erforschte Einzugsgebiet nach der Lokalzeit am Nachmittag zwischen 18 und 20 Uhr, aber nach der Messung einiger Einwohner hatte es 54 sogar 92 mm sein konnen. Nach unserer Messung mit dem Modell HEC-HMS 3.2. hatte die Gesamtwasserergebigkeit der Wasserfl ut zwischen 2.8 und 7 m

Review on Denudation Levels of the Western Mecsek Mountains (Sw Transdanubia, Hungary)

A denudation level is a well-known and widely used concept to understand landform evolution, which became one of the benchmarks of geomorphology in the last century. But there is still a question: how can we use formerly described denudation levels to identify the main stages of surface development? The literature abounds in methods to measure the absolute age or determine the relative age of denudation levels, but these methods are expensive or cannot be used in the Western Mecsek Mountains due to the lack of correlative sediments. A revision of the established ages and origin of denudation levels based on the recent geomorphic theories is also needed. In this paper we revise the formerly published geomorphic maps as well as local and antiquated terminology on the denudation levels of the Western Mecsek Mountains, using classical geomorphic interpretation supported with GIS. Three denudation levels were mapped and their relative age was determined based on the comparison of their altitudinal relations and the revision of data from previously published papers. These denudation levels, even if reshaped, represent the Early to Late Miocene and Early Pleistocene phases of surface development. Therefore, the review of the relative age of denudation levels helps summarize our knowledge on the surface development in the Western Mecsek Mountains and it can be the base for further geomorphic studies. We expect these data will become a rich source of information to other researchers studying denudation levels of the Carpathians and the Carpathian Basin.