Debris flows are one of the natural disasters that can occur in the alpine environment, cause large economic damage, and endanger human lives. This study presents an overview of recent research done in relation to the debris flow hazard assessment and conceptual mitigation at the Koro?ka Bela area in Slovenia. This includes fieldwork, lab experiments, modelling, and a conceptual design of hydro-technical measures to reduce the risk. The results indicate that multiple debris flows occurred in the past in the area but a relatively long period of more than 100 years without an extreme event led to urbanization and development of the area. Magnitudes of the most extreme events as the worst-case scenarios were estimated to be in the range between 100,000 and 400,000 m3, using debris flow modelling and geological information from research trenches. Based on the landslide volumes, such events could also potentially occur in the future in extreme conditions. Additionally, torrential floods could mobilize more than 15,000 m3 of material located along the stream network that can be regarded as potentially unstable. The existing check dam system does not have the capacity to capture this material. Thus, a new check dam and three flexible net barriers could help to reduce the risk due to torrential outbursts or debris flows.
During the ascent, emplacement and post-emplacement deformation of igneous rocks, two or more phases of deformation that overprint
each other are often depicted. These overprints, when magnetic minerals are present, are recorded in magnetic fabric. In this
contribution, overprints are studied by means of numerical modeling, following several basic scenarios common to igneous rocks.
Biotite and amphibole that occur often together in igneous rocks are considered as carriers of the anisotropy of magnetic
susceptibility. Modeling shows that (1) a constrictional fabric with a low degree of anisotropy as commonly recorded in magmatic
rocks may result from a deformation overprint and not necessarily from an extensional/transtensional regime, and (2) that
the constrictional AMS fabrics originates from orthogonal superimposition of a deformation event on an AMS fabric inherited
from earlier magma emplacement history. Therefore, the interpretation of a constrictional fabric must be performed with caution.
Numerical modeling may provide a suitable help in strengthening the interpretation of real magnetic fabric data. 相似文献
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. 相似文献
Recurrent climate‐induced mass mortality episodes have been recorded in the Mediterranean Sea over the past 15 years, affecting rocky benthic communities. In this study, we provide for the first time a report on the annual mortality events of benthic sessile invertebrates occurring in the eastern part of the Adriatic Sea. Over the course of 14 consecutive years, we studied the sea temperature gradient to a depth of 40 m and found an abnormal summer warming trend and an increased frequency of above‐average temperatures. Mortality events were recorded in the summers of 10 observed years, in particular in 2009, when the highest mortality rates were recorded. Late in summer 2009, extensive mass mortality of sessile invertebrates was observed in the entire Eastern Adriatic Sea. We performed an analysis of selected target benthic species associated with mass mortality events with inter‐regional differences in hydrological and temperature conditions. We were able to characterize the mortality event by studying five areas covering the northern, central and southern regions of the Eastern Adriatic Sea. The degree of impact on each study area was quantified at 28 sites by estimating the proportion of affected target species. According to the obtained data, the northern sites (Cres area) were the least affected, whereas sites in the Central and Southern Adriatic [Tela??ica and Lastovo Nature Parks, Mljet National Park (NP)] displayed the highest impact. In summer 2009, sea surface temperatures reached values of 28 °C in the Cres area and 30 °C in Mljet NP. These thermal conditions were concomitant with moderate to severe mass mortalities of benthic populations. Mass mortality events reached depths of 45 m in most parts of the affected areas. Amongst studied species, the scleractinian coral and gorgonian populations suffered the most extensive damage during the mass mortality events. 相似文献
A steady-state groundwater flow model of three Quaternary intertill aquifers in the eastern part of Lithuania has been compiled. The distinction of separate modelled layers is based on hydraulic and isotope-hydrochemistry data criteria. 3H data were used to estimate the corrected groundwater age and were coupled with a groundwater-flow-dynamics model of the Quaternary aquifer system along a cross-section flow pathway from the Baltic Upland recharge area in eastern Lithuania towards the discharge area in the lowlands near the city of Kaunas in central Lithuania. The bicarbonate content in groundwater (214–462 mg/l) increases downgradient towards the lowland area. The other major constituents and total dissolved solids (TDS) have a trend analogous to the bicarbonate. The 14C activity of dissolved inorganic carbon (DIC) in the groundwater ranges from 41.4 to 85.7 pMC. With aquifer-system depth, active precipitation of aqueous solution takes place by dissolving minerals of calcite and dolomite and leakage of “old” groundwater from lower aquifers; the process is also traced by lower 14C and 3H activities and by more positive δ18O values in lowland areas. 相似文献
Evaluation of a 45-year data set of primary production (PP), a 30-year data set of phytoplankton biomass, and a 51-year data
set of species composition shows an increase of phytoplankton biomass and abundance in the period from the mid-1980s to the
mid-1990s. Phytoplankton biomass showed bimodal seasonal cycles, with winter and spring maxima, which did not change over
the past 30 years. Diatoms were the most abundant functional group and they prevailed during the colder part of the year while
the dinoflagellate contribution to the phytoplankton community increased in the warmer period from May to August. Diatoms
showed a significant negative correlation with sea surface temperature (SST), while dinoflagellates were positively correlated
with SST. An increase of phytoplankton abundance, particularly dinoflagellate, in the period from the mid-1980s to the mid-1990s
coincided with years characterized by a high North Atlantic Oscillation (NAO) index. Primary production and chlorophyll a concentration in the spring period were negatively correlated with the NAO winter (DJFM) index, probably caused by increased
precipitation associated with a low or negative NAO index. PP in winter during the mixing period was positively related to
the NAO winter index associated with higher temperatures and dry conditions which brought more clear days and increased input
of solar radiation. 相似文献
We present a comprehensive analysis of the dynamics of Veritas family members located in a chaotic strip centeredat 3.174
AU. A total of 600 chaotic members of the family and their clones were integrated for 100 Myr, and the variation of the distance
with respect to the barycenter of the family have been computed forall of them. A simple classification of the prevailing
behaviors hasbeen introduced to help identify typical dynamical patterns and states that could affect an estimate of the upper
bound to the age of the family. We pointed out the importance of the temporary captures in thequasi-stable states, which occur
often enough to affect the statistical analysis of the exits. The results are compatible with the young age (<100 Myr) for
the family of Veritas, but we cannot say precisely how young it really is.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
Palaeo- and rock-magnetic investigations of the St Bertrand’s Spring (Le Ravin de Font de St Bertrand) locality in France were carried out in order to contribute to, and improve, the stratigraphy of the Jurassic-Cretaceous boundary interval. Magnetic susceptibility shows slightly diamagnetic behaviour in the lowermost part of the profile and an increase (paramagnetic) towards its middle and upper parts. Rock-magnetic measurements throughout the section show magnetite as the main magnetic fraction, together with traces of hematite. Additionally, thermal demagnetization indicates the presence of goethite. Our magnetostratigraphy indicates three normal/reversed polarity sequences; possibly encompassing the magnetozones M19r to the M17n. This suggests that the St Bertrand section straddles the Tithonian/Berriasian boundary and reaches the middle Berriasian sensu lato. 相似文献