Peak Horizontal-to-Vertical Acceleration Ratio and Local Amplification of Strong Ground Motion

Residuals of the peak horizontal acceleration for site-independent attenuation relations are shown to have weak positive correlation with the average observed peak horizontal/vertical acceleration ratio (q) at the recording site. This ratio systematically increases as the hardness of the soil decreases. Taking the average observed q at the recording station into account reduces the scatter of data slightly in fitting the assumed peak acceleration attenuation law. If the soil classification of the data is available, soil dependence is found to be weaker if the data are corrected for the effect of q prior to regression. This correction reduced the mean value of q = 1.85 for the Dinarides area to q = 1.52, which, on the average, is characteristic of rock sites.     

Importance of the unsaturated zone in landslide reactivation on flysch slopes: observations from Valići Landslide,Croatia

Landslides - Field investigations and back-analyses of (re)activated landslides in the Rje?ina River Valley indicate prolonged intense rainfall and the rise of the groundwater table, often to...     

Source potential and palynofacies of Late Jurassic “Lemeš facies”, Croatia

Laminated limestone and calcareous shale outcrop samples from the Late Jurassic “Leme?” facies (Croatia) were investigated to characterize their organic facies and palynofacies and their hydrocarbon generative potential. The results indicate that the organic rich sediments of “Leme?” facies were deposited within a relatively shallow marine environment at low redox potential, characterized as an oxygen depleted depositional setting with stratified bottom waters of the carbonate platform (Adriatic Carbonate Platform). The organic rich samples contain a high portion of lipid rich amorphous kerogen of algal/phytoplankton origin, enriched by bacterial biomass. Most of the analyzed samples have total organic carbon contents (TOC) greater than 3%, Rock-Eval S2 >20 mg HC/g rock, yielding Hydrogen Index (HI) values ranging from 509–602 mg HC/g TOC. According to these results, the analyzed samples have very good to excellent oil generative potential. Relatively high sulfur content suggests that the kerogen is best described as Type II-S. Biomarker maturity parameters, as well as the fluorescence of the isolated kerogen, show that the organic matter is at early to peak oil thermal maturity. The observed level of thermal maturity indicates that these samples were once buried to depths of ～5.5–5.8 km before being uplifted in the late Tertiary. The surface outcrops of the “Leme?” facies suggest that these strata have significant source potential and are the likely source of oil in the Croatian External Dinarides.     

The 1667 Dubrovnik earthquake–some new insights

The year 2017 marks the 350th anniversary of the great 6 April 1667 Dubrovnik earthquake that caused extensive damage in a wide area around this old Dalmatian town (today in Croatia). This article presents the effects of the 1667 earthquake and examines the first few weeks following the catastrophe. Macroseismic data are reanalysed, for the first time available data are collected of the damage on the territory of Bosnia and Herzegovina (the territory which was in the 17th century under the Ottoman reign) and a new map of macroseismic intensities is presented. This map is in good agreement with the macroseismic field modelled using the SAF (Strong Attenuation at Fault Zones) model. We highlight some problems in the collection of macroseismic information, which are mainly a consequence of the complex political situation in the areas affected by the earthquake. The 1667 earthquake heavily impacted Dubrovnik and the Dalmatian coast. This event is thought to be the biggest one in the history of Dalmatia and practically defines seismic hazard in the coastal area of Croatia. For this reason, the main goals in this article are the improvement of the epicenter location and the determination of the moment magnitude.     

The water on a small karst island: the island of Korčula (Croatia) as an example

The island of Korčula, which has an area of 271.47 km² is located along the north-eastern coast of the Adriatic Sea. Due to the Mediterranean climate, size and karst geology its water resources are very scarce. This paper describes the natural features of the island (air temperature, precipitation, geology, hydrogeology and groundwater) which are important for the water appearance and its distribution in time and space. The water supply of the island has been managed in the following ways: through a pipeline from the mainland, by drawing groundwater and by rain harvesting. Tourism causes high seasonal water needs which are barely met by the existing water supply system. Therefore, present water resource management on the island must be improved. The paper also presents mathematical programming scheme to get optimal costs and benefits of water exploitation on the island. Besides economic aspect, linear programming is applied to social and ecological objectives, as well. This study suggests that island’s water management should be primarily based on wisely using its proper water resources.