Sanja Faivre

Relative Sea-Level Change during the Late Holocene on the Island of Vis (Croatia) - Issa Harbour Archaeological Site

The 2.4 ka shoreline evolution on the Island of Vis has been investigated. It represents a particularly interesting area for this kind of investigation due to the existence of the submerged archaeological remains, the antique port of Issa, as well as to the existence of geomorphological and biological sea-level markers. The actual depths of the different parts of the submerged quay have been mapped and measured with respect to the present mean sea-level, applying corrections for tide and atmospheric pressure values at the time of the surveys. The functional heights related to the sea level at the time of construction have also been taken into account. These data were further compared with predictions derived from a glacio-hydro-isostatic model associated with the Last Glacial cycle. During the investigation of the coast, tidal notches and algal rims were found. They were mapped, measured and correlated with results of the submerged port remains, as well as with other available data along the Croatian coast. Our results demonstrate a 199±25 cm sea-level change during 2.4 ka on the Island of Vis. Taking into account the total relative sea-level change, an average rate of around ~0.83 mm/yr is derived. If the isostatic-eustatic component is separated, a tectonic subsidence rate ranges between 0.17 and 0.3 mm/yr depending on the predicted model used. Compared to the Northern Adriatic area, the Island of Vis shows a much smaller component of tectonic subsidence.

Solar pacing of storm surges, coastal flooding and agricultural losses in the Central Mediterranean

Storm surges, leading to catastrophic coastal flooding, are amongst the most feared natural hazards due to the high population densities and economic importance of littoral areas. Using the Central Mediterranean Sea as a model system, we provide strong evidence for enhanced periods of storminess leading to coastal flooding during the last 4500 years. We show that long-term correlations can be drawn between storminess and solar activity, acting on cycles of around 2200-yr and 230-yr. We also find that phases of increased storms and coastal flooding have impacted upon mid- to late Holocene agricultural activity on the Adriatic coast. Based on the general trend observed during the second half of the 20th century, climate models are predicting a weakening of Mediterranean storminess. By contrast, our new data suggest that a decrease in solar activity will increase and intensify the risk of frequent flooding in coastal areas.

Structural influences on the spatial distribution of dolines, Island of Brač, Croatia

The nearest neighbour analysis has been applied to dolines of the island of Brac which provide lithological, climatological and relative structural homogeneity, which facilitated the interpretation of observations. The results show that the doline spatial distribution is clustered at the scale of the island, tends to cluster at the medium scale and is dominantly random at the scale of the doline. The spatial distribution of the index R is particularly interesting. Approaching the main faults, which here are reversed, doline density decreases as well as the index R, while the central parts of the blocks are characterized with greater doline density and with increasing of R values. Doline distribution on the island of Brac also shows properties of anisotropy. The azimuths of the closest dolines are mostly N-S oriented, which is concordant with the maximum stress direction. Significant variations in the spatial distribution parameters and property of anisotropy confirm that the development of karstic depressions, in a relatively homogeneous environment, is strongly controlled by the fracture system and tectonic conditions.

Geomorphological Traces of the Younger Pleistocene Glaciation in the Central Part of the Velebit Mt.

On the central part of the Velebit Mountain the traces of the Pleistocene glaciation have been found. The domination of the dissected relief, characterized by numerous elevations and depressions, in the conditions of low temperatures and richess of snow precipitation during the Pleistocene were a very good predisposition for glaciation development on the central part of the Velebit Mt.

Recent Landform Evolution in the Dinaric and Pannonian Regions of Croatia

This chapter deals with main geomorphological properties of Croatia. The key elements of the geological predispositions are outlined as well as those of geodynamic evolution which, in conjunction with numerous exogenous processes, result in recent landform development. The main points of all important exogenous processes and landforms are presented: coastal, fluvial and fluvio-denudation, slope, aeolian and polygenetic. The main attention has been paid to karst and fluviokarst which cover almost 44% of the territory (the submerged karst excluded) therefore numerous recent research topics are outlined such as the development of structural geomorphological methods in karst, the research on coastal karst, glaciokarst, karst denudation measurements and cave microclimate. All this made a good basis for a detailed geomorphological regionalisation given in the chapter as well.

The changes in beaches surfaces in the Medići and Mimice area from 1960 till today.

U radu se analiziraju promjene žala u uvalama Rascine, Juto i Kutlesa u posljednjih cetrdeset godina. Razmotreni su osnovni prirodni cimbenici njihova oblikovanja, a osobita pozornost posvecena je antropogenim utjecajima koji su taj prirodni razvoj poremetili te nacinu na koji obalni sustav reagira na antropogene modifikacije. Izgradnja dužobalnih konstrukcija, kao i odlaganje materijala u neposrednoj blizini obale i u more zbog naglog sirenja obližnjih naselja i razvoja turizma, uzrokovali su visak sedimenta u moru koji uzrokuje progradaciju i eroziju pojedinih segmenata žala. Kljucne rijeci: obalna geomorfologija, žalo, antropogeni utjecaji (geomorfologija), omisko primorje, Jadransko more, Hrvatska The Changes in Beaches Surfaces in the Medici and Mimice Area from 1960 till Today The paper deals with the changes in beach surfaces during the last 40 years in the bays of Rascine, Juto and Kutlesa. The main natural factors of their formation have been presented, but the focus of attention has been the anthropogenic influences that have disturbed their natural evolution, and the way in which this coastal system has reacted to anthropogenic modifications. The construction of coastal structures, as well as the uncontrolled disposal of material left after construction in the vicinity of the coast and even in the sea, due to the quick expansion of nearby settlements and tourism development, has provoked a surplus of sediments in the sea, causing progradation and erosion of particular beach segments.

The gully of Potovošća on the island of Krk – The effects of a short-term rainfall event

The rainfall event during the night of 10th–11th September 2007 caused strong erosion in the gully of Potovosca on the Island of Krk. In the main fan, two new gullies and two fans were formed. Those morphological changes have been mapped, measured and explained, across the drainage basin in terms of topography and precipitation intensity. The drainage basin morphology was studied using GIS that allowed comparison of morphological and dynamic relationships within the study area. In order to obtain the relative potential erosion intensity between different points in the basin, as well as to differentiate areas with areal (diffuse) erosion from those with dominant linear erosion, the Stream Power Index (SPI) was calculated. The drainage basin specific properties were further related to the event specific properties, precipitation intensity and hydrologic estimations. The rainfall intensities obtained, allow the calculation of discharge at the gully mouth and the definition of recurrent periods using the rational method. The rainfall-runoff event studied was also influenced by the relatively high Antecedent Precipitation Index (API). This allows explanation of the morphological consequences of the short-term event. Consequently the interrelationship between short-term and long-term events has been discussed. In addition, the physiography of the gully has been recently modified by human interference, which has also influenced the morphological consequences of the aforementioned short-term rainfall event.

The Intensity of Increment and of Subcutaneous Karst Corrosion in the Krka River Valley (Croatia)

Na podrucju doline Krke obavljeno je istraživanje intenziteta korozije metodom standardnih vapnenackih plocica. Plocice su postavljene na ukupno pet lokacija u blizini Knina (Krcic) i Skradina. Na svaku lokaciju postavljene su po tri plocice. Za potrebe istraživanja obavljeno je uzorkovanje tla u koje su plocice položene te nacinjena analiza njegovih fizikalno-kemijskih parametara. Mjerenjem mase tj. izracunom intenziteta prirasta ili korozije uocene su velike razlike između plocica. Na podrucju Krcica izmjeren je prirast cije su maksimalne vrijednosti 0, 7797 µm/god., a kod Skradina izmjerena je korozija cije vrijednosti iznose do maksimalno 0, 2436 µm/god. Razlike u uvjetima zbog kojih je doslo do prirasta, odnosno korozije mogu se povezati s klimatskim uvjetima te fizikalno- kemijskim svojstvima tla, posebno njegovim pH te udjelom CaCO3 i humusa.

Formation and Usage of Landslide Digital Databases: Examples from Various Countries and Croatia - Availability of Landslide Data in the Rijeka Area

U radu se daje pregled formiranja digitalnih baza podataka o klizištima u svijetu i stanja u Hrvatskoj. Kao primjer izabrane su države iznimno ugrožene padinskim procesima i/ili one koje imaju razrađene i dostupne baze klizišta (npr. Japan, Kina i Novi Zeland). Prikazuju se parametri od kojih su pojedine baze načinjene (Italija, Slovenija i Hrvatska) te daje prikaz preporučenih kategorija pri izradi inventara i baza klizišta na svjetskoj razini. Također se iznosi pregled osnovne terminologije, iznimno važne u istraživanju i evaluaciji podložnosti padina klizanju, hazarda i rizika. Dostupnost podataka u Hrvatskoj razmotrena je na primjeru riječkog područja.