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This study presents new maps of the topographic and geophysical setting and seismicity in the region of the Gulf of Panama. The spatial analysis is based on the comparative analysis of the datasets on geoid, free-air gravity anomaly, topography and earthquakes. The cartographic framework is developed using the Generic Mapping Tools (GMT) scripting toolset. Seismic activity in the Central America is high due to the complex geologic setting, tectonic activity and lithosphere plate subduction. The data include the Earth Gravitational Model (EGM2008), the General Bathymetric Chart of the Oceans (GEBCO) and gravity grids. The seismicity data were collected from the Incorporated Research Institutions for Seismology (IRIS) catalogue on 1970-2021. The variations in data were compared to analyse correlations between the geophysical, seismic and topographic parameters. Free-air gravity, geoid and topographic data derived from the high-resolution datasets were used to investigate their effects on the main seismic sources in the region. The comparison of the maps showed that the distribution of the shallow earthquakes in the Pacific segment of Panama coincides with negative free-air anomalies and lower geoid values. The results revealed high values of geoid in the high mountainous regions of Panama (Cordilliera de Talamanca, southern coast of Peninsula de Azuero and eastern Panama, 77.5-78.5°W), which correspond to the topographic roughness in the highlands. Negative values of geoid are found over the Caribbean Sea basin (−4 to 0 m). The analyses of seismicity showed 1740 earthquake events varying by magnitudes from 2.9 to 7.8 at the depths up to 225 m (near the west coast of Colombia). A high concentration of the earthquakes is in the western region of the Panama's shelf waters (~82-83.5°W), and on the border with Colombia (~77-78.5°W). High gravity anomalies (over 220 mGal) are found in the mountainous regions which match the geodynamic processes associated with the Earth str, SCOPUS: ar.j, info:eu-repo/semantics/published

Evaluating the subground properties during the initial stage of a construction of building is important in order to estimate the suitability of soil quality to the technical requirements of bearing capacity, resistance to stress, and strength. This study presented the evaluation of the geotechnical properties of soil intended for the construction of Max IV facility of Lund University, performed in fieldwork and laboratory. The in situ methods included drilling boreholes, core sampling and assessment, crosshole measurements, and borehole logging. The laboratory-based measurements were performed at Swedish Geotechnical Institute and combined seismic measurements of drill cores, determination of the uniaxial compressive strength (UCS), and examination of material property: sieve analysis and natural moisture content. UCS was evaluated with regard to velocities of elastic P-waves. The synchronous light test by X-ray diffraction was performed for qualitative analysis of mineral composition of samples. The study applied integrated approach of the diverse geophysical methods to solve practical tasks on the evaluation of foundation strength and geotechnical parameters. This study demonstrated the benefits of integrated seismic and geophysical methods applied to soil exploration in civil engineering for testing quality of foundation materials., SCOPUS: ar.j, info:eu-repo/semantics/published

Archived seismograms recorded in the 20th century present a valuable source of information for monitoring earthquake activity. However, old data, which are only available as scanned paper-based images should be digitised and converted from raster to vector format prior to reuse for geophysical modelling. Seismograms have special characteristics and specific features recorded by a seismometer and encrypted in the images: signal trace lines, minute time gaps, timing and wave amplitudes. This information should be recognised and interpreted automatically when processing archives of seismograms containing large collections of data. The objective was to automatically digitise historical seismograms obtained from the archives of the Royal Observatory of Belgium (ROB). The images were originally recorded by the Galitzine seismometer in 1954 in Uccle seismic station, Belgium. A dataset included 145 TIFF images which required automatic approach of data processing. Software for digitising seismograms are limited and many have disadvantages. We applied the DigitSeis for machine-based vectorisation and reported here a full workflow of data processing. This included pattern recognition, classification, digitising, corrections and converting TIFFs to the digital vector format. The generated contours of signals were presented as time series and converted into digital format (mat files) which indicated information on ground motion signals contained in analog seismograms. We performed the quality control of the digitised traces in Python to evaluate the discriminating functionality of seismic signals by DigitSeis. We shown a robust approach of DigitSeis as a powerful toolset for processing analog seismic signals. The graphical visualisation of signal traces and analysis of the performed vectorisation results shown that the algorithms of data processing performed accurately and can be recommended in similar applications of seismic signal processing in future related works in geophysi, SCOPUS: ar.j, info:eu-repo/semantics/published

This paper presents a cartographic framework based on algorithms of GMT codes for mapping seismically active areas in Venezuela. The data included raster grids from GEBCO, EGM- 2008, and vector geological layers from the USGS. The data were iteratively processed in the console of GMT, converted by GDAL, formatted, and mapped for geophysical data visualisation; the QGIS was applied for geological mapping. We analyzed 2000 samples of the earthquake events obtained from the IRIS seismic database with a 25-year time span (1997–2021) in order to map the seismicity. The approach to linking geological, topographic, and geophysical data using GMT scripts aimed to map correlations among the geophysical phenomena, tectonic processes, geological setting, seismicity, and earthquakes. The practical application of the GMT scripts consists in automated mapping for the visualization of geological risks and hazards in the mountainous region of the Venezuelan Andes. The proposed method integrates the approach of GMT scripts with state-of-the-art GIS techniques, which demonstrated its effectiveness as a tool for mapping spatial datasets and rapid data processing in an iterative regime. In this context, using GMT and GIS to find similarities between the regional earthquake distribution and the geological and topographic setting is essential for hazard risk assessment. This study can serve as a basis for predictive seismic analysis in geologically vulnerable regions of Venezuela. In addition to a technical demonstration of GMT algorithms, this study also contributes to geological and geophysical mapping and seismic hazard assessments in South America. We present the full scripts used for mapping in a GitHub repository., SCOPUS: ar.j, info:eu-repo/semantics/published

Before digital recordings became available in the 1970s, the ground motion was recorded using ink on white paper, scratching black-smoked paper, or light on photographic paper. While those analog seismic records offer unique continuous observations from the last century, most of them are now stacked and archived in boxes and potentially exposed to physical decay and permanent loss. To preserve those records and ultimately subject them to modern methods of analysis, it is time-sensitive to scan and digitize them. Here, we worked on a method for automatic digitization of paper seismograms using image processing and machine learning to extract microseismic ground-motion periods and amplitudes. We implemented the method on legacy data recorded at the Royal Observatory of Belgium to extract power spectral densities for major storms during the last century, which are compared with modeled microseisms levels computed using a numerical ocean wave model. This further shows how digitizing analog seismograms does not only preserve the scientific legacy but also makes new research possible by bringing analog data to the digital age., info:eu-repo/semantics/published

Erdbeben gehören zu den zerstörerischsten Naturgefahren auf diesem Planeten. Obwohl Erdbeben seit Jahrtausenden dokumentiert sing, bleiben viele Fragen zu Erdbeben unbeantwortet. Eine Frage ist die Vorhersagbarkeit von Brüchen: Inwieweit ist es möglich, die endgültige Größe eines Bebens zu bestimmen, bevor der zugrundeliegende Bruchprozess endet? Diese Frage ist zentral für Frühwarnsysteme. Die bisherigen Forschungsergebnisse zur Vorhersagbarkeit von Brüchen sind widersprüchlich. Die Menge an verfügbaren Daten für Erdbebenforschung wächst exponentiell und hat den Tera- bis Petabyte-Bereich erreicht. Während viele klassische Methoden, basierend auf manuellen Datenauswertungen, hier ihre Grenzen erreichen, ermöglichen diese Datenmengen den Einsatz hochparametrischer Modelle und datengetriebener Analysen. Insbesondere ermöglichen sie den Einsatz von maschinellem Lernen und deep learning. Diese Doktorarbeit befasst sich mit der Entwicklung von Methoden des maschinellen Lernens zur Untersuchung zur Erbebenanalyse. Wir untersuchen zuerst die Kalibrierung einer hochpräzisen Magnitudenskala in einem post hoc Scenario. Nachfolgend befassen wir uns mit Echtzeitanalyse von Erdbeben mittels deep learning. Wir präsentieren TEAM, eine Methode zur Frühwarnung. Auf TEAM aufbauend entwickeln wir TEAM-LM zur Echtzeitschätzung von Lokation und Magnitude eines Erdbebens. Im letzten Schritt untersuchen wir die Vorhersagbarkeit von Brüchen mittels TEAM-LM anhand eines Datensatzes von teleseismischen P-Wellen-Ankünften. Dieser Analyse stellen wir eine Untersuchung von Quellfunktionen großer Erdbeben gegenüber. Unsere Untersuchung zeigt, dass die Brüche großer Beben erst vorhersagbar sind, nachdem die Hälfte des Bebens vergangen ist. Selbst dann können weitere Subbrüche nicht vorhergesagt werden. Nichtsdestotrotz zeigen die hier entwickelten Methoden, dass deep learning die Echtzeitanalyse von Erdbeben wesentlich verbessert., Earthquakes are among the largest and most destructive natural hazards known to humankind. While records of earthquakes date back millennia, many questions about their nature remain open. One question is termed rupture predictability: to what extent is it possible to foresee the final size of an earthquake while it is still ongoing? This question is integral to earthquake early warning systems. Still, research on this question so far has reached contradictory conclusions. The amount of data available for earthquake research has grown exponentially during the last decades reaching now tera- to petabyte scale. This wealth of data, while making manual inspection infeasible, allows for data-driven analysis and complex models with high numbers of parameters, including machine and deep learning techniques. In seismology, deep learning already led to considerable improvements upon previous methods for many analysis tasks, but the application is still in its infancy. In this thesis, we develop machine learning methods for the study of rupture predictability and earthquake early warning. We first study the calibration of a high-confidence magnitude scale in a post hoc scenario. Subsequently, we focus on real-time estimation models based on deep learning and build the TEAM model for early warning. Based on TEAM, we develop TEAM-LM, a model for real-time location and magnitude estimation. In the last step, we use TEAM-LM to study rupture predictability. We complement this analysis with results obtained from a deep learning model based on moment rate functions. Our analysis shows that earthquake ruptures are not predictable early on, but only after their peak moment release, after approximately half of their duration. Even then, potential further asperities can not be foreseen. While this thesis finds no rupture predictability, the methods developed within this work demonstrate how deep learning methods make a high-quality real-time assessment of earthquakes practically feasibl

This research describes a script-based method of Generic Mapping Tools (GMT) for mapping the seismicity, geophysics, geology and topography of Ecuador. The advances of GMT include the following points: (1) automation of workflow; (2) refined aesthetics of graphics; (3) speed console-based mapping; (4) multi-format data handling; (5) advanced syntax. An explanation of scripting with the examples of code snippets is provided. The results present six new maps of Ecuador. The distribution of geophysical phenomena and seismicity is compared to the terrain elevation, showing remarkable correlations with the topography and geoid. The data demonstrated low values in the depression of the Andes, the Gulf of Guayaquil, and the Peru-Chile Trench. The peaks in gravity are representative for the Andean topography. Local decreases in gravity correspond to the depressions in the coastal shelf and the Gulf of Guayaquil. The increase in seismicity is detected along the tectonically active areas. The GMT is appropriate to the geological risk assessment of Ecuador., SCOPUS: ar.j, info:eu-repo/semantics/published

This paper presents a GMT scripting technique for mapping seismic moment tensor solutions. The underlying geophysical properties and settings of the Philippine Sea Plate (PSP) situated on the margins of the Pacific Ocean are analysed. Active volcanism and high seismicity of this region located along the margins of the Philippine Sea Basin (PSB) results in a series of earthquake events caused by geodynamic processes of tectonic plate subduction. The proposed console-based framework of cartographic workflow is designed to perform mapping of the earthquake events using Generic Mapping Tools (GMT) modules, to analyse seismic setting through visualisation of the geophysical dataset. The materials include General Bathymetric Chart of the Oceans (GEBCO), Centroid Moment Tensor (CMT) and International Seismological Centre (ISC) seismic data. Technically, the algorithm of mapping by GMT consists in a consecutive use of modules used in a script run from a command line: ’psmeca’, ’psvelo’, ’img2grd’, ’grdtrack’, ’grdimage’. The GMT functionality is illustrated by the key snippets of code. The path to the full codes is provided with a link to the author’s GitHub repository for technical repeatability. Furthermore, the algorithm of GMT enabled to visualise CMT solutions for shallow depth earthquakes of Mw ¡10 along the PSB margins from 1976 to 2010. Thus, the paper also demonstrated and presented the performance of the GMT on a geophysical dataset that features complete earthquakes data along the zone of tectonic plate subduction from the Global CMT Project. In both technical and geophysical cases, this approach of GMT-based mapping presents cartographic workflow better than state-of-the-art traditional GIS programs through increased automation of the cartographic workflow. The study contributed to the development of methods of geophysical and seismic mapping using GMT scripting toolset by visualising focal mechanisms and seismic moment tensor solutions., SCOPUS: ar.j, info:eu-repo/semantics/published

Evaluating soil strength by geophysical methods using P-waves was undertaken in this study to assess the effects of changed binder ratios on stabilisation and compression characteristics. The materials included dredged sediments collected in the seabed of Timrå region, north Sweden. The Portland cement (Basement CEM II / A-V, SS EN 197-1) and Ground Granulated Blast Furnace Slag (GGBFS) were used as stabilisers. The experiments were performed on behalf of the Svenska Cellulosa Aktiebolaget (SCA) Biorefinery Östrand AB pulp mill. Quantity of binder included 150, 120 and 100 kg. The properties of soil were evaluated after 28, 42, 43, 70, 71 and 85 days of curing using applied geophysical methods of measuring the travel time of primary wave propagation. The P-waves were determined to evaluate the strength of stabilised soils. The results demonstrated variation of P-waves velocity depending on stabilising agent and curing time in various ratios: Low water / High binder (LW HB), High water / Low binder (HW LB) and percentage of agents (CEM II / A-V/GGBFS) as 30%/70%, 50%/50% and 70%/30%. The compression characteristics of soils were assessed using Uniaxial Compressive Strength (UCS). The P-wave velocities were higher for samples stabilized with LW HB compared to those with HW LB. The primary wave propagation increased over curing time for all stabilized mixes along with the increased UCS, which proves a tight correlation with the increased strength of soil solidified by the agents. Increased water ratio gives a lower strength by maintained amount of binder and vice versa., SCOPUS: ar.j, info:eu-repo/semantics/published

Geophysical data from open sources are widely used as support of integrated analysis in regional geologic studies in seismically active areas, such as Mexico. High seismicity with repetitive earthquakes occurs in areas of the subduction zones formed during the tectonic evolution and correlates with geophysical anomalous fields. This paper investigates the correspondence between the geophysical, topographic and seismic setting of Mexico using Generic Mapping Tools (GMT) scripting toolset for data processing. The approach for automated mapping using GMT console and shell scripts is presented as an advanced cartographic method aimed to get insights into in the geology and geophysics of Mexico. The data were obtained from open source high-resolution datasets: GEBCO, EGM-2008, satellite-derived gravity, EMAG2 magnetic anomaly and IRIS seismic database. The correspondence between the geological and geophysical data of Mexico has been verified through the comparison between the thematic maps, regional distribution of gravity anomalies and locations of earthquakes. Seven new maps are performed on geologic, geophysical, topographic and seismic data. Seismic mapping is presented for the period of 2007-2021 demonstrating events with magnitude from 1.5 to 7.2. The impact of tectonic processes that formed Middle American Trench and active Trans-Mexican Volcanic Belt on high regional seismicity with intensive earthquakes is explored. The study finds that GMT is an effective tool for high-quality mapping and cartographic analysis. The IRIS data can be used for geologic analysis of Mexico., Dados geofísicos de fontes abertas são amplamente usados como suporte de análise integrada em estudos geológicos regionais em áreas sismicamente ativas, como o México. Alta sismicidade com terremotos repetitivos ocorre em áreas das zonas de subducção formadas durante a evolução tectônica e se correlaciona com campos anômalos geofísicos. Este artigo investiga a correspondência entre o cenário geofísico, topográfico e sísmico do México usando o conjunto de ferramentas de script Generic Mapping Tools (GMT) para processamento de dados. A abordagem para mapeamento automatizado usando o GMT e scripts de shell é apresentada como um método cartográfico avançado com o objetivo de obter insights sobre a geologia e a geofísica do México. Os dados foram obtidos de conjuntos de dados de alta resolução de código aberto: GEBCO, EGM-2008, gravidade derivada de satélite, anomalia magnética EMAG2 e banco de dados sísmico IRIS. A correspondência entre os dados geológicos e geofísicos do México foi verificada através da comparação entre os mapas temáticos, distribuição regional de anomalias gravitacionais e localizações de terremotos. Sete novos mapas são realizados em dados geológicos, geofísicos, topográficos e sísmicos. O mapeamento sísmico é apresentado para o período de 2007-2021 demonstrando eventos com magnitude de 1,5 a 7,2. O impacto dos processos tectônicos que formaram a trincheira da América Central e o cinturão vulcânico transmexicano ativo na alta sismicidade regional com terremotos intensos é explorado. O estudo concluiu que o GMT é uma ferramenta eficaz para mapeamento e análise cartográfica de alta qualidade. Os dados IRIS podem ser usados para análises geológicas do México., info:eu-repo/semantics/published

Integrated mapping is essential in geological studies to assess risks of earthquake hazards. Cartographic techniques have become a commonplace approach to visualizing data in the continuous geologic and geophysical fields. However, traditional GIS mapping is a manual process with a time-consuming workflow that can lead to mistakes and misinterpretation of data. This study applied two mapping approaches to address this problem: Generic Mapping Tools (GMT) used for automated cartographic workflow employing scripts and QGIS used for traditional geologic mapping. The study area includes Ethiopia, notable for its complex geologic setting. The study aimed to analyse the relationships between the geophysical, geological, topographic and seismic setting of the country by presenting six new thematic maps:1 topography based on the GEBCO/SRTM15+ high-resolution grid;2 geological units with consistent lithology and age from the USGS database;3 geological provinces with major Amhara Plateau and Somali Province using USGS data;4 geoid based on the Earth Gravitational Model 2008 (EGM-2008) grid;5 free-air gravity anomaly model using satellite-based remote sensing data;6 seismicity showing earthquakes and volcanos from 05/03/1990 to 27/11/2020.The comparison of the topography, seismicity, geophysics and surface geology of the Afar Depression and the Great Rift Valley was based partly on extant literature on the geologic setting of Ethiopia which primarily focuses upon discussing tectonic processes that took place in the East African Rift System in the past. The current study contributes to the previous research and increases cartographic data on the geology and geophysics of Ethiopia. The outcomes can be implemented in similar regional projects in Ethiopia for geophysical and geological monitoring., SCOPUS: ar.j, info:eu-repo/semantics/published

Detailed mapping based on the high-resolution grids, such as GEBCO, ETOPO1, GlobSed, EGM-2008 is crucial for various domains of Earth sciences: geophysics, glaciology, Quaternary, sedimentology, geology, environmental science, geomorphology, etc. The study presented a GMT-based scripting techniques of the cartographic data processing aimed at the comparative analysis of the bathymetry, sediment thickness, geologic objects and geophysical settings in the study area based on various datasets. The study area is located in the Ross Sea, Antarctic. The highest values of the sediment thickness over 7,500 m are dominating in the southwest segment of the Ross Sea closer to the Victoria Land, followed by the region over the Ross Ice Shelf with values between 5,500 to 7,000 m (170°-175°W). The increased sediment thickness (2,500 to 3,000 m) was also mapped seen in the region NE off the Sulzberger Bay (70-75°S to 140-155°W), caused by the closeness of the Marie Bird Land ice coasts. A remarkable correlation between the gravity and the topography of the sea-land border in the Marie Bird Land area is well reflected in the coastal line and a set of the higher values in the free-air gravity. On the contrary, negative values (–60 to -80 mGal) are notable along the submarine toughs stretching parallel in the western part of the basin: e.g. the trough stretching in NW-SE direction in the 170°W-175°E, 65°S-68°S, between the 167°W-175°W, 70°S-72°S. Such correlations are clearly visible on the map, indicating geological lineaments and bathymetric depressions correlating with gravity grids. The paper contributes to the regional studies of the Ross Sea, the Antarctic and Polar region, and development of the cartographic technical methodologies by presenting an application of the GMT for thematic mapping., O mapeamento detalhado com base em grades de alta resolução, como GEBCO, ETOPO1, GlobSed, EGM-2008 é fundamental para vários campos das ciências da terra: geofísica, glaciologia, quaternário, sedimentologia, geologia, ciências ambientais, geomorfologia, etc. O estudo apresenta métodos de processamento de dados de mapas com script baseado em GMT visando a análise comparativa de batimetria, espessura de sedimentos, características geológicas e condições geofísicas na área de estudo com base em vários conjuntos de dados. A Área de Estudo está localizada no Mar de Ross, na Antártica. Os valores mais altos de espessura de sedimento de mais de 7.500 m prevalecem no sudoeste do Mar de Ross próximo a Victoria Land, seguido pela área acima da plataforma de gelo de Ross em valores entre 5.500 e 7.000 m (170 ° -175 ° W). O aumento da espessura do sedimento (de 2.500 a 3.000 m) também foi mapeado na área nordeste da Baía Sulzberger (de 70-75 ° S a 140-155 ° W), devido à proximidade das costas de gelo da Terra Marie Bird. A notável correlação entre a gravidade e a topografia da fronteira marítima perto da Terra Marie Bird é bem refletida na linha costeira e em muitos dos maiores valores de gravidade ao ar livre. Em contraste, os valores negativos (-60 a -80 mGal) são perceptíveis ao longo das muralhas submarinas que se estendem paralelamente na parte oeste da bacia: por exemplo, uma trincheira que se estende na direção noroeste-sudeste a 170 ° W-175 ° E, 65 ° S-68 ° S, entre 167 ° W-175 ° W, 70 ° S-72 ° S Essas correlações são claramente visíveis no mapa, indicando lineamentos geológicos e depressões batimétricas correlacionadas com grades gravimétricas. O documento contribui para estudos regionais do Mar de Ross, Antártica e região polar, bem como para o desenvolvimento de metodologias técnicas de mapeamento, introduzindo a aplicação GMT para mapeamento temático., info:eu-repo/semantics/published

The study presents geologic investigation of Yemen and the Gulf of Aden with a special focus on geophysical, seismic, tectonic and topographic mapping performed by the integrated approach of QGIS and GMT scripting. Cartographic visualization is crucial in geologic analysis, data processing and prognosis of mineral resource prospects. The region of Yemen and Gulf of Aden was formed as a result of Arabian and African plates movements and still tectonically active. Besides, the Gulf of Aden contains mineral resources of hydrocarbons which makes this region actual for investigation. The IRIS database on earthquakes was used for visualization of the magnitude of submarine earthquakes in the Gulf of Aden for the period of 2007-2020. The paper presents 6 new thematic maps for the region of Yemen and Gulf of Aden. The research presented an analysis of correlation between the geological, topographic and geophysical settings. Through combined approach of cartographic high-resolution data visualization and geologic analysis, this paper contributed to the regional geological studies of Yemen, Gulf of Aden and the Middle East., info:eu-repo/semantics/published

The paper presents spatial analysis of the geological settings and topographic structure of the Pacific Ocean by Generic Mapping Tools (GMT). The tectonic and geomorphic features of the Pacific Ocean have a complex character and include trenches, ridges, East Pacific Rise, basins, fracture zones, rifts, rises, fault systems. As a result, the seafloor fabric has a variability in sedimentation reflecting correlations between the tectonic geomorphic markers and bathymetry. The Pacific Ocean is the largest ocean on the Earth wit structural features of the seafloor playing an important role in global geomorphology. The methodology is based on the advanced cartographic toolset GMT which utilizes a shell scripting approach using a variety of modules. Data analysis was based on the comparison of high-resolution grids: 1 arc-min ETOPO1, 5-arc min GlobSed, 1-arc min gravity. The geological settings of the Pacific Ocean seafloor are referenced to the thematic layers plotted by GMT: Galapagos Rift, Eltanin and Menard Fault Systems, Gorda and Juan de Fuca ridges, fracture zones. The seabed regions characterized by the correlation in fault and fracture zones with tectonic delineations were identified. Variations of depths were compared with gravity and discussed. It was found that the rift zone of the South and East Pacific rises correlates with the topographic isolines. The tectonics showed strong correlation with the seafloor topography, and a weaker correlations with sedimentation, influenced by geomorphology, location, gravity anomalies and bathymetry. The paper contributes to the oceanographic and geologic studies of the Pacific Ocean and methodology of GMT. Specifically, five GMT scripts are presented for a reference and repeatability in similar geomatic research., info:eu-repo/semantics/published

Morphostructural features of 20 deep-sea trenches of the Pacific Ocean, the problem of their origin, info:eu-repo/semantics/published

Marine sediments can be stabilized by ultra high-strength binders: cement, Cement Kiln Dust (CKD) and slag. The properties of the stabilized soil indicate potential to their reuse. This study investigated the performance of the unconfined compressive strength (UCS) in the marine sediments stabilized by binder (cement, CKD, slag), tested by ultrasonic P-waves. Materials include 194 specimens collected from the port of Gothenborg. The experiment was performed in Swedish Geotechnical Institute (SGI). The UCS of specimens stabilized by different ratio of binders (cement, CKD, slag) was tested by resonance frequencies of the elastic P-waves. The significant increase in the UCS (>1500 kPa) was recorded for the highest values of CKD and cement, and low values of slag. The correlation profiles of low water/high binder (L W /H B ) cement/slag (40/60%) were controlled by curing time. The slag–cement–CKD simplex tests demonstrated UCS of samples with low/high water content and various binder ratio of cement (kg/m 3 ). The ratio of cement binder and curing time play a critical role in the increase of UCS followed by mechanical properties of specimens and intensity of stress. The highest values exceed 1000 m/s in P-waves. The results shown high accuracy (97%) and non-contacting approach for testing UCS of sediments. Seismic methods can be applied to test the UCS of the stabilized sediments, and also in-situ via seismic CPT, surface testing or cross hole seismic testing., info:eu-repo/semantics/published

Cartographic data visualization is crucial for geological mapping in seismically active areas of Malawi. Representation of the datasets from IRIS database is beneficial for hazard risk assessment, forecasting and damage mitigation, especially for mapping the distribution and magnitude of earthquakes. Scripting cartography using Generic Mapping Tools (GMT) was used to map seismicity in Malawi Rift Zone based on IRIS catalogue for 1972–2021. The maps show relations among the elevation heights, distribution of seismic events and volcanos in the north of the Malawi Lake. The results show correlation between elevations and seismicity with local topographic depressions. Seismic data show variability of the seismicity level with more earthquakes recorded in the north of the country. This paper contributes to the regional studies of Malawi for risk assessment and geological hazard analysis., info:eu-repo/semantics/published

This paper concerns the Caribbean Sea submarine geomorphology and bathymetry and especially the Puerto Rico Trench and the Cayman Trough, using thematic mapping, geomor- phological modelling and statistical analysis. The technical tools include Generic Mapping Tools (GMT) cartographic scripting toolset. The data include GEBCO digital bathymetric model in grid format, geopotential model of the Earth’s gravity field EGM2008, marine free-air Faye gravity anomalies from a combined GEOS3/SEASAT/GEOSAT altimeter data set, sediment thickness from the GlobSed 5-arc-minute grid model and vector layers of GMT (coastlines, river network, borders). The cross-sectioning was done by the “grdtrack” module. Differences between the form of the Puerto Rico Trench and Cayman Trough presumably result from different structure and geological evolution. The geomorphology of the segment of the Puerto Rico Trench (67.5°W and 19.90°N to 64.1°W and 19.82°N) has a gentle curvature of the slope in plane (about 13° slope steepness). The slopes are steeper in the northern part (about 32°) but higher on the continental slope. The profiles of the Puerto Rico Trench are asymmetric due to the tectonic factors. The seabed of the Cayman Trough is flat at the segment (80.0°W and 17.7°N to 78.5°W and 19.5°N). Its profile is asymmetric: northern part is steep (about 57°), southern part is about 16°. A very large negative Faye free-air gravity anomaly (up to –380 mGal) is seen in the Puerto Rico Trench, south of Cuba as well as in the north-eastern part of the Cayman Trough. The tectonic plate subduction in the Lesser Antilles, Central America and seafloor spreading is reflected in the morphostructure in the Cayman Trough and Puerto Rico Trench. Modeled cross-sectioning profiles show differences both for the Trench and Trough. In contrast with the Puerto Rico Trench with distinct density peak (680 samples for depths –5,200 to –5,400 m), the Cayman Trough has a bimodal data distribution: two peaks correspon, W artykule opisano badania wybranych elementów rzeźby dna Morza Karaibskiego na tle budowy geologicznej, tektoniki oraz wybranych właściwości pola geofizycznego wpływające- go na powstawanie rowów głębinowych. Analizę batymetrii wzdłuż Rowu Puerto Rico i Rowu Kajmańskiego wykonano z wykorzystaniem mapowania tematycznego, modelowania geomorfo- logicznego i analizy statystycznej. Wykorzystano zestaw narzędzi do tworzenia skryptów karto- graficznych w środowisku Generic Mapping Tools (GMT). Dane obejmują numeryczny model batymetryczny o strukturze GRID z bazy GEBCO, globalny model geopotencjału EGM2008, anomalie grawitacyjne z uwzględnieniem redukcji wolnopowietrznej (redukcja Faye’a) z połą- czonego zestawu danych altymetrycznych z misji GEOS3/SEASAT/GEOSAT, numeryczny model miąższości osadów o strukturze GRID i rozdzielczości 5 minut z programu GlobSed oraz warstwy wektorowe w formacie GMT (linie brzegowe, sieć rzeczna, granice). Przekrój został wykonany z wykorzystaniem modułu „grdtrack”. Wyniki pokazały różnice między strukturą Rowu Puerto Rico i Rowu Kajmańskiego, na które wpływ miała ewolucja geologiczna. Średnie nachylenie zbo- czy rowu Puerto Rico (67,5°W i 19,90°N do 64,1°W i 19,82°N) wynosi 13°. W części północnej zbocza są bardziej strome (32,09°), ale wyższe na zboczu kontynentalnym. Profile Rowu Puerto Rico są asymetryczne dla obu boków z powodu uskoków i ruchów tektonicznych płyty karaibskiej i płyty północnoamerykańskiej. Dno morskie Rowu Kajmańskiego jest płaskie w tym segmencie (80,0°W i 17,70°N do 78,5°W i 19,50°N). Jego profil jest asymetryczny: północna część jest stro- ma (57°), a południowa jest bardziej łagodna (16°). Bardzo duże ujemne anomalie grawitacyjne Faye’a na wolnym powietrzu (do –380 mGal) widoczne są w Rowie Puerto Rico, na południe od Kuby oraz w północno-wschodniej części Rowu Kajmańskiego. Subdukcja płyt tektonicznych w Małych Antylach, Ameryce Środkowej i na dnie morskim, obejmująca nieckę kajmańską, ko- reluje ze zmianami falowani, SCOPUS ar. j., info:eu-repo/semantics/published

The study is geographically focused on the Manila Trench, located in the west Pacific Ocean, South China Sea, west Philippines. The research aims at the geological mapping, analysis and visualizing variations in the submarine geomorphology of the Manila Trench. Technically, the work was done using Generic Mapping Tools scripting toolset (GMT). A combination of various GMT modules was applied for geospatial modelling. Methodology includes cartographic data integration and interpretation through approaches of data analysis: topographic plotting, geophysical modelling, geological mapping and statistical analysis. The data included SRTM, ETOPO1, geoid and gravity grids (CryoSat-2, Jason-1). Two sets of the cross-section profiles of the trench were automatically digitized. The profile transects were compared and differences in the geomorphic shape in southern and northern parts revealed. Southern part has steeper slope on the western part. Northern part is steeper on the continental slope part. The submarine terraces are located on the northern segment at depths -2,000 m. The depth and geomorphology of the slope vary for the range -3,500 to -4,500 m: minimals for the northern part with 526 samples (18.2%) for the depths -4,000 to -4,200 m. The histogram for the northern part has bimodal distribution with two peaks. The southern part shows 142 values for the minimals -3,500 to -3400 m. The statistical analyses revealed that northern part of the trench is deeper. The GMT functionality shown in this paper enabled integration and interpretation of the multi-source data: automatically digitized profiles, geological mapping, 2D and 3D bathymetric modelling, statistical analysis, mathematical approximation of the trend modelling. The GMT proved to be capable of visualizing geodata that can significantly improve Earth studies and interpretation of submarine geomorphology of the oceanic trenches through the advanced data analysis., info:eu-repo/semantics/published

The presented research aimed to perform geophysical modelling (gravity and geoid) and to evaluate the spatio-temporal variation of the marine geological data (distribution and depth of earthquakes) using combination of the Generic Mapping Tools (GMT) and available sources from the International Seismological Centre (ISC-EHB) that produce data on earthquakes as part of seismic survey and regional research projects. The target study area is a Philippine Sea basin (PSB) with two focused marginal areas: Philippine Trench and Mariana Trench, two hadal trenches located in the places of the tectonic plates subduction. Marine free-air gravity anomaly in the PSP shows higher values (>80 mGal) of the gravity fields structure at the volcanic areas and Philippine archipelago. Current study presented comparative geophysical analysis, and mapping free-air gravity and geoid in the Philippine Sea basin area. As a result of this study, the average level of earthquakes located in the Philippine Trench and Mariana Trench areas were compared, and those located in the Philippine archipelago are determined to be in the souther-western part (area of west Mindanao, south-west Visayas islands), while Luzon Islands shown shallower located earthquakes. The results on the Mariana Trench segment shown shallower located earthquakes compared of the other marginal regions of the Philippine Sea Basin. Current paper contributes to the studies on natural hazards through visualization and analysis of the earthquakes activities (occurrence and magnitude intensity), due to increasing interest to the problems of seismicity in the Pacific Ocean, which may have environmental effects causing harmful consequences and possible risks for coastal population of the Philippine islands through aftershocks and tsunami., info:eu-repo/semantics/published

The study present a case study of the Generic Mapping Tools (GMT) applied for cartographic modelling, mapping and comparative analysis of the deep-sea trenches located in southwest Pacific Ocean: the New Britain Trench (NBT) and the San Cristobal Trench (SCT). The aim was to evaluate their geomorphic variation using scripting cartographic approach of GMT. The data was processed using a sequence of the GMT modules with the main module 'grdtrack' used to visualize cross-section profiles along the trenches for their geomorphological modelling. The main grid used for topographic mapping is the SRTM DEM with 15-arc second resolution. The statistical analysis shown variability in depths of both trenches by samples in two transects. The cartographic analysis demonstrated following results. The SCT is generally deeper reaching -9,000 m, while the median for the NBT less then 7,000 m. The gradient slope of SCT is more symmetric with accurate 'V' form. In a cross-section graph, the NBT landward slope is markedly asymmetric U-shaped form and has a crescent form in the east. The NBT slope dips westwards with 35° eastward, and 41° westward, while the SCT slope has 33° oceanwards and 33,69° landwards. The difference between the geomorphology of the trenches is explained by the effects of the geotectonic evolution and actual sedimentary processes affected their formation and sculptured their structure. The marine free-air gravity anomaly illustrated density anomalies at the bathymetry in the region of NBT and SCT with range <-60.0 mGal. The geoid values are 56-66 mGal. The study contributed to the submarine geomorphic mapping and presents technical application of the cartographic functionality of GMT used for geomorphological modelling., O estudo apresenta um estudo de caso de Ferramentas de Mapeamento Genéricas (GMT) para modelagem cartográfica, mapeamento e análise comparativa das trincheiras de alto mar localizadas no sudoeste do Oceano Pacífico: a New Britain Trench (NBT) e a San Cristobal Trench (SCT). O objetivo foi avaliar sua variação geomórfica utilizando abordagem cartográfica de script de GMT. Os dados foram processados usando uma sequência de módulos GMT com o módulo principal 'grdtrack' usado para visualizar perfis de seção transversal ao longo das trincheiras para sua modelagem geomorfológica. A grade principal usada para mapeamento topográfico é o SRTM DEM com resolução de 15 segundos de arco. A análise estatística mostrou variabilidade nas profundidades de ambas as trincheiras por amostras em dois transectos. A análise cartográfica demonstrou os seguintes resultados. O SCT é geralmente mais profundo atingindo -9.000 m, enquanto a mediana para o NBT é inferior a 7.000 m. O declive do gradiente de SCT é mais simétrico com forma em 'V' precisa. Em um gráfico de seção transversal, a inclinação NBT em direção à terra é marcadamente assimétrica em forma de U e tem uma forma crescente no leste. A encosta NBT mergulha para oeste com 35 ° para leste e 41 ° para oeste, enquanto a encosta SCT tem 33 ° para o mar e 33,69 ° para terra. A diferença entre a geomorfologia das trincheiras é explicada pelos efeitos da evolução geotectônica e os processos sedimentares reais afetaram sua formação e esculpiram sua estrutura. A anomalia da gravidade marítima ao ar livre ilustrou anomalias de densidade na batimetria na região de NBT e SCT com intervalo <-60,0 mGal. Os valores do geóide são 56-66 mGal. O estudo contribuiu para o mapeamento geomórfico submarino e apresenta aplicação técnica da funcionalidade cartográfica do GMT utilizada para a modelagem geomorfológica., info:eu-repo/semantics/published

Human activity causes vibrations that propagate into the ground as high-frequency seismic waves. Measures to mitigate the coronavirus disease 2019 (COVID-19) pandemic caused widespread changes in human activity, leading to a months-long reduction in seismic noise of up to 50%. The 2020 seismic noise quiet period is the longest and most prominent global anthropogenic seismic noise reduction on record. Although the reduction is strongest at surface seismometers in populated areas, this seismic quiescence extends for many kilometers radially and hundreds of meters in depth. This quiet period provides an opportunity to detect subtle signals from subsurface seismic sources that would have been concealed in noisier times and to benchmark sources of anthropogenic noise. A strong correlation between seismic noise and independent measurements of human mobility suggests that seismology provides an absolute, real-time estimate of human activities., info:eu-repo/semantics/published

Current research focus on using Generic Mapping Tools (GMT) cartographic scripting toolset for geodata processing aimed to visualize and compare geomorphic cross-section profiles of two trenches. Study area: Yap Trench (YT) and Palau Trench (PT), two hadal trenches located in southwest Pacific Ocean. Study aim: to do automatic geomorphological modelling by digitizing profiles in a fast and precise way. This was possible using GMT based automatic data processing through modules: "grdtrack", "psxy" and "convert". The methodology consisted in extracting raster dataset from the SRTM15_PLUS, automated digitizing of the cross-sectional profiles on the selected segments, plotting profiles graphs for two trenches and statistical analysis on the bathymetry showing depth distribution. The results are the following. YT reaches-7,000 m, PT-6,200 m, that means that PT is shallower. YT has more abrupt slope and steep gradient of the profiles oceanward comparing to PT. For the diapason of-7000 m to-6000 m YT has 68 samples, while PT has 34 samples. PT has more samples below-6000 m, but YT has dominating depths at deeper values. In general, PT has more gentle geomorphic slope land and oceanwards, while YT has steeper slopes and deeper records. Topographic profiles of the axis of the YT have sharp V-shape while PT has U-shape which indicates more flat bottom of the YT with thin sediment cover of the axis. Development of the machine learning explains the importance of the geodata automatization. Automated cross-sectioning by GMT is more accurate, fast and less error-prone comparing to the manual process of digitizing by hand in traditional GIS. This paper demonstrated a GMT based methodology for the geomorphic modelling that can be applied both for submarine and terrestrial areas in similar works. The paper contributes to the development of the cartographic methodologies., info:eu-repo/semantics/published

The study area is focused on the Kuril–Kamchatka Trench, North Pacific Ocean. This region is geologically complex, notable for the lithosphere activity, tectonic plates subduction and active volcanism. The submarine geomorphology is complicated through terraces, slopes, seamounts and erosional processes. Understanding geomorphic features of such a region requires precise modelling and effective visualization of the high-resolution data sets. Therefore, current research presents a Generic Mapping Tools (GMT) based algorithm proposing a solution for effective data processing and precise mapping: iterative module-based scripting for the automated digitizing and modelling. Methodology consists of the following steps: topographic mapping of the raster grids, marine gravity and geoid; semi-automatic digitizing of the orthogonal cross-section profiles; modelling geomorphic trends of the gradient slopes; computing raster surfaces from the xyz data sets by modules nearneighbor and XYZ2grd. Several types of the cartographic projections were used: oblique Mercator, Mercator cylindrical, conic equal-area Albers, conic equidistant. The cross-section geomorphic profiles in a perpendicular direction across the two selected segments of the trench were automatically digitized. Developed algorithm of the semi-automated digitizing of the profiles enabled to visualize gradients of the slope steepness of the trench. The data were then modelled to show gradient variations in its two segments. The results of the comparative geomorphic analysis of northern and southern transects revealed variations in different parts of the trench. Presented research provided more quantitative insights into the structure and settings of the submarine landforms of the hadal trench that still remains a question for the marine geology. The research demonstrated the effectiveness of the GMT: a variety of modules, approaches and tools that can be used to produce high-quality mapping and graphics. The GMT listin, Web of Science ar.j., info:eu-repo/semantics/published

The study focuses on the statistical analysis of the impact factors affecting Mariana Trench formation. Methodology of the work is based on plotting correlation matrices by means of R programming to visualize determinants affecting geomorphic formation of the trench. The study revealed distinct unevenness of various factors affecting Mariana Trench geomorphic structure. The bathymetric determinant of the four distinct groups of the cross section profiles cause certain variability in the sedimental thickness of the basement, slope angle steepness degree, angle aspect, depth at the basement, as well as depth values (means, median and absolute minimum). Among other factors, a magmatism of the nearby area is to be mention. The closeness of the igneous volcanic areas contribute towards earthquake frequency across four tectonic plates – Mariana, Pacific, Philippine Sea and Caroline. The results demonstrated that cross-section profiles of the Mariana Trench can be divided into clusters according to their properties, such as bathymetric (depth values), geographic (latitude and longitude), geological (width of the sedimental thickness layer), magmatism (large igneous polygon areas) and tectonic (location of the tectonic plates nearby). In the scope of current research a functionality of R programming language has been tested. It proved to be as an effective tool for studying distribution of the environmental factors affecting the tectonic structure, as well as geomorphic properties at the seafloor basement of the Mariana Trench., info:eu-repo/semantics/published

Current study is focused on the GMT based modelling of the two hadal trenches located in southwest Pacific Ocean, eastwards from Australia: Tonga and Kermadec. Due to its inaccessible location, the seafloor of the deep-sea trench can only be visualized using remote sensing tools and advanced algorithms of data analysis. The importance of the developing and technical improving of the innovative methods in cartographic data processing is indisputable. Automatization in data analysis has been significantly increased over the past years. However, using programming and scripting in cartography still remains lower comparing to the use of the traditional GIS. Therefore, developing GMT-based methods for the geomorphological data processing is crucial for better understanding the landforms of the seafloor. Methodology includes application of the GMT scripting toolset for the automated digitizing of the profiles crossing the trenches in perpendicular direction. A sequence of the GMT codes enabled to visualize raster and vector data, perform geomorphological modelling, descriptive statistical data analysis and quantitative comparison of the two trenches. Using GMT, the bathymetric sample data of the Kermadec and Tonga trenches were modeled, analyzed and compared. The results show deeper bathymetry and more seafloor roughness for the Tonga. Comparing to Kermadec, Tonga Trench has steeper gradient of the profiles. The seafloor geomorphology is strongly affected by a variety of factors that shape actual form of both trenches. The experimental methodology is fully based on the GMT scripting with presented and explained codes., SCOPUS ar.j. Web of Science ar.j., info:eu-repo/semantics/published

This research is aimed to develop a migration-based earthquake location algorithm and a passive seismic imaging approach to investigate microseismicity and image steep crustal structures in the mining area Schlema-Alberoda. The dataset includes single-component records of several microseismic events which occurred between 1998 and 2012 in the area. Through some tests and comparisons, the accuracy of the localization algorithm is proved. An expected extension of pre-existing faults within the granitic body and the connection between some of the structures is comfirmed by the location results. The passive imaging procedure is conducted using only P-wave secondary arrivals from the relocated events and by applying 3-D coherency migration. The reliability of the passive imaging results is verified by comparing the final image with the results of a 3-D active reflection seismic survey in the same area. In addition, the passive image complements the 3-D active image and reveals new structures that have not been imaged previously.

This research is aimed to develop a migration-based earthquake location algorithm and a passive seismic imaging approach to investigate microseismicity and image steep crustal structures in the mining area Schlema-Alberoda. The dataset includes single-component records of several microseismic events which occurred between 1998 and 2012 in the area. Through some tests and comparisons, the accuracy of the localization algorithm is proved. An expected extension of pre-existing faults within the granitic body and the connection between some of the structures is comfirmed by the location results. The passive imaging procedure is conducted using only P-wave secondary arrivals from the relocated events and by applying 3-D coherency migration. The reliability of the passive imaging results is verified by comparing the final image with the results of a 3-D active reflection seismic survey in the same area. In addition, the passive image complements the 3-D active image and reveals new structures that have not been imaged previously.

This research is aimed to develop a migration-based earthquake location algorithm and a passive seismic imaging approach to investigate microseismicity and image steep crustal structures in the mining area Schlema-Alberoda. The dataset includes single-component records of several microseismic events which occurred between 1998 and 2012 in the area. Through some tests and comparisons, the accuracy of the localization algorithm is proved. An expected extension of pre-existing faults within the granitic body and the connection between some of the structures is comfirmed by the location results. The passive imaging procedure is conducted using only P-wave secondary arrivals from the relocated events and by applying 3-D coherency migration. The reliability of the passive imaging results is verified by comparing the final image with the results of a 3-D active reflection seismic survey in the same area. In addition, the passive image complements the 3-D active image and reveals new structures that have not been imaged previously.