Geophysical Characteristics Research Articles

Особенности теплового поля города Ростова-на-Дону по данным дистанционного зондирования Земли

Thermal fields of natural and anthropotechnogenic origin are an integral part of the urban habitat, which influences the functioning of its components, as well as determines the conditions of existence of living organisms including humans. Settlements act as areas of formation of extensive temperature anomalies, mainly positive ones, known as urban heat island. This phenomenon was discovered more than 200 years ago and is currently being investigated in detail. However, the study of smaller anomalies - neighbourhood-scaled and local - is also a subject of scientific and practical interest. These heterogeneities in the distribution of thermal energy are caused by the presence or functioning of individual objects, and therefore, on the one hand, have a direct impact on the state of the environment and human living conditions, and on the other hand, are a promising area for the development of environmental engineering and settlement rational arrangement. As part of the conducted research, the main patterns of spatial distribution of the Earth's surface temperature within the Rostov-on-Don city district were identified, as well as the areas of formation of anomalies of local and neighbourhood scale and objects and processes contributing to their formation were identified. The results and conclusions can be used for further study of ecological and geophysical features of urban landscapes, and also have an applied value in determining the direction and consequences of the impact of the advancement of specific types of urban development of the territory.

Emissivity of the Earth as a Cancer Predictor

Aim: The anticancer properties of locally applied infrared radiation are widely discussed in the literature. Earth's global emissivity, or the infrared radiation emitted by our planet, is inhomogeneous and varies based on the geophysical characteristics of the region where one resides. This study aimed to test the hypothesis: does local emissivity influence the prevalence of malignant diseases in a region. Materials and Methods: We performed planimetric comparison of two World maps: 1. NASA Spacecraft Map of Earth's Global Emissivity; 2. GLOBOCAN 2020 Global Cancer Data. For comparison we used “Image Compare” tool from Oxford Robotics Research Group. For the area measurements we used FreeMapsTools calculator. Results: The total assessed area was 127,750,000 square kilometers. The distribution according to emissivity was as follows: 107,050,000 km² of area with emissivity above 0.94 and 20,700,000 km² of area with emissivity below 0.94. The distribution according to cancer incidence was as follows: 28,150,000 km² of area with cancer incidence lower than 180 per 100,000 and 99,600,000 km² of area with cancer incidence more than 180 per 100,000. Cancer incidence was found to be statistically significantly associated with higher emissivity of the defined area (p-value < 0.0001). Conclusion: We found a significant association between areas of higher emissivity on our planet and higher cancer incidence. Our findings underscore the need to include environmental factors, in our case infrared radiation exposure, as potential predictor in the deployment of cancer predictive models, such as those involving machine learning and artificial intelligence.

An approach for predicting surface strong motion using borehole seismometers

South Korea has implemented borehole-type seismometers for reliable earthquake observations and earthquake early-warning systems, with approximately 85% of seismometers being replaced by borehole-type seismometers after the Gyeongju earthquake. Although these seismometers are more effective at detecting earthquakes owing to the reduced artificial ambient noise, they do not record surface-level shaking. Therefore, it is necessary to estimate ground surface shaking directly associated with potential damage when using borehole-type seismometers without surface sensors. This study investigated and compared various methods, including the stochastic point-source ground-motion model, transfer function based on ambient noise, and one-dimensional site response, to estimate horizontal seismograms of the ground surface. We assessed the accuracy of these methods by comparing the waveforms generated in event cases (magnitude from 2.5 to 5.8, with epicentral distances spanning 22 km–209 km) in terms of Fourier spectra, intensity, and spectral acceleration. Among the methods assessed, the transfer function approach, which does not account for the geophysical characteristics such as VS30, proved to be the most appropriate for correcting ground-surface effects.

Mapping Permafrost Variability and Degradation Using Seismic Surface Waves, Electrical Resistivity, and Temperature Sensing: A Case Study in Arctic Alaska

AbstractSubsurface processes significantly influence surface dynamics in permafrost regions, necessitating utilizing diverse geophysical methods to reliably constrain permafrost characteristics. This research uses multiple geophysical techniques to explore the spatial variability of permafrost in undisturbed tundra and its degradation in disturbed tundra in Utqiaġvik, Alaska. Here, we integrate multiple quantitative techniques, including multichannel analysis of surface waves (MASW), electrical resistivity tomography (ERT), and ground temperature sensing, to study heterogeneity in permafrost’s geophysical characteristics. MASW results reveal active layer shear wave velocities (Vs) between 240 and 370 m/s, and permafrost Vs between 450 and 1,700 m/s, typically showing a low‐high‐low velocity pattern. Additionally, we find an inverse relationship between in situ Vs and ground temperature measurements. The Vs profiles along with electrical resistivity profiles reveal cryostructures such as cryopeg and ice‐rich zones in the permafrost layer. The integrated results of MASW and ERT provide valuable information for characterizing permafrost heterogeneity and cryostructure. Corroboration of these geophysical observations with permafrost core samples’ stratigraphies and salinity measurements further validates these findings. This combination of geophysical and temperature sensing methods along with permafrost core sampling confirms a robust approach for assessing permafrost’s spatial variability in coastal environments. Our results also indicate that civil infrastructure systems such as gravel roads and pile foundations affect permafrost by thickening the active layer, lowering the Vs, and reducing heterogeneity. We show how the resulting Vs profiles can be used to estimate key parameters for designing buildings in permafrost regions and maintaining existing infrastructure in polar regions.

Chapter 3: The Origins and Evolution of Planetary Systems.

The materials that form the diverse chemicals and structures on Earth-from mountains to oceans and biological organisms-all originated in a universe dominated by hydrogen and helium. Over billions of years, the composition and structure of the galaxies and stars evolved, and the elements of life, CHONPS, were formed through nucleosynthesis in stellar cores. Climactic events such as supernovae and stellar collisions produced heavier elements and spread them throughout the cosmos, often to be incorporated into new, more metal-rich stars. Stars typically form in molecular clouds containing small amounts of dust through the collapse of a high-density core. The surrounding nebular material is then pulled into a protoplanetary disk, from which planets, moons, asteroids, and comets eventually accrete. During the accretion of planetary systems, turbulent mixing can expose matter to a variety of different thermal and radiative environments. Chemical and physical changes in planetary system materials occur before and throughout the process of accretion, though many factors such as distance from the star, impact history, and level of heating experienced combine to ultimately determine the final geophysical characteristics. In Earth's planetary system, called the Solar System, after the orbits of the planets had settled into their current configuration, large impacts became rare, and the composition of and relative positions of objects became largely fixed. Further evolution of the respective chemical and physical environments of the planets-geosphere, hydrosphere, and atmosphere-then became dependent on their local geochemistry, their atmospheric interactions with solar radiation, and smaller asteroid impacts. On Earth, the presence of land, air, and water, along with an abundance of important geophysical and geochemical phenomena, led to a habitable planet where conditions were right for life to thrive.

Participatory Analysis of Impacts of Agricultural Production Systems in a Watershed Depicting Southern Brazilian Agriculture

The objective of this study was to propose a multidimensional model capable of evaluating, in a participatory method, the pressures agricultural production systems cause to aquatic ecosystems. The model was structured with information compiled from scientific articles, doctoral theses, public documents, and field research performed with the participation of stakeholders through interviews, questionnaires, and group evaluations. The evaluation matrix combines seven criteria and twenty-five sub-criteria with different weights to evaluate two main aspects: (i) land occupation and soil management and (ii) agricultural waste production and disposal. The model was tested in 14 agricultural farms, representing four productive arrangements, in a large watershed (2400 km2) in southern Brazil. The geophysical characteristics of the site (18.3%), land use and occupation (28.2%), management practices (soil and water) (25.4%), manure and fertilizers (12.6%), pesticides (14.1%), agricultural waste and discards (1.4%) were the criteria and their respective weights used in the structure of the proposed evaluation model. The evaluation showed that the combination of the fragility of cultivated environments and the absence of conservation practices represented the greatest risks (72.9%) to maintaining the sound environmental conditions of aquatic ecosystems. For future research, it is recommended that a cost-effectiveness analysis be carried out to evaluate environmental conflicts.

An assessment of seismicity and near surface geophysical characteristics of potential solid waste landfill sites in the Eastern Black Sea Region of Türkiye.

This study aimed to assess the suitability of the potential solid waste landfill sites in seven provinces (Samsun, Ordu, Giresun, Trabzon, Gümüşhane, Bayburt and Artvin) in the Eastern Blacksea Region of Türkiye. The earthquake hazard analysis for two major earthquakes which occurred in the region was first carried out. Then, the geophysical methods including seismic refraction tomography (SRT), electrical resistivity tomography (ERT) and Multichannel Analysis of Surface Waves (MASW) were conducted to find out the structural and physical properties of the subsurface which include the layering, soil classification based on VS30 and the groundwater content at 25 locations of 13 in target provinces. The integrated interpretation of whole data sets demonstrates that Işıktepe, Esence, Çamburnu and Kazantaş which are characterized by VP > 1200m/s, VS30 ≥ 400m/s, ρ > 70 Ohm-m, low earthquake hazard and seismicity are more suitable among others. Vezirköprü, Şebinkarahisar, Yenice, Bayburt-Center, Balkaynak and Murgul will be suitable after a geotechnical reclamation due to moderate seismic velocities and electrical resistivity which are 900 < VP ≤ 1200m/s, 200 < VS30 < 400m/s and 10 < ρ ≤ 70 Ohm-m representing stiff and wet soils. In addition, Bafra, Ağalık and Ovacık were considered to be unsuitable due to the presence of thick, water-saturated soft soil and extremely weathered rocks. Finally, this study shows that the joint interpretation of seismicity and geophysical data in potential waste landfill sites, extremely important for the planning and development of a city, can provide the valuable information which will enable to prevent possible deformations, environmental problems and economic losses after waste landfill.

An integrated methodological approach to substantiating the properties of high-viscosity oils using the example of the Karazhanbas oil field

Rationale: A characteristic feature of the modern stage of oil field development is the increase in the share of hard-to-recover oils, which mainly include heavy, highly viscous oils. This is due to changes in the structure of oil, an increase in the water cut of produced oil, geological and geophysical characteristics and conditions of oil occurrence that are unfavorable for extraction. The reserves of such oil significantly exceed the reserves of light and low-viscosity oil and, according to experts, they amount to at least 1 trillion tons. In industrialized countries they are considered not so much as a reserve for oil production, but as the main basis for its development in the coming years. The peculiarity of heavy oil is explained by its composition and PVT properties, which have a fairly serious impact on production.&#x0D; Target: Application of an integrated approach to substantiating the properties of high-viscosity oil and tools for mathematical modeling of the phase state of fluids in order to increase the reliability of reserve calculations and the efficiency of the oil field development.&#x0D; Materials and methods: The scientific work was based on the results of geochemical studies (fingerprinting and biomarker analysis), experimental data from rheological studies and the results of modeling the phase state of fluids.&#x0D; Results: It is proposed to use an integrated approach to data interpretation and compositional calculations, which make it possible to narrow the range of uncertainty and explain the huge variation in the values of physicochemical parameters across samples.&#x0D; Conclusion: An integrated approach to analyzing the results of PVT experiments, together with geological and field data and the results of geochemical studies, provides high-quality data that allows you to make strategic decisions on the oil field development, conduct accurate resource assessments and predict hydrocarbon production.

An updated 3D crustal velocity model in Cyprus by non-linear traveltime tomography

We have used >6000 regional earthquakes in the broader Cyprus island area, with 100,000+ P and S-phases recorded by 26 local seismological stations to obtain a 3D velocity model for the Cyprus area using a non-linear seismic tomography approach. Due to the limited aperture of the recording network, the tomographic model mainly recovers the dominant geophysical features of the upper crust of the Cyprus island. The obtained results reveal new information on the 3D structure of the Troodos ophiolithic complex, identifying a high velocity anomaly that coincides with the NW-SE trending ophiolitic units of the Troodos mountain. Furthermore, they clearly show that the anomaly associated with the ophiolite zone of Troodos is well preserved up to a depth of at least 10 Km, dipping towards the Northeast. The Mesaoria basin in central Cyprus is recognized as a large low-velocity feature, with the results suggesting a significant thickness of the basin, exceeding 5 km. A similar low-velocity pattern can be observed for the Circum Troodos formations (Pakhna and Lefkara) to the southwest of the Troodos mountain, while the Kyrenia range is not associated with a crustal velocity anomaly. To assess the reliability of the results we have conducted checkerboard resolution tests, which suggest that the uppermost crustal features are well reconstructed, while for larger depths (>10 km) we cannot recover mid-crustal anomalies due to the insufficient traveltime data coverage and quality (e.g., traveltime picking errors).

Is heat stress a growing problem for dairy cattle husbandry in the temperate regions? A case study of Baden-Württemberg in Germany.

Heat stress with measurable effects in dairy cattle is a growing concern in temperate regions. Heat stress in temperate regions differs between environments with different geophysical characteristics. Microclimates specific to each environment were found to greatly impact at what level heat stress occurs and will occur in the future. The landlocked state of Baden-Württemberg, Germany, provides several different environments, hence, a good case-study. Temperature-Humidity Index (THI) from 17 weather stations for the years 2003 to 2022 was calculated and milking yields from 22 farms for the years 2017 to 2022 were collected. The occurrences and evolving patterns of heat stress were analyzed with the use of a THI, and the effect of heat stress on milk yield was analyzed based on milking records from Automated Milking Systems. Daily average THI was calculated using hourly readings of relative humidity and ambient temperature, disregarding solar radiation and wind, as all animals were permanently stabled. Based on studies conducted in Baden-Württemberg and neighboring regions, cited ahead in the section of THI, THI = 60 was the threshold for heat stress occurrence. Findings show that the heat stress period varied between stations from 64 to 120 d with THI ≥ 60 in a year. This aligns with yearly and summer averages, also steadily increasing from May to September. The length of the heat stress period was found to increase 1 extra day every year. Extreme weather events such as heat waves did not increase the heat stress period of that year in length but increased the average THI. Milk yield was found to be significantly (α = 0.05) different between counties grouped into different zones according to heat stress severity and rate of increase in daily average THI. Future attempts at managing heat stress on dairy cattle farms in the temperate regions should account for microclimate, as geographical proximity does not mean that the increase in heat stress severity will be the same in the 2 neighboring areas.

ENVIRONMENTAL GEO-INFORMATIONAL MONITORING SYSTEM FOR THE CIVIL AND FIRE SAFETY SERVICES OF UKRAINE

Background.The purpose of the work is the development of a new ecological and geo-informational system for monitoring emergency situations, which allows quick predicting the consequences of various natural and man-made hazards at the stage of preventing their occurrence. This applies to possible cases of destruction on territories where there is a threat of flooding and, accordingly, the protection of coasts, structures, roads on mountain slopes, bridges, tunnels and dams built on soils with certain geological and geophysical characteristics, as well as the occurrence and spread of fires and pollution of air, water and soil with harmful substances associated with them. Methods. To implement the methods, available and purchased licensed software is used, creating convenient algorithms for solving practical tasks of civil protection. Information processing based on the used software packages that allow quickly processing large amounts of information, reducing the level of poor processing and data distortion. Results. An ecological and geo-informational monitoring system has been developed, designed to ensure the coordination of actions of civil and fire protection services in order to increase the efficiency of responding to emergency situations of natural and manmade origin. By conducting experiments, model results were obtained, which make possible to theoretically calculate and determine the critical permissible stress-deformed states of the soil massif in the area of engineering structures, bridge structures, to warn about the possible destruction of the massif due to excess stress and deformation under the action of loads. Proposed localization of fire-hazardous zones based on satellite data. As part of the developed system for space monitoring of forest fires, satellite information is used, in particular, the AVHRR radiometer of the Terra satellite. On its basis, a temperature map of the regions of Ukraine was formed. Conclusions. The geo-informational monitoring system was created to prevent the risks of emergency situations (including the destruction of slopes, fires, etc.) using software products, creating databases for mapping potentially dangerous objects. Its application will make it possible to assess the consequences of possible emergency situations of a natural and man-made nature and minimize their negative impact on the environment. The developed geo-information system can be used to coordinate the actions of civil and fire protection services, as well as increase the efficiency of emergency and rescue measures.

Geophysical, geotechnical, and vegetation characteristics in landslide areas in Pujon and Ngantang, Malang Regency, East Java

One of the efforts to manage the risk of ground movement is to identify landslide-prone area characteristics. This study aimed to investigate the geophysical, geotechnical, and vegetation characteristics of landslide and non-landslide areas. This study adopted the resistivity geoelectric method to identify the type and structure of subsurface materials in landslide and non-landslide regions in Pujon and Ngantang, Malang Regency. Measurements in this study were done in four locations. Each geoelectric measurement path at each location was determined to be 100 m long. The electrodes were spaced apart by 10 m for measurements between the current electrode and the potential electrode. The dipole-dipole configuration of the geoelectric survey trajectory is determined based on the former landslide event to predict underground material. In addition, an investigation of geological, geotechnical, and vegetation characteristics was carried out. The results showed that the geophysical, soil, and vegetation characteristics of the landslide and non-landslide slopes were similar. The geophysical characteristics of the soil in all study locations indicate the presence of a slipping surface, which makes the land prone to landslides. The slipping plane was formed due to differences in the types of rocks between the surface and deep layers. The existence of vegetation has an important role in landslide management. Non-landslide areas tended to have denser tree vegetation and a higher number of shrub species.

Holocene and postglacial lake sedimentation in the central part of the Karelian Isthmus as an example of Lake Krasnoye in the Leningrad region

This paper deals with the issue of changing the conditions of the geographical environment in the postglacial and Holocene in the central part of the Karelian Isthmus. Toward paleogeographic reconstruction, a survey of the sediments of the bottom of Lake Krasnoye (Leningrad Oblast, Russian Federation) was conducted, since the lake deposits represent a reliable source of information about natural events from the past. A large amount of data obtained by X-ray fluorescence analysis of the core sample was analyzed, a lithostratigraphic description of the sediments was carried out and geophysical characteristics of the bottom sediments were interpreted. They were divided into several units that differed in the number of properties and reflected different sedimentation conditions. In the reconstruction of the past natural environment, special attention is paid to paleoclimatic and paleosedimentological issues.

Linking the Neoproterozoic to Early Paleozoic Belts Bordering the West African and Amazonian Cratons: Review and New Hypothesis

Correlations between the Neoproterozoic belts surrounding the West African Craton and northern Brazilian cratons have long been a subject of interest and controversies. Due to the splitting of African and South American continents by the Atlantic oceanic domains, no direct links are preserved, requiring relying on various geological or geophysical characteristics to propose such correlations. In addition to the opening of the Atlantic oceanic domains, another difficulty arises from the covering of northern Brazilian belts by upper Paleozoic and Mesozoic basins, making these correlations speculative. Here, we propose new correlations based on the comparison between African and Brazilian belts. Recently, new geochronological and geodynamical data obtained in West Africa have evidenced four orogens in the Neoproterozoic belts of the western margin of the West Africa Craton, while the belts on the eastern side underwent only one orogeny. Similarities with the Pan-African I (900–650 Ma) and with the Pan-African II (650–480 Ma) orogenic events have been evidenced in the western Brazilian belts (Araguay and Paraguay). The first two orogens on the western margin (Pan-African I and Pan-African II) can thus be extended to the western Brazilian belts and can be considered as parts of a single geodynamic system running from the Mauritania to the Paraguay including the “Gurupi rift” as an aulacogen connected to the NNW-SSE Panafrican I and II oceanic domains. Consequently, the eastern Brazilian belt should rather be linked the Eastern Trans-Saharan belts.

Investigation of Ambient Seismic Noise in Different Region of Georgia

Georgia, like the whole South Caucasus, is a tectonically and structurally complex region. It is one of the active segments of the Alpine-Himalayan belt, therefore it is important to assess the seismic hazard for Georgia. At the regional scale, this assessment is evaluated by applying probabilistic seismic hazard analysis that identifies the annual probability of exceedance of various ground motion levels defined in terms of selected ground motion intensity measures, such as PGA or spectral accelerations (SA) corresponding to various return periods related to possible future earthquake scenarios for a site represented by soil classes A according to EC8, Euro-code 8-EN 1998-1 (1998). At the local scale, seismic hazard assessment is made by analyzing the geological, geomorphological, geotechnical and geophysical characteristics of the site, as it is well established that the incoming seismic motion can change in amplitude, frequency, and duration due the site-specific local characteristics. That is the subject of micro-zonation investigation. Site – specific local characteristics are presented by the following parameters: Dominant frequency, Vs,30 (average shear-wave velocity to a depth of 30 meters) and amplification factor. In this work, we presented results of geophysical survey assessing local site conditions by dominant frequency that allows identification of similar seismic response areas. For this purpose, seismic noise records have been used first time in Georgia.

GIS modeling to investigate environmental change and degradation in Kohima district, North East Hill (NEH) region of India.

As a part of the Himalayan mountains, the North East Hill (NEH) region of India is geophysically dynamic and seismotectonically active since its formation about 55 million years ago with a head-on collision of the Indian plate and the Eurasian plate. The region still has been underthrusting at a rate of 4.5-5cm/year causing the reshaping and changing of its geophysical characteristics (geology, geomorphology, relief, slope gradient, drainage system, etc.), whereas anthropogenic activities, particularly shifting cultivation and technological intervention, have caused changes or degradation of the ecological environment (air, land, water, vegetation, crop pattern, climate, wildlife, etc.). Addressing this burning geoecological problem, a geospatial technology-based case study from the Kohima district of Nagaland in the North East Hill region of India is presented here. Through the development and integration of multiple GIS modules, this reconnaissance study suggests that continuous seismic activities (about 27 seismic events/year) along tectonic faults, thrusts, and lithological shear zones have been reshaping and changing the geophysical environment, whereas the ecological environment has been changing or degrading due to decreasing natural landscape and habitats (forest area, water bodies, and shrubs) at an annual rate of 5.91 km2 (0.60%), increasing built-up area, agricultural land, and wasteland at an annual rate of 2.73 km2 (0.28%), 2.69 km2 (0.27%), and 0.49 km2 (0.05%) respectively. Results also suggest that environmental degradation results in accelerated trends of climate change (rising temperature at the rate of 0.13°C/year, decreasing annual rainy days at the rate of 2days/year, decreasing annual rainfall at the rate of 9.55cm/year, mounting climatic zones at the rate of 175m/year) and its adverse impacts (increasing extreme rainfall events at the rate of 3 events/year and causing cloud burst, erosion, landslides, and floods) in the region.

Heat Flow Prediction in Songliao Basin Based on Deep Neural Network

The heat flow is the key data for accurately predicting the contribution of underground heat, but due to the high cost of measurement, the spatial difference is huge, and the heat flow information in some areas is little known. This paper uses deep neural network technology to perform machine learning on a large number of relevant geological and geophysical features and heat flow measurements on a global scale. In addition, the model uncertainty quantification process is introduced, and the reliability of the prediction results is discussed based on the global sensitivity analysis and correlation calculation of the deep learning method. Finally, for the distribution map of heat flow and absolute difference in the Songliao Basin in the study area, the measured data error is less than 11%, and the predicted absolute difference is less than ±20 mW/m2. The results prove the accuracy of the method and the abnormal high heat flow in the central region of the basin. The existence of, further combined with the results of geophysical surveys, provides evidence for the analysis of regional thermal causes.

The Comprehensive Detection Technology for Embankment Leakage

Based on the study of geophysical characteristics of embankment leakage, this paper adopts Dual coil transient electromagnetic (Dual TEM) and parallel direct current resistivity method(PDC) to carry out comprehensive detection. Dual TEM can greatly reduce the shallow blind area of conventional transient electromagnetic and improve the resolution of induced signal, PDC method can efficiently collect signals of all electrical arrange and spontaneous potential signals, By using the cross-correlation processing technology between spontaneous potential and resistivity data. we quickly eliminate the false abnormal influence of low resistivity in embankment, it is a good application in the detection of Paihe embankment leakage in Hefei, Anhui Province in 2020.

Ancient silicic volcanism and incipient rift propagation during Gondwana breakup; geophysical insights from the Bumbeni ridge, South Africa

A detailed understanding of the association between magmatism and rift initiation is key to defining the prevailing tectonic conditions active during the initial break-up of Gondwana. The Bumbeni Complex in northern KwaZulu-Natal, South Africa represents an early Cretaceous silicic volcanic centre exposed at the southwestern termination of a linear zone of magnetic anomalies which are buried beneath sedimentary cover. Newly acquired high resolution aeromagnetic data combined with legacy seismic and borehole data is analysed to define the structural architecture of the basement beneath the Zululand Basin in northern KwaZulu-Natal. Multiple prominent positive and negative anomalies ranging from −200 nT to +300 nT based on International Geomagnetic Reference Field (IGRF) and corrected Reduced to Pole (RTP) data are resolved and form a distinct geophysical lineament. Geophysical and borehole core data indicate that the lineament represents a chain of silicic central volcanoes developed as a ridge feature, the Bumbeni Ridge, along the axial zone of an incipient rift structure. Detailed geological mapping and high resolution geophysical data are analysed and compared with analogous contemporary continental rift environments, as well as published data within the adjacent offshore Northern Natal Valley. Results are presented which propose a continental rift evolutionary model for Gondwana breakup in the Zululand Basin in northern KwaZulu-Natal.

Specific Features of the Land-Sea Contrast of Cloud Liquid Water Path in Northern Europe as Obtained from the Observations by the SEVIRI Instrument: Artefacts or Reality?

Liquid water path (LWP) is one of the most important cloud parameters and is crucial for global and regional climate modelling, weather forecasting, and modelling of the hydrological cycle and interactions between different components of the climate system: the atmosphere, the hydrosphere, and the land surface. Space-borne observations by the SEVIRI instrument have already provided evidence of the systematic difference between the cloud LWP values derived over the land surface in Northern Europe and those derived over the Baltic Sea and major lakes during both cold and warm seasons. In the present study, the analysis of this LWP land-sea contrast for the period 2011–2017 reveals specific temporal and spatial variations, which, in some cases, seem to be artefacts rather than of natural origin. The geographical objects of investigation are water bodies and water areas located in Northern Europe that differ in size and other geophysical characteristics: the Gulf of Finland and the Gulf of Riga in the Baltic Sea and large and small lakes in the neighbouring region. The analysis of intra-seasonal features has detected anomalous conditions in the Gulf of Riga and the Gulf of Finland, which show up as very low values of the LWP land-sea contrast in August with respect to the values in June and July every year within the considered time period. This anomaly is likely an artefact caused by the LWP retrieval algorithm since the transition from large LWP contrast to very low contrast occurs sharply, synchronically, and at a certain date every year at different places in the Baltic Sea.