Geosciences

Amfilochia Bay (Eastern Amvrakikos Gulf, Western Greece), a complex marine area affected by tectonism, was investigated for seabed seepage manifestations and for possible inter-relationships between shallow gas accumulations and hypoxia. For this purpose, an integrated research methodology that combined geophysical, geochemical, and hydrographic surveys was applied. Marine geophysical and bathymetric surveys led to the discovery of a gas-induced pockmark group in the study area. Oceanographic surveying confirmed that the bay is hypoxic/anoxic below a depth of 15 m (dissolved oxygen from ~4 to 60 μM). Very weak CH4 seepage was detected in correspondence to the pockmark group that seemed to slightly enhance the hypoxic environment locally and close to the seabed, with no effect in shallower waters and the oxycline. Methane isotopic analysis showed variable carbon isotopic composition (from −41‰ to −86‰) which could be either related to differential CH4 oxidation or mixing between micr...

The coastal strip between the Volta River delta and the westernmost portion of Benin (West Africa Margin of Atlantic Basin) is highly populated (e.g., Lomé) due to migrations from inland areas. The coastal zone has proved to be very vulnerable because of the potential development of sometimes catastrophic events related to different and interacting causes, resulting in negative effects on natural ecosystems and socio-economic conditions. The main problem is the marked erosion of large coastal sectors with maximum retreat rates of the order of 5 m/year. The continuous loss of territory leads to a progressive impoverishment of activities and human resources and to the increase of geological risk factors. The coastal erosion is induced both by natural and anthropic causes and can be controlled only by means of prevention programs, detailed scientific studies and targeted technical interventions. The main erosional processes observed in the study area are triggered by the presence of th...

The cross-correlation technique was applied to ambient seismic noises to investigate the upper crustal velocity structure of the southern Korean Peninsula based on surface wave group velocities. We used seismograms recorded continuously during August 2005 at 91 accelerograph stations in the southern Korean Peninsula. From the correlation results of 4095 data pairs, the arrival times of Green’s functions along paths between stations of pairs were measured in discrete bins of frequency bands with central frequencies of 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, and 0.45 Hz. The spatial distribution of arrival times for each frequency band bin was inverted to obtain a two-dimensional tomographic map of Rayleigh wave group velocity. For each tomographic cell of the maps, we derived dispersion curves by extracting group velocities at center frequencies of the 7 frequency band bins. Shear-wave velocity obtained by depth inversion of the dispersion curve at each cell produced a one-dimensional velocity profile at depths. After aligning the profiles corresponding to tomographic cells, we obtained a three-dimensional uppermost crustal velocity model at depths down to approximately 8 km in the southern Korean Peninsula. These results show low-velocity distributions in the Gyeongsang Basin, western Gyeonggi Massif, and the area of Jeju Island and its northeastern coast. The Okcheon Fold Belt and Yeongnam Massif have relatively high velocity distributions. The low-velocity distribution in the Gyeongsang Basin shrinks in northsouth direction at depths around 4 km and widens again with a tendency to migrate to the east as the depth is increased. However, the linear trend of low velocities in NNE-SSW direction at deeper depths (6.25–8.25 km) in the western area distinctively coincides with the western boundary of the Gyeongsang Basin. The background noise analysis in this study provided the constraining information for determination of depth variation in the shear-wave velocity distribution.

Vegetation cover degradation is still a very common problem in many parts of Morocco; moreover, it affects straight up the amount of the annual soil loss rate. The analytical approach used in this study, respectively, includes remote sensing techniques, application of USLE (Universal Soil Loss Equation) and overlay analysis in a raster Geographic Information System (GIS) environment, employing available information on the region covering the Kalaya catchment. Thus, this procedure allowed the calculation of the NDVI (Normalized Difference Vegetation Index), the execution of two types of classification (unsupervised and supervised) for 1999 and 2010 imagery and eventually the prediction of soil erosion risk in the watershed in question. The main outcome was the production of multidate vegetation cover maps, land use maps and soil loss risk maps. The overlay of two maps allowed us to highlight the changes occurred in this area, which evidence the high anthropogenic impact on the dynami...

The geological education in Greece has its roots in the second half of the 19th century, but it was established as a «necessary» science at the end of the above century. The sample of the present paper are several articles in literary and scientific journals of 19th and 20th century, such as the ESTIA, PARNASSOS, PANDORA, KLEIO and the PROMITHEUS, which reflect the size of the conflict of scientists of the above period. This paper examines how the Geology Science is presented through these above scientific magazines

Bregman iterative algorithms have been extensively used for l1 and TV regularization problems,
allowing to obtain simple, fast and effective algorithms. In this paper, a coordinate descent algorithm for
geosounding inversion is modified by including a Bregman iterative procedure in the linearization.
Modeling results are presented for synthetic data, observing better convergence properties than the original
versions, avoiding the need of the continuation descent procedure.

In Australia, geotourism is defined as tourism which focuses on an area's geology and landscape as the basis for providing visitor engagement, learning and enjoyment. Geotourism has great potential as a new nature-based tourism product. Where-ever tourism contributes a direct environmental benefit to a visited location, its clients gain empathy for the holistic heritage of the area, and this reward creates enhanced customer loyalty to the operator. The Australian Government’s 1994 National Ecotourism Strategy considered that ecotourists may include a mix of independent travelers, people who travel in organised groups of a scientific, educational or recreational nature, and individuals or families who are interested in an ecotourism experience as part of a varied holiday. Having regard to demographic and lifestyle considerations, it had been considered that geotourism, if positioned as an alternative, knowledge-adding product could attract a different demographic i.e. affluent ov...

Cyprus has a long history of tsunami activity, as described in archaeological and geological records. Although the study area has experienced tsunamis in the past and constitutes an area threatened by this hazard both from the Cyprean arc and from the neighboring Hellenic arc, field research on tsunami evidence on the coastal zone of Cyprus still remains scarce. It is clear from the literature that large boulder accumulations are an important feature along the coasts of Cyprus, testifying to extreme events. A detailed field survey revealed that at various locations cited in the literature as hosting geomorphological evidence of past tsunamis, no such evidence was identified. It is likely that the high touristic activity that has been occurring on the coasts of Cyprus during the last 20 years may have affected tsunami indicators such as boulder accumulations. Tsunamis are unpredictable and infrequent but potentially large-impact natural disasters. The latest strong tsunami that cause...

Students in Environmental Field Studies class at the University of Montana Western (UMW) in Dillon, Montana conducted a baseline inventory and assessment of Poindexter Slough, a former channel of the Beaverhead River located approximately 3.0 miles south of Dillon, MT.  During the period of September 22nd to October 15th, 2014, the students assessed the stream morphology, in-stream macroinvertebrates, riparian vegetation and stream habitat for the entire 4.73-mile length of Poindexter Slough. The purpose of the study was to gather baseline data to assess a fish-related riparian restoration and improvement project by the Montana Fish, Wildlife and Parks and The Beaverhead Watershed Committee. The project was supervised by Dr. Robert C. Thomas, Professor of geology in the Environmental Sciences Department at UMW.

The study area included twenty-two cross-sections placed from the diversion of the slough from the Beaverhead River to its confluence back with the river. The cross sections were chosen to achieve a good assessment of the entire slough. The cross sections were placed across riffle-pool pairs and their positions recorded with GPS. The study was designed to (1) assess the existing conditions, and (2) make recommendations about the restoration plan. Future UMW students will use the data for a long-term assessment of the restoration project through repeated analyses. Restoration plans involve replacing existing irrigation infrastructure, mechanically modifying channel dimensions, and transplanting riparian vegetation to improve fisheries habitat and restore natural processes of habitat formation and maintenance to the slough. The majority of Poindexter Slough functions as an “A4” stream, but it should be functioning as a “C4” stream, with far less fine-grained sediment load.

Based on the assessment data, the UMW team recommended the removal and prevention of fine-grained sediment accumulation in Poindexter Slough. Since the macroinvertebrate diversity is greatest in areas of in-stream vegetation, the team recommended minimal disturbance of these areas during restoration work. The team proposed a protocol for reducing noxious weeds in the riparian areas that will be disturbed by the restoration work, and the report was submitted to Montana Fish, Wildlife and Parks to be used to modify their restoration plan for the slough.

Today (year 2020), the globally recognized problem of arsenic (As) contamination of water resources and other environments at toxic levels has been reported in all of the 20 Latin American countries. The present review indicates that As is prevalent in 200 areas across these countries. Arsenic is naturally released into the environment and mobilized from geogenic sources comprising: (i) volcanic rocks and emissions, the latter being transported over thousands of kilometers from the source, (ii) metallic mineral deposits, which get exposed to human beings and livestock through drinking water or food chain, and (iii) As-rich geothermal fluids ascending from deep geothermal reservoirs contaminate freshwater sources. The challenge for mitigation is increased manifold by mining and related activities, as As from mining sites is transported by rivers over long distances and even reaches and contaminates coastal environments. The recognition of the As problem by the authorities in several ...

Cyprus has a long history of tsunami activity, as described in archaeological and geological records. Although the study area has experienced tsunamis in the past and constitutes an area threatened by this hazard both from the Cyprean arc and from the neighboring Hellenic arc, field research on tsunami evidence on the coastal zone of Cyprus still remains scarce. It is clear from the literature that large boulder accumulations are an important feature along the coasts of Cyprus, testifying to extreme events. A detailed field survey revealed that at various locations cited in the literature as hosting geomorphological evidence of past tsunamis, no such evidence was identified. It is likely that the high touristic activity that has been occurring on the coasts of Cyprus during the last 20 years may have affected tsunami indicators such as boulder accumulations. Tsunamis are unpredictable and infrequent but potentially large-impact natural disasters. The latest strong tsunami that cause...

This report provides details of activities undertaken by the Australian Institute of Marine Science (AIMS), Geoscience Australia (GA), the University of Western Australia and the Museum and Art Gallery of the Northern Territory during a marine biodiversity survey to the Oceanic Shoals Commonwealth Marine Reserve (Timor Sea) in 2012. The survey was an activity within the Australian Government’s National Environmental Research Program Marine Biodiversity Hub and the key component of Theme 4 – Regional Biodiversity Discovery to Support Marine Bioregional Plans. Data collected during the survey will be used to support research being undertaken in other Themes of the Marine Biodiversity Hub, including the modelling of ecosystem processes for the northern region, and to support the work programs of the Department of the Environment (previously Department of Sustainability, Environment, Water, Population and Communities). These data will be made publicly available, via the Marine Biodiversity Hub website and the Australian Ocean Data Network Portal, adding to the knowledge base of Australian tropical shelf habitats and contributing to the long term management of these poorly understood areas.