Age, Genesis, and Seismogenic Deformations of the Vuoksa River Terraces on the Karelian Isthmus (Northwestern Russia)

—Terraces at four hypsometric levels were studied in the Vuoksa River basin (northern part of the Karelian Isthmus, NW Russia). New data on nine sections of late Quaternary–Holocene sediments have been obtained. Their age has been determined (for the first time for surface deposits in the studied region) in the interval from 90 to 2 ka. The terrace sediments are disturbed by deformations (faults, folds, and liquefaction) caused by six strong earthquakes in that period. The relationships among the terrace levels, ages, stratigraphy, and structures of loose sediments point to their formation under the impact of differentiated tectonic motions triggered by the activation of the ancient “Vuoksa” fault zone in the late Neopleistocene and Holocene.

Scree formation on nonmining flank of an opencast and its impact on vegetation restoration

The purpose of the conducted research is to study the regularities of scree formation and assess their impact on self-vegetation of disturbed lands after mining of building stone deposits. The processes of natural formation of scree have been studied, their layering and gravitational alignment have been determined, the factors causing pit bench collapse have been identified. Simulation of the scree formation process allowed to establish the dependence of rock spreading distance on bench height, bench slope angles, as well as on the weight of individual pieces. The slope bench angles with the largest and smallest rock spread distance were found. The simulation showed the influence of the slope bench angles and parameters of the scree formed at the foot of pit benches on the range of debris spread. Three distinct formation stages of scree at the foot of the benches are identified. The angles of transition from one stage of scree formation to another are determined. Recommendations are given to improve the conditions of self-vegetation and minimize the negative factor of scree formation. To form a layer of loose sediments on horizontal bench sites it is proposed to use rocks from scree, which can dramatically reduce the cost of reclamation rather than imported man-made mixture or potentially fertile soils. In order to increase self-vegetation intensity on the flanks of opencasts, it is recommended to increase the bench height and berm width without changing the design angle of the opencast flank slope. To reduce the adverse impact of scree formation on vegetation restoration on the sides at the bench foot, it is proposed to form a trench collecting falling rocks or a rockprotecting wall.

Features of the glacial formations structure and bottom relief forms related to them according to seismoacoustic profiling data and their role in the decision of discussion issues of the quarterly cover formation of the Barents Sea

Hot questions in the modern Quaternary geology of the Arctic seas associated with their glaciation are discussed in this article. The questions of the history of the occurrence of the problem of shelf glaciation or “drift” accumulation of boulder-bearing sediments are considered in detail. The results of seismic-acoustic studies and their interpretation with the aim of seismic stratigraphic and genetic partition of the cover of loose sediments of Quaternary age are considered in detail. Arguments are presented in favor of the continental origin of glaciers (Novaya Zemlya, Ostrovnoy and Scandinavian), which in the late Neopleistocene spread to the shelf of the Barents Sea and occupied its surface to depths of 120−150 m. Further development of glaciation was already due to the expansion of the area of shelves glaciers. The facies zoning of glacial-marine deposits is estimated, which is related to the distance from the front of the glaciers. It is concluded that already at the end of the Late Pleistocene, most of the modern Barents Sea was free from glaciers and from the annual cover of pack ice. Data on the absence of the area distribution of frozen sediment strata within the modern Barents Sea shelf are presented.

Isotope-hydrogeochemical features of the Belokurikha field radon waters

The purpose of the work is to carry out integrated isotope-geochemical studies of the mineral waters of the Belokurikha deposit. The methods of titrimetry, ion chromatography, inductively coupled plasma mass spectrometry (ICPMS) have been used in the laboratory investigation of the chemical composition of waters. The isotope composition of oxygen, hydrogen and carbon in dissolved carbon dioxide has been studied with the help of the Isotope Ratio Mass Spectrometer FinniganTM MAT 253 equipped with the attachments for sample preparation H/Device (to analyze the δD ratio) and GasBench II (to analyze δ18O and δ13СDIC ratios). There are two aquifers at the deposit. The first nonartesian aquifer comprises loose sediments of the Quaternary age. The second artesian aquifer includes the granites of the upper Paleozoic age with the different fracture degree: from monolith to loosened. Three groups of waters are distinguished on the basis of geochemical coefficients: fracture-vein waters bedded in weathered granites; groundwaters of the zone of rare earth mineralization and background composition; surface waters of the Belokurikha river. The isotope data on oxygen and hydrogen provide evidence that the production aquifers of the Belokurikha field are fed through the infiltration of meteoric waters, with the feeding shift to winter precipitation. The paper provides the first data of the integrated isotope-hydrogeochemical studies of nitric-siliceous low-radon thermal waters of the Belokurikha deposit. The composition of these waters is HCO3-SO4 Na and SO4-HCO3 Na with the total dissolved salts value ranging from 198 to 257 mg/dm3. The waters are characterized by alkaline pH of 8.6–9.6, silicon content ranging from 19.8 to 24.6 mg/dm3, and they are referred to the fracture-vein waters of the Upper Paleozoic granites. 222Rn activity is up to 359 Bq/dm3. The ratios of δD (from -126.9 to -102.7 ‰) and δ18O (from -17.5 to -14.2 ‰) in the studied waters indicate their atmospheric origin. The values of δ13СDIC vary from -9.7 to -25.6 ‰ and point to the biogenic origin of carbon.

PENGARUH PENAMBAHAN SERBUK BATA MERAH TERHADAP NILAI CBR

Soil is a collection of minerals, organic matter and relatively loose sediments that are located above the bedrock. Based on the particle size, it is divided into four types, namely gravel, sand, silt and clay. The role of soil is very important in a construction because the soil functions as a support for the loads that are above it, so that the soil is expected to have a good bearing capacity. In this study, the soil taken is soft soil in Hambalang, Bogor where the soil conditions in the area are hard in the dry season and soft in the rainy season, so it is necessary to review the CBR (California Bearing Ratio) value. In this study, using waste from red brick as an additive to soft soil. CBR testing is appropriate (SNI 1744: 2012), with the CBR Laboratory test soaked and unsoaked. Along with the addition of% red brick powder, the CBR values of soaked and unsoaked (top and bottom) have increased, so that the addition of% content of red brick powder is 15% respectively got a value of 4.55% and 4.9% (soaked) and 17.94% and 19.70 (unsoaked). So, from this CBR test, it was found that the effect of adding red brick powder increases CBR tilapia soaked and unsoaked soft soil of Hambalang. Keywords: Soft Soil, Red Brick Powder,CBR soaked, CBR unsoaked

Low Heat Flow at Shallow Depth Intervals: Case Studies from Belarus

The territory of Belarus belongs to the western part of the Precambrian East European Platform. Its heat flow pattern is representing by alternating low and high heat flow anomalies. An overwhelming majority of heat flow determinations and in general of geothermal observations in Belarus were fulfilled in boreholes finished in the platform cover. Within the Belarusian Anteclise, Orsha Depression, western slope of the Voronezh Anteclise their bottom holes are typically within the zone of active water exchange, where the groundwater circulation sufficiently influences on recorded thermograms. For instance, observed heat flow density for a number of studied boreholes is low and ranges on average from 15–20 until 35–40 mW/m2 within the Orsha Depression. In a number of studied holes in the northern part of the structure, its values are surprisingly low. They are observed within upper horizons of the zone of active water exchange with pronounced groundwater circulation. Permeable rocks within the geologic section comprise the platform cover with a number of freshwater intervals. Their base is spread here up to depths of 150–250 m. The most of heat flow observations within this area were studied in boreholes which depths is only 200–300 m, sometimes less, as deeper wells are seldom within this geologic structure. Groundwater circulation within loose sediments cools them, most of thermograms here have a concaved shape to the depth axis. As a rule, heat flow values are sufficiently lower in a number of intervals in boreholes finished in the freshwater zone, relatively to the heat flow observed within deeper horizons of the platform cover. In some of studied boreholes, the observed heat flow is as low as 5–15 mW/m2. In most cases it has a tendency to stabilise only at intervals deeper than 600–800 m. It is the main reason for observed low heat flow zones.

Co-seismic deformation, field observations and seismic fault model of the Oct. 30, 2020 Mw=7.0 Samos earthquake, Aegean Sea

<p>On 30 October 2020 11:51 UTC a large Mw = 7.0 earthquake occurred offshore of the island of Samos, Greece. In this contribution we present the characteristics of the seismic fault (location, geometry, geodetic moment) as inferred from the processing of geodetic data (InSAR and GNSS). We use the InSAR displacement data from Sentinel-1 interferograms (ascending orbit 29 and descending 36) and the GNSS offsets from eleven (11) permanent stations in Greece and Turkey to invert for the fault parameters. Our inversion modeling indicates the activation of a normal fault north of Samos with a length of 32 km, width of 17 km, average slip of 2.1 m, a moderate dip-angle (37°) and with a dip-direction towards North. The inferred fault is located adjacent to Samos northern coastline, with the top of the slip ~1 km below surface, and ~2 km off-shore at its closest to the island. The earthquake caused the permanent uplift of the island up to 10 cm with the exception of a coastal strip along the NE part of the northern shore (near Kokkari) that subsided 2-6 cm. The effects of the earthquake included liquefaction, rock falls, rock slides, road cracks and deep-seated landslides, all due to the strong ground motion and associated down-slope mobilization of soil cover and loose sediments.</p>

MODERN BELIGERATIVE RELIEF (ON THE EXAMPLE OF YAVORIV MILITARY TRAINING GROUND OF LVIV REGION)

The author establishes the types of relief created for military purposes (beligerative) and analyzes its morphology. The territory of the Yavoriv military training ground in the Lviv region, the largest in Ukraine training complex of various types and kinds of troops, was chosen as an example. The military training ground was established in the 30s of the twentieth century. In the past, Polish infantry, German tank divisions, Soviet troops, and nowadays Ukrainian and international ground and air forces trained here. The area of the landfill is 361.5 km2. It occupies an advantageous position in the terrain, as it is located on an elevated part of the Roztochchya Upland, where the Main European watershed passes. Loose sediments are widespread in the territory, which contribute to the creation of deep and elongated forms of beligerative relief. These are mainly quaternary alluvial sands and detritus of native rocks, aeolian and diluvial loess and sandy loams, alluvial sediments. We consider the beligerative relief as an integral part of the field military fortification. The research was performed on the base of interpretation of large-scale space images, aerial photographs and field studies. The modern beligerative relief observed at the Yavoriv military training ground was classified into positive and negative forms depending on the method of military activity. Positive forms include: 1) hills of command posts for control and surveillance, 2) hills of tank or cannon fortifications, 3) micro-hills of protection against small arms, 4) bunkers (wooden-earth defense points), 5) high-altitude targets and firing positions. Negative forms are as follows: 1) trenches of the defense line and the course of connections; 2) open structures for the protection of personnel: individual trenches, pairs, for several infantry, as well as for shooting lying down, kneeling, standing; 3) trenches for the protection of equipment and heavy artillery weapons; 4) closed structures for personnel protection: dugouts, bunkers, cracks, dugouts; 5) excavations from ruptures of artillery shells. There are more negative forms in the modern military relief. Analysis of space images from different times (1980–1990, 2000–2005, 2015–2019) and modern field observations allowed us to trace the dynamics of beligerative relief forms. The formation of new and most widespread forms occurs in the mid-80 of the twentieth century. At the end of the XX and at the beginning of the XXI century, the existing forms decline, steamrolled by exogenous processes, and new ones do not appear. New forms have been appeared since 2015, but only in small local areas. The place they appear are characterized by a significant anthropogenic transformation of the terrain, the development of exogenous processes, such as soil dispersal, desertification, erosion, oozing. Key words: beligerative (military) relief; Yavoriv military training ground (Ukraine); morphological classification.

Hydro-meteorological preconditions and geomorphological consequences of extreme flood in the small river basin in the wet subtropical zone (the Tsanyk River case study, Sochi region)

The overall increase in precipitation and the frequency of extreme rainfall is confirmed by several meteorological observations both on the Black Sea coast of the Caucasus. In this context, research on the drivers of an extreme meteorological event becoming a severe flood and an extreme geomorphological (erosion) event becomes especially important. The article analyses the factors contributing to the development of a flash flood on the watershed of the river Tsanyk (Great Sochi area) and estimates its geomorphological impact. Analysis of hydrologic-meteorological situation during the Tsanyk flood on 7-9 September 2018 and in the previous period showed that the event is unique for the investigated watershed from the hydrologic perspective. After a prolonged period without precipitation, the rainfall on 7-8 September resulted in a flash flood with a rapid water level rise (117 cm in 40 min). We determined the rates and volumes of channel erosion based on a repeated survey of the channel section, estimation of the speed and length of the banks being flushed out, composed of loose sediments and bedrock using the pin method. The amount of erosion on the banks composed of loosened sediments is on average 2-3 times higher than on the flysch banks. At the same time, the material export for one erosion event in September 2018 is comparable (or even exceeds) the total amount of bank erosion for the year, previously identified based on stationary observations.