IMPACT OF GEOGRAPHIC CHARACTERISTICS ON EARTHQUAKE EFFECTS IN THE POSOČJE

Abstract

In the last few decades, Slovenia was fortunately not struck by any natural disasters which, by their extent of damage or number of victims, could be ranked among major world disasters. This, however, does not apply for natural disasters within Slovene ethnic boundaries. The 1976 earthquake in the Friuli region of Italy claimed more than one thousand lives. This earthquake also caused severe damage in Slovenia, but fortunately no lives were lost. Nevertheless, Slovenia should seriously consider the probability of the recurrence of a major earthquake in our country that could claim a great many lives, such as the 1511 earthquake (Lapajne, 1988). The relief of the upper Posočje region is one of the most diversified in Slovenia. Due to the nearness of the sea, the altitude changes abruptly over small distances, ranging from 200 to more than 2000 m above sea level. The upper Soča River valley does not have any larger or more extensive plains or basins that are so typical of other parts of Slovenia. The valley broadens only near Bovec, Kobarid and Tolmin, where the flatland extends towards the branching Nadiža River valley. Evidently, the present morphological structure is to a considerable extent the result of tectonic activity and other particularities of the region. There is no doubt that the upper Posočje region is one of Slovenia’s most earthquake-prone areas. In an interval of only 22 years, this part of Slovenia was struck by two series of catastrophic earthquake shocks – in 1976 and 1998. These two seismic events were different both by their nature and effects. The first earthquake in 1976 was much stronger than the 1998 earthquake, but its epicenter was located approximately 25 km away on the other side of the border, in neighbouring Italy. As in the case of the 1976 earthquake, a field investigation of seismic activity in the upper Posočje region was initiated in 1998. The consequences of natural disasters are always multi-layered, which is why different teams of experts participated in this investigation. The project entitled »Effects of the 14 April 1998 Earthquake in the Bovec Region on Buildings, Persons and the Environment« was coordinated by the Slovene Institute of Civil Engineering, and performed in cooperation with the Anton Melik Geographic Institute at the Scientific Research Centre of the Slovene Academy of Arts and Sciences, and the Psychology Department of the Faculty of Arts and Sciences of the University of Ljubljana. The contribution presents the geographic dimensions of the consequences of the last two major earthquakes in the Posočje region.