Mapping and evaluating the condition of artificial levees

Artificial levees along alluvial rivers are major components of flood risk mitigation. This is especially true in the case of Hungary, where more than one-third of the country is threatened by floods and protected by an over 2940-km-long levee system. Most of the levees were built in the 19th century. Since then, several natural and anthropogenic processes, such as compaction, erosion, Etc., could contribute to these earth structures' slow but steady deformation. Meanwhile, as construction works were scarcely documented, the structure and composition of artificial levees are not well known. Therefore, the present analysis aimed to use different geophysical techniques to validate their efficiency in mapping structural differences, possible compositional deficiencies, potential defects and sections where elevation decrease and compare the compositional and structural variations of two very different levee sections along a 24 km section of the River Tisza and a 24 km section of the River Maros. Investigations were conducted by real-time kinematic GPS (RTK-GPS), Ground penetrating radar (GPR), Electrical Resistivity Tomography (ERT) and drillings. Onsite data acquisition was complemented with an analysis using a Persistent Scatterer Synthetic Aperture Radar (PSI) to assess general surface deformation. The higher frequency 200 MHz GPR data have shown that levee structures can significantly vary even in a few km on sections with the same construction history. Based on electrical resistivity tomography results with a precise analysis of grain size and their related physical parameters used for monitoring the materials of two different levee sections along the Tisza and Maros rivers, we noticed that the main components of investigated Tisza levee section are medium and fine silts, however, the situation of the investigated Maros levee section shows more variation of different materials which are fine, medium, and coarse silt, moreover, fine, medium, and coarse sand. The investigated section of the Tisza levee showed low resistivity values, indicating the fine-grained materials' conductivity. In contrast, the investigated section of the Maros levee showed high resistivity values, indicating the resistivity nature of higher grain size sediments forming this section, especially noticed on the protected side of the levee. It was possible to capture structural changes and resolving the thin layers by 1 m electrode spacing ERT profile. In turn, at a larger spacing it was possible to get information on the sedimentary base below the levee body. The selected levee section could be assessed in terms of its structure and composition and major units within the levee body and their composition could be resolved by the applied methods. In general, there is a similarity in the materials and their resistivity range which form the core of Tisza and Maros levees, however, the situation on their both sides is not the same. Regarding the analysis of different physical properties of the two levee systems like resistivity, porosity, density, water content, grain size, and saturated hydraulic conductivity, the materials of the Maros levee could be distinguished well and showed more variation when it is compared to the materials of Tisza levee. It means that the physical properties of levee materials are very important, and they are recommended when carrying out further levee investigations. From the physical properties mentioned above, it was found that some of them show a connection with resistivity except hydraulic conductivity parameter that did not show a direct connection, however the latter could exhibit the aquitard nature of Tisza levee materials and the non-aquitard nature of Maros levee materials which illustrates the difference in levee composition in terms of flood risk or flood safety. Based on height measurements, the mean elevation of the levee crown decreased by 8 cm in a 40-year time span. However, elevation decrease could reach up to 30 cm at some locations. Sections affected by structural anomalies, compositional changes, and increased surface subsidence are especially sensitive to floods when measurement results are compared to flood phenomena archives. GPR profiles showed several anomalies, including structural and compositional discontinuities and local features. They were classified into six types regarding to the flood risk; tensile cracks (enables piping, leading to levee breach or mass failure, cracks might close when the levee gets wet), remarkable changes in dielectric permittivity (enables seepage, leading to mass failure), animal burrows (enables piping, leading to levee breach or mass failure), layer deformation (results in height decrease, overtopping), paleo river channel (enables seepage below the levee, leading to water upwelling and the development of sand boils), sudden change in stratification or dipping layers (enables contour line seepage, leading to mass failure). The penetration dept

Gravity observations at Sinai Peninsula and its geophysical and geodetic applications

AbstractSouth Sinai is an interesting region from both tectonic and seismological settings. Tectonically, Sinai Peninsula is strongly dominated by its active boundaries due to its location at the triple junction among the Gulf of Suez rift, the Aqaba–Levant transform fault and the Red Sea Rift. Moreover, reported seismological activities along the three tectonic boundaries indicate its continuous activities.It is thus of great interest to delineate the subsurface geological structure responsible of its tectonic settings and its relation to the seismological activity. Therefore, terrestrial gravity observation has been carried out to figure out the sub-surface structure representing its tectonic settings.On the other hand, the location of Sinai Peninsula between Gulf of Suez, Gulf of Aqepa and Red Sea has made the satellite altimetry data an optimum tool to determine the Gravity sources on the marine regions bounding the Sinai region. Finally, temporal gravity variation of the GRACE satellite mission, launched in 2003 gives the opportunity to monitor its temporal gravity variation on regional scale. Temporal gravity variation from GRACE demonstrates any possible mass redistribution along the pounding tectonic settings and its relation to seismicity.Observed gravity map shows significant gravity anomalies attributed to tectonic and seismicity. Satellite altimetry and gravity data are considered to be a valuable source of data to determine the offshore subsurface structure. Temporal gravity variations from GRACE shows important zones of mass redistribution attributed to its new tectonics and its relation to the seismological activities. Integrating all available data sheds more light on the geodynamic behavior of the selected region and its relation to the seismic activities

Comparative evaluation of the material of the artificial levees : A case study along the Tisza and Maros Rivers, Hungary

Artificial levees have major importance in protecting human livesand infrastructure as they are essential elements of the flood protectionmeasures. Nevertheless, the lack of the necessary information about theirstructure and internal composition might cause high risks. To monitor theirstability, integrated surveys are needed, including geophysical andgeotechnical methods. Levees along the rivers in Hungary were constructedmore than 150 years ago, and they were heightened several times; therefore,investigations are required to assure their performance in flood riskmitigation. Our investigation aimed to utilise non-invasive geophysicaltechniques, primarily electrical resistivity imaging, with the validationof geotechnical investigations to map and compare the compositional andstructural variations of two very different levee sections along RiverTisza and River Maros. Integrating the analysed drilling data with ERTprofiles showed that the main composition of the investigated Tisza leveesection is fine and medium silt with an average resistivity 30 Ωm, however,the investigated section of Maros levee was built of not only of fine andmedium silt but also of medium and coarse sand exhibiting higherresistivity values reaching up to 2200 Ωm. Several physical parameters weremeasured to study the nature of constituting levee materials like moisturecontent, grain-size, porosity, bulk-density, saturated hydraulicconductivity, and resistivity. It was found that most of them show aconnection with resistivity, but the hydraulic conductivity did not show adirect connection, however the latter could exhibit the aquitard nature ofTisza levee materials and the non-aquitard nature of Maros levee materials

The Potential Use of Osl Properties of Quartz in Investigating Fluvial Processes on the Catchment of River Mureş, Romania

To understand the functioning of fluvial systems it is important to investigate dynamics of sediment transport and the source of sediments. In case of reconstructing past processes these studies must be accompanied by the numerical dating of sediment samples. In this respect optically stimulated luminescence is a widely used technique, by which the time of sediment deposition can be directly dated. Recently, in various fluvial environments it has been shown that certain luminescence properties of minerals, and especially that of quartz, can be applied as indicators of fluvial erosion and/or sediment provenance. These properties are residual luminescence (or residual dose) and luminescence sensitivity of quartz grains. However, the values of the parameters above are affected by various factors, the importance of which is under debate. The present study therefore aims to assess these factors along a ~560 km long reach of River Mureş (Maros) a relatively large river with a compound surface lithology on its catchment. The research focused on the sandy fraction of modern sediments, collected from the main river and from three tributaries alike. This way not only longitudinal downstream changes, but the influence of tributaries could also be studied. Based on the data, both investigated parameters show a great variation, which can be attributed to the lithological differences of subcatchments and geomorphological drivers, such as erosional activity and potential number of sedimentary cycles, and human activity. However, relationships are not entirely clear and are influenced by the maximum grain size of the samples investigated, and the recycling of previously laid deposits with different properties. Still, when performing detailed dating studies, and tracing sediments from certain parts of the catchment luminescence properties can be a useful tool in the future

The potential use of osl properties of quartz in investigating fluvial processes on the catchment of river Mureş, Romania

To understand the functioning of fluvial systems it is important to investigate dynamics of sediment transport and the source of sediments. In case of reconstructing past processes these studies must be accompanied by the numerical dating of sediment samples. In this respect optically stimulated luminescence is a widely used technique, by which the time of sediment deposition can be directly dated. Recently, in various fluvial environments it has been shown that certain luminescence properties of minerals, and especially that of quartz, can be applied as indicators of fluvial erosion and/or sediment provenance. These properties are residual luminescence (or residual dose) and luminescence sensitivity of quartz grains. However, the values of the parameters above are affected by various factors, the importance of which is under debate. The present study therefore aims to assess these factors along a ~560 km long reach of River Mureş (Maros) a relatively large river with a compound surface lithology on its catchment. The research focused on the sandy fraction of modern sediments, collected from the main river and from three tributaries alike. This way not only longitudinal downstream changes, but the influence of tributaries could also be studied. Based on the data, both investigated parameters show a great variation, which can be attributed to the lithological differences of subcatchments and geomorphological drivers, such as erosional activity and potential number of sedimentary cycles, and human activity. However, relationships are not entirely clear and are influenced by the maximum grain size of the samples investigated, and the recycling of previously laid deposits with different properties. Still, when performing detailed dating studies, and tracing sediments from certain parts of the catchment luminescence properties can be a useful tool in the future

A dombói vár tégláinak kormeghatározása termolumineszcens módszerrel

A dombói vár Dombóvár városától délre, egy a Kapos folyó árteréből kiemelkedő dombon helyezkedik el. Az egykori várból ma mindössze három vegyes tégla-kő alapanyagú faltömb és egy téglaépítésű pillér maradványa látható. A lelőhely szisztematikus régészeti kutatása 2014-ben kezdődött, és azóta is folyamatosan tart. Az eddigi ásatások eredményei alapján a vár építésétől az 1702. évi fennállásáig öt nagyobb építési periódust lehet elkülöníteni. A hagyományos régészeti módszerekkel történő keltezés azonban több szempontból is megerősítésre szorul, ugyanis a datáló értékkel bíró leletek, a lelőhely nagyfokú pusztulása és a közelmúltig tartó bolygatások miatt, nem eredeti helyükről kerültek elő, hanem másodlagos vagy harmadlagos feltöltésekből. A vár keltezésének problematikájából kifolyólag, illetve figyelembe véve, hogy az erősség legnagyobb része téglából épült, a termoluminsezcens (TL) kormeghatározás tűnt a leginkább alkalmazható abszolút kormeghatározási módszernek. Kutatásunk célja az egyes építési fázisok kronológiájának meghatározása TL kormeghatározás segítségével, illetve a meglévő, régészeti alapon felállított periodizáció pontosítása, esetleges felülvizsgálata. A TL kormeghatározás segítségével kerámiák, cseréptárgyak, terrakotta műalkotások, valamint téglák és egyéb iparrégészeti vonatkozású objektumok kiégetési ideje állapítható meg. Vizsgálatainkhoz 13 téglamintát gyűjtöttünk a vár különböző pontjairól. A TL mérések során az additív módszert alkalmaztuk, a mérésekhez a legoptimálisabb beállításokat pedig plató tesztekkel állapítottuk meg. Az eredmények pontosítása érdekében fakulási teszteket és az α-hatásfokra vonatkozó vizsgálatokat is végeztünk. Az építési periódusokra vonatkozó eredményeinket igyekeztünk több minta átlaga alapján megadni. A TL mérés által kapott koradatok többsége megfelelően igazodott a régészeti módszerekkel meghatározott korokhoz, két építési fázis esetében viszont további elemzések elvégzésére van szükség, mivel csak egy-egy minta alapján történt az értékelés. Vizsgálataink mindemellett rámutattak arra is, hogy elengedhetetlenül fontos az α-hatásfok közvetlen mérése, valamint hogy lehetőség szerint egy jelenségből több minta gyűjtésével a mérési eredmények pontosíthatók

Bioactive pyrrole alkaloids isolated from the Red Sea : marine sponge Stylissa carteri

Fifteen pyrrole alkaloids were isolated from the Red Sea marine sponge Stylissa carteri and investigated for their biological activities. Four of them were dibrominated [(+) dibromophakelline, Z-3-bromohymenialdisine, (±) ageliferin and 3,4-dibromo-1H-pyrrole-2-carbamide], nine compounds were monobrominated [(-) clathramide C, agelongine, (+) manzacidin A, (-) 3-bromomanzacidin D, Z-spongiacidin D, Z-hymenialdisine, 2-debromostevensine, 2-bromoaldisine and 4-bromo-1H-pyrrole-2-carbamide)] and finally, two compounds were non-brominated derivatives viz., E-debromohymenialdisine and aldisine. The structure elucidations of isolated compounds were based on 1D & 2D NMR spectroscopic and MS studies, as well as by comparison with literature. In-vitro, Z-spongiacidin D exhibited a moderate activity on (ARK5, CDK2-CycA, CDK4/CycD1, VEGF-R2, SAK and PDGFR-beta) protein kinases. Moreover, Z-3-bromohymenialdisine showed nearly similar pattern. Furthermore, Z-hymenialdisine displayed a moderate effect on (ARK5 & VEGF-R2) and (-) clathramide C showed a moderate activity on AURORA-A protein kinases. While, agelongine, (+) manzacidin A, E-debromohymenialdisine and 3,4-dibromo-1H-pyrrole-2-carbamide demonstrated only marginal inhibitory activities. The cytotoxicity study was evaluated in two different cell lines. The most effective secondary metabolites were (+) dibromophakelline and Z-3-bromohymenialdisine on L5178Y. Finally, Z-hymenialdisine, Z-3-bromohymenialdisine and (±) ageliferin exhibited the highest cytotoxic activity on HCT116. No report about inhibition of AURORA-A and B by hymenialdisine/hymenialdisine analogs existed and no reported toxicity of ageliferin existed in literature