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11th Congress of the Balkan Geophysical Society
- Conference date: October 10-14, 2021
- Location: Online
- Published: 10 October 2021
61 - 80 of 86 results
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Tectonic Tilting Responsible for Fluviokarst Development in the Mehedinţi Plateau (Romania)
Authors H. Mitrofan, L. Niculae, L. Nutu-Dragomir and N. CruceruSummaryA particular stream catchment, part of which had been subject to karst piracy, was analysed in order to better constrain Late Pliocene tectonic events that had concerned the Mehedinţi Plateau, at the SW bend of the South Carpathians. Several geomorphic metrics (asymmetry factor, swath profiles data) have been used for this evaluation. There was consequently revealed a tectonic tilting process which had induced a gradual lateral shifting of the mainstem course over ~2 km, toward the down-tilted domain. In this way, the concerned streambed has migrated from a thick substratum of impervious rocks, toward rather extensive limestone outcrops, where the surface flow was eventually captured along underground karst conduits. This fluviokarst setting was likely generated no later than ~4 Ma. Subsequently, the considered main valley has been beheaded by incipient rivers which were developing within a newly established continental environment: the latter was installed to the detriment of the rapidly receding Dacian brackish lake, approximately at the transition from the Dacian to the Romanian times.
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Regional Coulomb Stress Variations in the North of Hellenic Subduction Zone
By H. AlkanSummaryThe East Mediterranean region is located in the Alpine-Himalayan orogenic belt and is surrounded by many active tectonic units. ln this study, the stress change is investigated by the Coulomb stress analysis for north of Hellenic Subduction zone located in East Mediterranean. The data set consists of 5 strong earthquakes (Mw≥6.0) focal mechanism solutions, occurred between 2000 and 2017 for analysis. The relationships between Coulomb stress maps and other earthquakes that occurred in the region with magnitudes less than 6.0 are analyzed to interpret stress transfer. According to the calculated Coulomb stress variation maps for the study region, the stress change demonstrates generally high or positive lobes in the north-south direction, whereas the stress change reflects low or negative lobes in the east-west direction. On the other hand, the cross-sectional view indicates that high-stress regions correlate with mainshocks and their aftershocks.
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High Resolution Habitat Mapping on the Romanian Black sea Coast: Reyna Study Area
Authors A. Popa, M. Simionescu, A. Teacă and B. IspasSummaryIn the year 2020 habitat mapping surveys has been done by researchers from NIRD GeoEcoMar (Bucharest and Constanța in Romania) in a costal area, Reyna Bay and front of the bay (noted as Reyna Area). The area belongs to Constanța city in Romania. This work included multibeam (bathymetry and backscatter), singlebeam (bathymetry) and sidescan sonar (backscatter) measurements. Direct sampling was done with Van Veen Grabs and by divers. A 1.1 sqkm area was covered by research with a total length of lines of more than 65 km. Romanian coast and shelf are particularly affected by more stress factors, both natural (erosion) and anthropogenic (pollution, fishing, coastal infrastructure) and this is a typical area in which these factors can be seen. This study presents the results of this research.
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New Insights on the Moesian Platform Tectonic Features and Geological Structures, Inferred from Regional Gravity Data
Authors I. Stanciu and I. DumitruSummaryCompilation of gravity maps from Romania and Bulgaria provided geophysical data with very good regional coverage, making possible enhanced data processing and cross-border geological interpretation of gravity data on the Moesian Platform. By merging the available gravity data into a unique dataset, a Bouguer gravity anomaly map of the Moesian Platform in Romania and Bulgaria was produced. When applying filtering techniques, the residual gravity anomaly map of the Moesian Platform provided valuable information on the Intramoesian Fault segments in both Romania and Bulgaria, as well as on the north-western continuation of the Capidava-Ovidiu and Peceneaga-Camena regional faults. Large and deep geological structures of the Moesian Platform were interpreted on gravity anomalies at crustal depths based on density contrasts as compared with the neighbouring background.
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10 Years of Rapid Earthquake Loss Estimation in Romania: Insights and Foreseen Improvements
Authors D. Toma-Danila, A. Tiganescu, C.O. Cioflan, C. Ionescu and S.F. BalanSummaryIn 2011, the Near Real-Time System for Estimating the Seismic Damage in Romania (SeisDaRo), became operational at the National Institute for Earth Physics, Romania. This system based on the SELENA software, PAGER and ShakeMap methodologies provides, within minutes after an earthquake with magnitude ≥ 3, loss estimates in terms of affected buildings and population, at city level or even smaller. Up to now, three subsequent versions have been developed and implemented - each one being scientifically and also technically improved. 10 years apart after the first version is a good moment to document the lessons learned during SeisDaRo’s exploitation, its effective contribution to seismic risk evaluation in Romania and also its potential in the management of emergency situations. As new recent international projects such as TURNkey (with the capital city - Bucharest as testbed) or REDACt (with Constanta City as testbed) are progressing, we also present how these will contribute to improved rapid earthquake loss estimations in Romania, along with a new version of SeisDaRo that will take advantage of the new developments and research initiatives at national, European and worldwide level.
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Geoelectric Studies of the Kozloduy Nuclear Power Plant Region (Programm KOZLODUY)
Authors G. Boyadzhiev, I. Logvinov, B. Srebrov and L. RakhlinSummaryIn this extended abstract is presented one geoelectric survey of the region of Nuclear Power Station (NPP) Kozloduy. Such studies are aimed at identifying conductivity anomalies associated with processes in the bowels of the Earth and, respectively, mineral deposits. Geoelectric research play a significant role in the construction of complex geophysical models of deep crustal structures, which contribute to solving the problem of predicting catastrophic natural disasters
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Climate Change: Numerical Simulations of Tropical Cyclones behavior in the Context of the Global Warming
Authors N. Zolnikova, R. Shkevov, N. Erokhin, L. Mikhailovskaya, K. Sheiretsky and H. NikolovSummaryThe climate change and especially the global warming environment in recent years bring many questions related to the numerous disasters caused by tropical cyclones (TC). The numerical study of the regional cyclogenesis dynamics based on a low parametric nonlinear model (LPNM) is continued. The model uses a system of coupled nonlinear differential equations for the maximum wind velocity and ocean surface temperature in the TC zone. Within the framework of LPNM, the generation of four powerful atmospheric vortexes with a diverse temporal dynamics during the active season in a specific area is considered. The TCs in the nonstationary background environment with lifetimes 7 - 16 days are obtained. In simulations the variability of the wind velocity and ocean’s surface temperature, as well as other effective sources of disturbances were taken into account. In the context of the global warming, the numerical calculations show TCs amplification, when the ocean surface is heated up to 0.5°C - 1°C. Therefore, maximum wind velocity in RLSTC increases sharply, the duration of the development stage also increases and the TCs move to a higher category. These facts coincide with the results received from LPNM simulations, recent registered meteorological data and environmental observations.
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Seismic Noise Model for Romania Revisited
More LessSummaryIn this paper, we analyze eleven years of continuous data (January 2010–December 2020) from 119 stations of the Romanian Seismic Network using the power spectral densities and their corresponding probability density functions (PSD PDF) in order to construct a new version of the Romanian PSD PDF mode low-noise model (RONM).
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Geomorphic Evidence of Active Faulting in the Simav Halfgraben, Western Turkey
Authors A. Caglayan, R. Saber and V. IsikSummaryTectonic geomorphology studies provide an understanding of active tectonics in a region. The Simav half-graben lies within the western part of the Anatolian Plate, characterized by normal faulting and prominent topography due to regional N-NE extensional tectonics.
We computed six geomorphic indices for 101 drainage basins along the study area. Hi values show relatively higher amounts in the southern section and are related to the neotectonic activity of the Sındırgı-Sinanpaşa Fault Zone. Sl anomalies mainly refer to the knickpoints/knickzones caused by faulting and are commonly seen in the southern section of the study area. The high values of Ksn highlight the effect of tectonic processes and indicate rapid uplift rates. According to Vf results, most of the V-shaped values are observed in the southern and northeastern parts of the Simav half-graben. Af and Bs results suggest that high tilting events and elongated basins primarily locate along the Çaysimav and Naşa Fault Zones.
The quantitative geomorphic analyses suggest that the Simav half-graben is tectonically active during the Pleistocene and Holocene epoch and probably up to the present, where the landscape has developed in tectonicdominated conditions rather than erosional processes.
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Artificial Neural Networks for Seismic Images Enhancement
Authors H. Salgado-Giles, F. Brambila-Paz, I. Caldelas and R. Montufar-ChaveznavaSummaryA processing sequence was developed based on both the Hilbert transform and the wavelet transform. The sequence’s objective is to enhance certain characteristics that may be of interest to evaluate oil occurrence through seismic data. Once processing is applied to a set of data, which belongs to one or more seismic sections, the outputs are used as training sets of an artificial neural network designed with the objective of learning to apply any processing sequence to any seismic data. This neural network is grounded in the feedforward structure, so the data flows in one direction. This neural network is built around an input layer, an output layer, and a hidden layer. The hidden layer is resultant from fifteen neurons. Not only the training but also the execution of the network considers vector arrays as inputs and outputs. This fact means that the network is executed to each trace. The neural network has demonstrated to be able to correctly apply the processing sequence. Furthermore, it performed better in terms of computational cost. In consequence less time is required to apply the network than the processing sequence.
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Evaluation of Coulomb Stress Accumulations and Magnitudefrequency (b-value) Distribution for the East Anatolian Region of Turkey
More LessSummaryThe East Anatolian Region (EAR) is struck with strong or devastating earthquakes in recent years. Therefore, an assessment of the next earthquake hazard in this part of Turkey would be useful. This type of evaluation must be focused on the identification of the seismotectonic parameters. In this paper, Coulomb stress changes in and around the East Anatolian Region of Turkey have been examined and correlated with the regional distribution of the magnitude-frequency distribution (b-value). 42 earthquakes in which occurred between 2007 and 2021 are used to calculate the Coulomb stress change, and 57,888 earthquakes that occurred between 1970 and 2021 are used to calculate the b-value distribution. Several anomaly regions of small b-value and high-stress value are found in and around the Malatya fault, Sancak Uzunpınar Fault Zone, Muş Thrust Zone, Genç fault, Göynük Fault Zone, Erciş fault, Başkale fault, and Hasan Timur fault at the beginning of 2021. An apparent correlation between the stress changes and the b-value of the earthquakes is found and this confirms the utility of the stress and bvalue maps by supporting the expected locations of the forthcoming strong/large earthquakes and mitigating earthquake hazards. Thus, special attention must be given to these anomaly areas.
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Geothermal Survey Using Live QC With Cloud MT Data
Authors E. Erdogan, I. Demirci, N.Y. Gundogdu and M.E. CandansayarSummaryFull QC of MT data is usually performed by interrupting data recordings. This limits the amount of low-frequency data recorded and therefore the quality of the degrades the response.
In this study, we present a new type of workflow supported by the live transfer of MT data over a cellular network. QC of operations and data can be performed remotely at any time under this new workflow. This permits extending the duration of the recordings and matches the expected data quality for every recording. This approach was tested during a geothermal exploration project, consisting of 3 MT systems hooked up to a cellular network. Receivers transferred the data to the cloud in real-time. Live QC allowed us to move the MT sites to the next location after acquiring the lowest desired frequency with sufficient data quality. Daily production increased by %45 using the workflow without sacrificing the data quality.
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Paleozoic oil Potential of Diyarbakir Basin in Southeast Turkey
More LessSummaryPaleozoic Oil Potantial of Diyarbakır Basin in Southeast Turkey This study aims to understand the Paleozoic oil potential of the Diyarbakır Basin of Southeastern Turkey. The Paleozoic stratigraphy of the Diyarbakır Basin consists of clastic and carbonate units deposited from the Precambrian to the end of the Permian. Early Silurian-aged Dadaş formation is the only source rock for the Paleozoic petroleum system. The oil generated in the Dadaş formation was trapped in Ordovician-aged Bedinan and Devonian-aged Hazro formations. The oil potential of the basin was estimated by mathematical basin modeling by using the software. It was determined that the Dadaş source rock generated 213.0 billion barrels of oil, of which 141.0 billion barrels were expelled, and 72.0 billion barrels remaining in the source rock.
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Near-surface Geological Context, Natural and Anthropic Features Revealed by Drone-borne Geophysics: Case Studies Near Danube Delta
Authors R.G. Dimitriu, S. Pop, I.M. Stanciu, B.M. Barbu and V. LunguSummaryOne of the main goals of geoscientists from the National Institute of Marine Geology and Geoecology – GeoEcoMar, constantly pursued in recent years is the introduction in current practice of new geophysical tools for the non-destructive, non-invasive and environment-friendly investigation of areas inaccessible, or only partially accessible to the classic geophysical mapping methodologies, such as those covered by very shallow waters, swamps and reed. The implementation of the core-project “The study of the geodynamic regime on Dobrogea, of its influence on the paleo-geographical changes produced in the Black Sea coastal area, including the Danube Delta, as well as on the presence and human activities”, funded by the Romanian Ministry of Research and Innovation made this desire achievable.
The use of aerial drones, able to carry on board miniaturized geophysical equipment, high-resolution cameras and various spectral sensors made possible, besides the study of the near-surface and deep geological structure, also the study of environmental health and the advanced investigation of archaeological sites. The paper presents, as distinct case studies, some of the results obtained by the airborne geophysical investigations carried out on board UAV systems, recently conducted in Northern Dobrogea, Romania.
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A Magnetic Investigation of the Scuttled, German Danube Flotilla and of the Risks it Poses
Authors R.G. Dimitriu, M. Tchernychev, Z. Lukic and B.M. BarbuSummaryFollowing the unsuccessful attempts to breach through upstream the river, made by the German river flotilla known as Kampfgruppe Zieb (Battle-Group Zieb), gathered in Prahovo (Serbia) section of Danube at the beginning of September 1944, the Germans decided to destroy and scuttle the entire fleet. Thus approximately 200 German war and transport ships, as well as other watercrafts, have been scuttled, the highest concentration being near Prahovo.
An unknown number of the German scuttled ships have been recovered and recommissioned by the Soviet army starting from November 1944 and several other later by Romanian authorities. On the Serbian side, six to eight watercrafts have been towed near the bank in order to clear the waterway, but they were never removed.
A high-resolution magnetic investigation carried out near Prahovo in the fall of 2020 covered a 5 km long sector of the Danube River. The survey confirmed the locations of 22 previously known shipwrecks, revealed the certain presence of another 18 shipwrecks and the possible existence of several other dozens of shallowly buried shipwrecks. The magnetic inversion made for over 2000 magnetic targets found, allowed their classification from the perspective of actually being risky UXO-type objects.
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Reuse of Existing Hydrocarbon Fields and Wells for CO2 Storage Operations in Romania
Authors A. Dudu, C. Avram, G. Iordache, C. Sava, A. Burlacu Duroiu and S. AnghelSummaryReducing the CO₂ emissions is a crucial issue for limiting global warming below 1.5°C and Carbon Capture and Storage (CCS) is the only technology that can help achieve the drastic cut on industrial CO₂ emissions needed at this point. Reusing existing hydrocarbon fields and wells for CO₂ storage operations could boost the deployment of CCS. This reuse could represent a good opportunity for implementation of CCS technology in Romania, since many of the hydrocarbon fields are approaching their end of life, following more than 160 years of hydrocarbon exploitation. The advantage of reusing fields and wells comes from the previous knowledge of the reservoir complex, the existence of proved geological traps and the relatively uniform geographical distribution. Nevertheless, the reuse of existing infrastructure comes with some associated risks for the integrity of storage which should be properly assessed and balanced when considering reuse. There are also some regulatory aspects which should be clarified for a comprehensive national legal framework enabling field and well reuse. Stakeholder awareness and acceptance is also an important factor to be taken into consideration.
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Integrating Earth Science GNSS & Satellite Thematic Service Preliminary Data and Products Results on SETTING Platform
Authors E. Nastase, A. Muntean, M. Jecu, V. Radulescu, I. Stanciu, C. Dragasanu, M. Ion and S. DimitriuSummaryThe latest years reveal to us the necessity and the interest to develop an integrated research platform to improve skills in answering fundamental scientific questions in the field of Earth sciences and questions in the socioeconomic field related to geo-hazards and geo-resources at the European level, a platform known by EPOS - European Plate Observing System. Main objectives such as the implementation of thematic services (TCS) for different communities in EPOS, the development of integrated services (ICS) for interoperability, data management and access to services, ensuring the long-term financial and legal sustainability of EPOS - ERIC and implementing services lead to the harmonization of EPOS implementations with the national strategy. As a result, many European states mirror the EPOS platform at the national level and Romania is one of them (Integrated thematic services in the field Earth Observation - A national platform for innovation – SETTING). An electronic research infrastructure was developed for data integration of products and services and offered to users. This contributed to building a community for Earth Sciences by promoting cooperation with complementary projects in geosciences (Geo, ICT, and environmental sciences) and offering services to different users and authorities.
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Discrimination Between Tectonic and Anthropic Events in Targu-Jiu Quarry Region (Romania)
Authors R. Dinescu, D. Ghica, M. Popa, I. Munteanu and M. RadulianSummaryThe Romanian Seismic Catalogue has been contaminated in the last period with events from anthropic sources, especially in the regions with active quarry activities.
In this paper, we chose as the study area the Targu-Jiu zone, located in Southern Carpathians, where the National Seismic Network (RSN) recorded both crustal events and quarry blasts.
For discrimination purposes, the events recorded in a 10-km radius circle around each quarry will be analysed through several methods, to properly identify the quarry blasts. Thus, statistical methods are used, as well as the cross-correlation technique for the recordings of Gura Zlata (GZR) seismic station.
In the first stage, a statistical analysis of the events recorded in the quarries area is performed, based on depth intervals, magnitude, working hours and days of the week. The spectrogram analyses are investigated with the DTK-GPMCC and DTK-DIVA extended CTBTO NDC-in-a-box packages developed by the CEA-DASE.
The events identified on the seismic recordings are used as templates for the cross-correlation method applied to the events recorded by the GZR for the 2010–2020 time interval.
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Sentinel-1 InSAR Time-series Monitoring of Saein Creeping Landslides in Ardebil, NW Iran
Authors R. Saber, A. Caglayan, V. Isik and F. ChiteaSummaryMapping geohazards of various scales, such as earthquakes and landslides, by Interferometric Synthetic Aperture Radar (InSAR) techniques, has been widely used in recent years. Monitoring landslide deformation with InSAR can help us better understand the mass propagation and motion evolution in space and time, respectively, and the driving factors. Saein landslide event in 2005 destroyed at least 350 m of Ardebil-Sarab roadway and power lines. The maximum horizontal and vertical displacement during the landslide were 10–20 m and 7–10 m, respectively. We selected three monitoring points in the study area to perform time-series analysis using the Sentinel-1 wide swath data acquired from 01.01.2019 to 08.04.2021 in descending orbit. In P-1 and P-3, creeping rates vary from +10.5 ± 0.5 to +22.0 ± 1.0 mm/yr and 6.1 ± 0.8 to 24.0 ± 2.0 mm/yr, respectively. Whereas the maximum creeping rates in P-2 are +7.0 ± 1.0 to −40 ± 2.0 mm/yr. The average velocity in P-1, P-2, and P-3 are 1.70, -16.5, and 3.20 mm/yr, respectively. Our results indicate that the existence of crushed zones in volcano-clastic rocks and volcanogenic sedimentary units due to the activity of the Yamchi Fault Zone has reduced stability along the slopes and accelerated creep movements.
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Assessment of August 11, 2021 Bozkurt Flood Disaster With Sentinel-2 Satellite Images, Turkey
Authors A. Caglayan, R. Saber and V. IsikSummaryFlood disasters caused by regional or local heavy rainfalls have become one of the most severe types of climaterelated natural disasters. Urban areas in Turkey frequently suffer from floods, which are common climate-related disasters. For example, heavy rainfall for three days in Kastamonu province, northern Turkey, caused a catastrophic flood event on August 11, 2021 in Bozkurt district. At least 71 people have died, many houses and shops were severely damaged, two apartments have collapsed, and the flood dragged many cars.
In this study, an automatic change detection processing for rapid flood mapping in Sentinel-2 data by analyzing the Natural Color and Normalized Difference Water Index (NDWI) images over the Bozkurt district and Ezine Valley demonstrate the effectiveness and efficiency of the remote sensing data. Natural Color images emphasized the flooding impact in Bozkurt district and transportation of mudflows through the Ezine Valley into the sea. Additionally, evaluating the NDWI data shows that approximately 1.61 km2 drought by severe flood event caused by heavy rainfall in August 2021. Bozkurt flood and similar disasters draw attention to the fact that weather is becoming more severe and more frequent due to anthropogenic global climate change.
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