Contributions to Geophysics and Geodesy最新文献

{"title":"Impact of war on geophysical research in Ukraine: An eyewitness report from the formerly occupied palaeomagnetic lab","authors":"Dmytro Hlavatskyi, Ievgen Poliachenko, Galyna Melnyk, Volodymyr Bakhmutov","doi":"10.31577/congeo.2023.sp.1","DOIUrl":"https://doi.org/10.31577/congeo.2023.sp.1","url":null,"abstract":": In the 8th year of its hybrid war against Ukraine, Russia openly invaded more of Ukraine. This brutal aggression a(cid:11)ected millions of Ukrainians and divided their lives into before\" and after\". All aspects of life have su(cid:11)ered irreparable losses, in particular, in scienti(cid:12)c (cid:12)elds. This short communication is devoted to a small group of researchers who, despite all the di(cid:14)culties of the war, continue to work for the progress of fundamental science. Representing the only palaeomagnetic laboratory in Ukraine, we share with the world scienti(cid:12)c community our team’s research progress before the invasion, re(cid:13)ecting events during the occupation, and after the liberation of some regions.","PeriodicalId":43770,"journal":{"name":"Contributions to Geophysics and Geodesy","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135773170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrating seismic attributes and rock physics for delineating Pliocene reservoir in Disouq field, Nile Delta, Egypt","authors":"Ahmed HESHAM, Nadia Abdel FATTAH, Aia DAHROUG","doi":"10.31577/congeo.2023.53.1.4","DOIUrl":"https://doi.org/10.31577/congeo.2023.53.1.4","url":null,"abstract":"The Nile Delta is known as the most prolific gas province in North Africa. Gas exploration and production were the main targets over decades in the Nile Delta. The integration of petrophysical analysis, seismic interpretation, and seismic attributes could indicate the presence of gas in Disouq field, which is located in Nile Delta, Egypt. Well log data showed that the reservoir is classified into three zones (A, B, and C). These zones are characterized by low gamma ray (around 35%), with relatively high porosity (around 29%) and low water saturation (36–38%). Structural and stratigraphic interpretation was conducted in order to investigate the extension and geometry of the reservoir, in addition to the faults affecting the study area. The reservoir is represented by a channel of Pliocene age, characterized by the low impedance sand saturated by gas. Near and far offset data show the gas effect. There is an increase of the negative amplitude from near to far offset. The amplitude map and structural contours match well and show good conformance. Seismic attributes including surface attributes and “Red Green Blue/colour blending” help in delineating the extent and geometry of the reservoir, in addition to the possible prospect. Finally, the volume of original gas in place was estimated what showed that the study area is of great economic interest.","PeriodicalId":43770,"journal":{"name":"Contributions to Geophysics and Geodesy","volume":"196 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135778065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studying the high frequency seismic signals for enhanced knowledge of the shallow Earth structure and soil investigation","authors":"Mohamed A. GAMAL, George MAHER","doi":"10.31577/congeo.2023.53.1.1","DOIUrl":"https://doi.org/10.31577/congeo.2023.53.1.1","url":null,"abstract":"The Earth acts like a low-pass filter to earthquake energy so that frequencies higher than 10 Hz are rapidly attenuated. This intrigues seismologists about the seismic waves in the frequency domain 1–10 Hz, which is crucial to correctly assess the impact of seismic shaking on structures. However, not much attention has been paid to higher frequencies, probably due to its low significance and structural damage. The Earth has high frequency seismic signal (HFSS) in the audible frequency range 20–20,000 Hz and maybe higher (Gamal et al., 2020). These seismic signals result from the transformation of any energy into HFSS energy which is propagated inside the Earth, this energy may be winds, the crustal structure movement, movement due to gravitational force or any mechanical energy transformed into high frequency seismic vibrations. Fifteen different geological environments were tested in Egypt, to monitor the high frequency seismic signals (HFSS) of the subsurface soil. The present study used very high digitising frequency seismographs, not less than 8,000 to 16,000 sample per second, and a set of horizontal and vertical geophones of natural frequencies in the ranges of 4 Hz to 100 Hz. It was found that consolidated rocks have high-pitch that may reach 4,000 Hz, while weak fractured soils sound have a low-pitch, in the frequency range of 20–70 Hz. Speech and audio processing methods have been used to differentiate between these HFSS preserved inside soils and to produce the “unified HFSS map”. The “Soil HFSS map” was considered as avail science could be used in the future to give deep insight on the shallow Earth's interiors.","PeriodicalId":43770,"journal":{"name":"Contributions to Geophysics and Geodesy","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135778066","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Creation of the first UXO detection test site in Slovakia at the Rohožník military training range","authors":"Roman PAŠTEKA, Roland KARCOL, David KUŠNIRÁK, Ema NOGOVÁ, Erik ANDRÁSSY","doi":"10.31577/congeo.2023.53.1.2","DOIUrl":"https://doi.org/10.31577/congeo.2023.53.1.2","url":null,"abstract":"In the development of geophysical methods for unexploded ordnance detection, a very important role is played by UXO test sites, where known ordnance and other explosive/nonexplosive items are buried in the ground at defined positions. At such sites, various detection methods can be compared, developed and tested. Based on a cooperation between the Department of Applied Geophysics (Comenius University), Institute of Forensic Science (Slovak Ministry of Interior) and Rohožník military training range a project was performed, which was focused on the creation of the first UXO detection test site in Slovakia. It was restricted to one type of ordnance – inert tank projectiles with diameter of 100 mm. These were buried in the ground at different depths and with different orientations. Data acquisition mapping the test site was performed from the ground surface, using total field intensity magnetometers, vertical difference magnetometers and ground penetrating radar (GPR). Data acquired from all methods were processed, interpreted and archived for future reference. Most of the items were readily detected by each of the detection sensors used but the deepest items at the least favourable orientation exceeded the detection limit of the magnetometers trialled with total field performing better than the vertical gradiometers. For the application of GPR, this site was found to have favourable soil conductivity conditions permitting even the deepest items to be detected when favourably oriented. Vertical orientation presenting the smallest reflective cross-section was least favourable with some shallow items escaping detection. The most accurate depth estimations for detectable items were obtained from GPR data presented as 2D non-migrated vertical sections. Geophysical data sets acquired at seeded test sites such as the one now established at the Rohožník military training range can provide important base-line data for comparison from which development of new detection and data interpretation technologies can be evaluated.","PeriodicalId":43770,"journal":{"name":"Contributions to Geophysics and Geodesy","volume":"120 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135778064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detection of subsurface basaltic sheets and associated structures utilising forward modelling and inversion of 2D electrical resistivity data: A case study from Jebel-Qatrani, Fayoum, Egypt","authors":"Muhammad A. EL HAMEEDY, Walid M. MABROUK, Said DAHROUG, Ahmed M. METWALLY","doi":"10.31577/congeo.2023.53.1.3","DOIUrl":"https://doi.org/10.31577/congeo.2023.53.1.3","url":null,"abstract":"In the north of Fayoum Governate, Egypt, numerous extrusive flows of basalt rocks exposed on the surface and affected by weathering and erosion, forming altered basalt sheets which is the case of the Jebel-Qatrani. The study objective comes in two main folds: the first, to choose the optimum parameters required for the filed survey by generating forward models using several arrays with 3% Gaussian random noise, simulating the geology of the study area deploying a finite element modelling approach; the second, to acquire the real field data and generate the electrical resistivity tomograms to ascertain the existence, extension, and characteristics of the basaltic sheets in the subsurface. Hence, four electrical resistivity profiles with a Wenner-alpha array with 48 electrodes, 5 metre electrode spacing, and a total length of 235 metres were acquired in suitable locations based on previous aeromagnetic results in the vicinity of the study area. These profiles were inverted to derive the true resistivity distribution of the subsurface. Another objective is to detect the near-surface, Oligocene normal faulting structures associated with rifting of the Red Sea. Results from two inverted resistivity tomograms show a possible normal fault cutting through the early Oligocene Qatrani Formation at the same time as red sea rifting, confirming previous geological studies in the Fayoum region based on satellite imagery, aeromagnetic data, and geological outcrops. It is concluded that near these faults, a sheet-like body of relatively high resistivity values, representing basaltic extrusions, was detected, confirming that the basaltic presence is associated with these structural zones.","PeriodicalId":43770,"journal":{"name":"Contributions to Geophysics and Geodesy","volume":"68 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135778067","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}