Statistical behaviours of earthquake occurrences in the Central Anatolian Region of Turkey: region-time-magnitude analyses

The main objective of this work is to make detailed region-time-magnitude analyses by describing the statistical behaviours of earthquakes in the Central Anatolian Region of Turkey. In this scope, several seismic and tectonic parameters such as Mcomp, b-value, Dc-value, Z-value, recurrence times and annual probabilities were evaluated. For the analyses, a homogeneous catalogue including 10,146 earthquakes with 1.0 ≤ Md ≤ 5.7 between 30 July 1975 and 29 December 2018 was used and spatio-temporal changes of earthquake behaviours were mapped for the beginning of 2019. Earthquake magnitudes varied from 1.9 to 3.0 on average, and hence Mcomp was considered to be 2.6. The b-value was calculated as 1.26 ± 0.07, and this relatively large value indicates that small-magnitude events are dominant. The Dc-value was computed as 1.31 ± 0.03. This small value means that distances between epicentres approach the diameter of the cluster, and seismic activity is more clustered at smaller scales or in larger regions. The spatio-temporal analyses of recurrence times suggest that the Central Anatolian Region has an intermediate/long-term earthquake hazard in comparison to occurrences of strong earthquakes in the short term. Several anomaly regions of a small b-value and a large Z-value were found in and around the Tuzgölü Fault Zone, Central Anatolian Fault Zone, Salanda fault and Niğde fault at the beginning of 2019. Thus, a combination of the regions with a lower b-value, a higher Z-value and also moderate recurrence times may give significant clues for the future possible earthquakes, and detected regions may be thought to be the most likely areas for strong/large events in the Central Anatolian Region.

Modelling of underwater noise emissions by ships in Klaipėda Strait, Lithuania

One of the United Nations Sustainable Development Goals regarding “conservation and sustainable use of the oceans, seas, and marine resources” emphasizes the urgency of eliminating harmful effects on the sea and its biota, where the role of anthropogenic activities is crucial. The global trend of merchant shipping is increasing, thus enlarging underwater noise levels. As a result, greater noise can harm aquatic animals in their habitats. In the Baltic Sea, the underwater sound pressure levels are now being evaluated utilizing noise measurement, modelling, and mapping. In areas such as narrow ship passages, namely lagoons, channels, or straits, the ambient underwater noise modelling becomes very complex, even though these EU inland waters are regarded by legislation as part of the marine basin. For instance, the Klaipėda Channel (Klaipėda Strait), connecting the Baltic Sea and the Curonian Lagoon, is regarded by the national Lithuanian legislation as part of marine waters, where the environmental status should be evaluated according to the EU Maritime Strategy Framework Directive. In this narrow channel, an alternative to the modelling of ambient sound pressure levels can be applied to understand the long-term trends of vessel-sourced noise emissions. In this paper, an example of application of ship noise emission modelling for a narrow Klaipėda Harbour area is presented, along with the results obtained throughout 2015–2017. The modelled noise levels in the harbour area reached the median levels of 112.5 dB in 2015 and 102.6 dB re 1 µPa2 in 2017. The maximum emitted instantaneous sound pressure levels by ships reached 173.7 dB in 2015 and 179.4 dB re 1 µPa2 in 2017 in the area of interest.

Metamorphism of the Dizi Series Rocks (the Greater Caucasus): Petrography, Mineralogy and Evolution of Metamorphic Assemblages

The Dizi Series is exposed within the Southern Slope zone of the Greater Caucasus, in the core of the Svaneti anticlinorium. It is mainly composed of terrigenous, volcanogenic and carbonate rocks faunistically dated from the Devonian to the Triassic inclusive. Regional and contact metamorphism of the Dizi Series rocks was studied. It is stated that the degree of regional metamorphism corresponds to the chlorite-sericite subfacies of the greenschist facies, occurring at a temperature of 300–350°C and a pressure of 1.5–2.3 kbar. As a result of the action of the Middle Jurassic intrusive rock bodies, the regionally metamorphosed rocks of the Dizi Series underwent contact metamorphism. Three zones of contact metamorphism were distinguished corresponding to albite-epidote-hornfels, andalusite-biotite-muscovite-chlorite-hornfels and andalusite-biotite-muscovite-hornfels subfacies. Contact metamorphism took place at a significantly higher temperature and lower pressure than the preceding regional metamorphism. The maximum temperature of the contact metamorphism reached ≈ 570°С, while pressure varied within the range of ≈ 0.3–0.8 kbar. The evolution of rock associations of regional and contact metamorphism of the Dizi Series was studied. The fields of facies and subfacies of regional and contact metamorphism are shown in the Ps-T diagram. Three age populations of zircons were identified using U-Pb LA-ICP-MS dating of the diorite-porphyrite intrusion in the Dizi Series: Zrn1 (ca. 2200 Ma) and Zrn2 (458 ± 29 Ma) that were captured by the diorite-porphyrite magma from the ancient magmatic and metamorphic rocks of the crystalline basement, and Zrn3 (166.5 ± 4.6 Ma) that corresponds to the age of diorite-porphyrite crystallization.

New insight into the palaeoenvironmental dynamics as a background of the human history in the Nemunas River delta region, W Lithuania, throughout the Lateglacial and Early Holocene

A new reconstruction of the Lateglacial – Early Holocene paleoenvironmental dynamics as a background of the habitation history in the territory of the Nemunas River Delta (NRD) was based on the geological-geomorphological, grain-size, isotope (14C), pollen and diatom data supplemented by archaeological information obtained within the framework of the project „Man and Baltic Sea in the Meso-Neolithic: Relict Coasts and Settlements Below and Above Present Sea Level. ReCoasts&People“. The existence of extended proglacial lakes formed during the onset of the Lateglacial was succeeded by a period of low water estuaries or freshwater lagoons as early as 13.8 cal kyr BP. Simultaneously, groups of the Final Palaeolithic population, representing the classic Swiderian culture, inhabited the area. As shores of the Yoldia Sea and Ancylus Lake were situated further westwards (-11 to -24 – -29 m NN), wetlands and lake systems alongside with shallow boggy basins and fluvial streams predominated in the local landscape throughout the Early Holocene. Archaeological data suggest an episodic human activity in the territory while part of the archaeological sites might have been covered by sediments during the further intervals of the Holocene. Since the Early Holocene an extended peat bogs have become an important part of the landscape here.

Undrained shear strength of glacial till soils and its determining factors

This article presents results of the test conducted on the undrained shear strength of till clayey soils of Eastern Lithuania, which are characterized by rigid and very stiff consistency and low plasticity. According to the classification of soils presented in LST EN ISO 14688–2:2018 Geotechnical Investigation and Testing – Identification and Classification of Soil − Part 2: Principles for a Classification, the tested soils are classified as sandy low plasticity clays. The undrained shear strength was tested using the triaxial compression (unconsolidated undrained) method. The test results showed that peculiarities of the particle size distribution had a crucial impact on the undrained strength of these soils, i.e. on the correlation of clay and fine silt fractions with the rest of soil components.

Phytoplankton of the transboundary River Viliya (Neris): community structure and toxic cyanobacterial blooms

The 2011–2012 data on the hydrochemical mode of the transboundary River Viliya (Neris) and two of its tributaries in the territory of the Republic of Belarus and on structure of the phytoplankton community therein are presented. High phytoplankton biomass was determined in the summer period. For the first time, the presence of microcystin synthase genes (mcyE) was detected in the River Viliya (Neris), and four variants of microcystins were determined employing the MALDI-TOF method. Similarities in the species composition (including toxic species) of cyanobacteria from the River Viliya (Neris) and from the Curonian Lagoon of the Baltic Sea were noted. It can be assumed that the phytoplankton community structure of rivers can influence algal community formation in the downstream areas as well as in the coastal estuarine lagoons that eventually receive water from these rivers.

Contribution of winter upwelling in the Gulf of Finland to lake-effect snow in Estonia

The aim of the study was to analyse the sequence of winter (“warm”) upwelling and lake-effect snow (LES) events that deposited up to 50 cm of snow along the North Estonian coast in January–February 2021. Based on weather and aerological data, four episodes of LES were documented. Heavy, localized lake-effect enhanced precipitation occurred along a 30–50 km wide coastal strip bordering the Gulf of Finland when a cold air mass from the north advected over the warmer, unfrozen sea surface. A temperature difference of up to 20°C was revealed between the air mass temperatures measured at the 850 hPa level and at the sea surface. The LES events, in turn, were preceded by upwelling in the southern Gulf of Finland, which was generated by persisting easterly winds. Even when occasionally interrupted by a wind change, the upwelled water still kept sea surface temperature (SST) in the southern half of the Gulf higher, as documented by the water temperature records from the coastal stations of Estonia, SST and salinity imagery retrieved from the SatBaltyk system, and sea ice distribution charts. Differently from summer (cold) upwelling, winter upwelling brought up warmer (2–4°C) water from the sub-surface layers replacing the already cooled down (0–1°C) surface water. Thus, winter upwelling enhanced LES in two ways. Firstly, by not letting the Gulf freeze over, and therefore by providing a fetch. And secondly, by increasing the SST (and therefore also the 850 hPa level – surface temperature difference) by up to 4°C.

Environmental issues in the coastal regions of the south-eastern Baltic Sea: A sensitive natural environment in the face of increasing anthropic pressures

In recent years, Latvian, Lithuanian, and the Oblast of Kaliningrad coastal zones have been experiencing a particularly intense and rapid anthropisation of the coastline due to political, social, and economic changes at the end of the Soviet period. These pressures are exerting on a highly sensitive environment, which has remained relatively untouched by any major development due to the militarisation of the coasts. The human stakes increased considerably in the coastal zone of the south-eastern Baltic with tourism, industrial development, and urban expansion. The environmental impacts and issues of the post-soviet anthropisation are analysed in this article through a bibliographic compilation related to the evolution of the coastal management policies reconciling environmental protection and economic development.

Overview of the Quaternary sediments deformation modulus dependence on testing methodology

The surface of earth on the territory of Lithuania is covered by sediments of the Quaternary system, which are the object of human economic activities. Reliable assessment of sediment deformations is an important task of modern engineering geology and geotechnical engineering. The deformation of sediments is most often described using the modulus of deformation. The current article overviews different methods employed in deformation moduli determination and their application possibilities. The deformation moduli, which are used in various calculations, are usually calculated using correlation formulas and empirical coefficients. Thus, the obtained results may be inaccurate or completely unsuitable for further interpretation of the numerical situation. This article presents recommendations with regard to the use of various calculated deformation moduli in interpreting Lithuanian Quaternary system sediments.

A new methodology to assess landscape reserves in Lithuania

The first state reserve in Lithuania was established in 1960; however, no detailed assessments of changes in the state of the protected values therein have been performed ever since. Landscape reserves are the most complex ones and they pursue the twofold goal – to conserve the values and to use them sustainably. In order to be resilient themselves, thus contributing to broader objectives of social-ecological resilience, the reserves should be able to adapt to ever-changing social and ecological conditions in a way that supports the long-term persistence of population, communities, and ecosystems of conservation concern. Therefore, it is necessary to update information on the status of values protected in the reserves. The article addresses this need by offering a concise and user-friendly methodology for assessing the status of landscape reserves. The methodology focuses on three main components: (1) general features of the landscape structure, (2) the effectiveness of protection of values and (3) the pressures and threats they experience. Two state landscape reserves were selected for testing the applicability of the methodology: one in Vilnius city, the other 50 km to the west, in the countryside. Application of the common methodology will allow to assess the condition of landscape reserves in the country. Further development of the methodology could include evaluation of external pressures (e.g. urbanization) as well as addition of remote sensing techniques.