Acta Geophysica最新文献

{"title":"Steady-state seepage through and below earthen dam under seismic condition: insights into hydrological mechanism","authors":"Smita Tung,&nbsp;Sibapriya Mukherjee,&nbsp;Ankit Garg,&nbsp;Radha Tomar","doi":"10.1007/s11600-024-01391-7","DOIUrl":"10.1007/s11600-024-01391-7","url":null,"abstract":"<div><p>Most of the studies in the literature focus on analyzing water flow within earthen dam under static condition. The objective of this study is to analyze water flow mechanisms within earthen dam under seismic condition. To achieve this purpose, a series of numerical simulations were conducted to model earthen embankment based on a real case scenario based on dam built in eastern province of India (i.e., South 24 Parganas in West Bengal). Further the effect of sheet pile as a seepage cutoff has been evaluated with variations in sheet pile length and location under steady-state settings for both static and seismic conditions. The study was carried out using FLAC2D version 5.0 and SEEP/W version 12.0 for a dam. The results show that pore pressure is high on the upstream side of the sheet pile during continuous seepage and quickly decreases along the sheet pile itself for all sheet pile positions. In seismic instances under steady-state conditions, when pore water pressure increases, the factor of safety decreases by 45% to 50% as compared to similar static cases. This is due to an increase in seepage force. As the sheet pile is cut off, the overall factor of safety increases as compared to the condition with no sheet pile. This study is though simplified; however, it provides insights into water flow pattern within earthen dam that need to be considered for preliminary design in regions, which are subjected to seismic loads.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"799 - 812"},"PeriodicalIF":2.3,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interactive analysis of the results of NET-VISA, a Bayesian inference system, in CTBTO’s International Data Centre bulletin production","authors":"Sherif Mohamed Ali,&nbsp;Ehsan Qorbani,&nbsp;Ronan Le Bras,&nbsp;Gérard Rambolamanana","doi":"10.1007/s11600-024-01398-0","DOIUrl":"10.1007/s11600-024-01398-0","url":null,"abstract":"<div><p>The Global Association model is a crucial tool in seismic data analysis at the International Data Centre (IDC) of the Comprehensive Nuclear-Test-Ban Treaty Organization. However, it faces challenges due to its limitations in accurately associating seismic events on a global scale. Over the past years, attempts have been undertaken to tackle these issues by introducing the Network Processing Vertically Integrated Seismic Analysis (NET-VISA) algorithm, specifically designed to enhance seismic event association across the globe. NET-VISA uses a machine learning Bayesian approach to solve the automatic association problem. NET-VISA has been implemented in operation as an additional automatic event scanner tool since January 2018. In this study, we assess the effect of the NET-VISA automatic scanner on the IDC output REB and LEB bulletins. We used three distinct time periods to evaluate the NET-VISA performance. The results show a 4.6% increase in the number of LEB events after including the NET-VISA scanner in operation, with an average of 7 additional events per day, and an increase of 17.90% in the number of scanned events. A comparison between the different bulletins in distinct periods shows NET-VISA is beneficial to build more valid events, providing opportunities to improve nuclear-test-ban monitoring. However, NET-VISA exhibits slightly reduced performance for events occurring at depths exceeding 300 km.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"71 - 81"},"PeriodicalIF":2.3,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11600-024-01398-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141505569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Application of pseudo-3D sub-bottom profile imaging technology in small submarine target detection","authors":"Tianguang Li,&nbsp;Zhiqing Huang,&nbsp;Xiaobo Zhang,&nbsp;Fansheng Meng,&nbsp;Yifan Pei,&nbsp;Jiali Guo","doi":"10.1007/s11600-024-01343-1","DOIUrl":"10.1007/s11600-024-01343-1","url":null,"abstract":"<div><p>The sub-bottom profiler is a valuable tool for obtaining high-resolution shallow stratigraphic data in marine geological and geophysical surveys. To detect and acquire the structural characteristics of small submarine objects, we developed a data processing method that utilizes 2D data to construct a 3D structural model. We conducted application experiments using sub-bottom profile detection data from Chuanshan Islands, which were explored using China’s most advanced unmanned exploration platform and commercial shallow formation profiling system. To create high-resolution 3D seafloor structure models from recorded 2D sub-bottom profile datasets, an optimized data processing sequence was devised, comprising two stages: 2D data processing and 3D data processing. The 2D data processing stage involved spectrum analysis, band-pass filtering, matching filtering, time-varying gain, and surge correction. The subsequent 3D data processing stage encompassed ping location reallocation, static correction, and extraction of feature layer information. Notably, the final pseudo-3D sub-bottom profile time slice exhibited significant amplitude variations near the target body. This methodology represents an extension of the application of 2D sub-bottom profile data, enhancing the target recognition capabilities of such data. To further improve the precision of target body characterization, we used ArcScene 10.0 to create a 3D sub-bottom profile formation model spatial database. We constructed a submarine 3D formation structure model to show the 3D structural characteristics of the target body in detail and identified a seabed target body measuring 6.4 × 9.2 × 10 m.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"393 - 405"},"PeriodicalIF":2.3,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141516855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning-based seismic characterization of deepwater turbidites in the Dangerous Grounds area, Northwest Sabah, offshore Malaysia","authors":"Ismailalwali Babikir,&nbsp;Mohamed Elsaadany","doi":"10.1007/s11600-024-01396-2","DOIUrl":"10.1007/s11600-024-01396-2","url":null,"abstract":"<div><p>Seismic interpretation is a critical aspect of hydrocarbon exploration, where geoscientists often struggle to accurately recognize patterns and anomalies in large datasets. Machine learning techniques offer a promising solution by allowing for the quick and accurate analysis of multiple and large-size seismic volumes. This study leverages seismic facies analysis, seismic attribute analysis, and supervised machine learning to identify and characterize turbidite deposits in the Dangerous Grounds region, an underexplored area recently revealed by high-resolution broadband seismic data. Through seismic stratigraphy, two distinct phases of turbidite deposition were identified: a lower unit showing higher amplitude and signs of faulting effect, and an upper, present-day unit characterized by lower amplitude and continuous reflectors. The attribute expression of these turbidites shows strong amplitude response, high relative acoustic impedance, and high gray-level co-occurrence matrix entropy emphasizing their distinctiveness from surrounding facies, with variations in reflector continuity and spectral decomposition providing further insight into their depositional processes and sediment characteristics. By applying nine machine learning classifiers with twenty seismic attributes as input, this study achieved over 99% accuracy in distinguishing turbidite facies from background, with the neural network, random forest, <i>K</i>-nearest neighbors, decision tree, and support vector machine exhibiting optimal performance. The study contributes significantly to the regional understanding of turbidite deposits through detailed machine learning-aided seismic characterization. It underscores the value of integrating domain knowledge with machine learning techniques in enhancing subsurface interpretations, offering a comprehensive methodology for seismic facies analysis in similarly complex and underexplored regions.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"379 - 391"},"PeriodicalIF":2.3,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141516856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Azimuthal crustal variations and their implications on the seismic impulse response in the Valley of Mexico","authors":"Manuel J. Aguilar-Velázquez,&nbsp;Xyoli Pérez-Campos,&nbsp;Josué Tago,&nbsp;Carlos Villafuerte","doi":"10.1007/s11600-024-01383-7","DOIUrl":"10.1007/s11600-024-01383-7","url":null,"abstract":"<div><p>Previous studies have suggested prominent variations in the seismic wave behavior at the 5 s period when traveling across the Valley of Mexico, associating them with the crustal structure and contributing to the anomalous seismic wave patterns observed each time an earthquake hits Mexico City. This article confirms the variations observed at 0.2 Hz by analyzing the Green tensor diagonal retrieved from empirical Green functions (EGF) calculated using seismic noise data cross-correlations of the vertical and horizontal components. We observe time and phase shifts between the east and north EGF components and show that they can be explained by the crustal structure from the surface up to 20 km depth; we also observe that the time and phase shifts are more significant if the distance between the source and the station increases. Additionally, the article presents an updated version of the velocity model from receiver functions and dispersion curves (VMRFDC v2.0) for the crustal structure under the Valley of Mexico. To validate this model, we compare the EGFs with synthetic Green functions determined numerically. To do so, we adaptatively meshed this model using an iterative algorithm to numerically simulate the impulse response up to 0.5 Hz. Finally, the comparisons between noise and synthetic EGF showed that the VMRFDC v2.0 model explains the time shifts and phase differences at 0.2 Hz, previously observed by independent studies, suggesting it correctly characterizes the crustal structure anomalies beneath the Valley of Mexico.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"53 - 70"},"PeriodicalIF":2.3,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11600-024-01383-7.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141516857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volcanic disaster scene classification of remote sensing image based on deep multi-instance network","authors":"Chengfan Li,&nbsp;Jingxin Han,&nbsp;Chengzhi Wu,&nbsp;Lan Liu,&nbsp;Xuefeng Liu,&nbsp;Junjuan Zhao","doi":"10.1007/s11600-024-01394-4","DOIUrl":"10.1007/s11600-024-01394-4","url":null,"abstract":"<div><p>Due to the varieties, random distributions, and rich visual characteristics of the volcanic disaster scene, traditional methods fail to fully express the complex features of volcanic disaster scenes in remote sensing images. To tackle this problem, a new multi-instance network framework with the Shift Windows Transformer (i.e., Swin-T) and attention mechanism is used to classify the volcanic disaster scene from remote sensing images (MI-STA). Firstly, via aggregating the global contextual information of remote sensing image features, the Swin-T extracts the multi-scale hierarchical features of volcano disaster scenes from remote sensing images. Secondly, the channel attention module and spatial attention module fuse to extract the features of volcanic disaster scene to enhance the description and representation for the local details and global information in volcanic disaster scenes. Last, the importance weight of different example characteristics is scored to calculate the attributive probabilities of each instance. This study elaborates an experiment on the xBD dataset and gives comparisons with the commonly used deep network models. The results show that the overall classification accuracy of the proposed method achieves 92.46% and has good performance on the test dataset. Then, we further utilize our model to classify the volcanic disaster scenes of the specific Hunga Tonga-Hunga Ha’apai on January 15, 2022, and the classification images have good consistency with the existing literature. It provides a new approach for volcanic disaster monitoring by means of remote sensing image and has broad application prospects.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"25 - 41"},"PeriodicalIF":2.3,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Completeness and calibration of the Italian Seismological Instrumental and Parametric Database (ISIDe) before 16 April 2005","authors":"Barbara Lolli,&nbsp;Gianfranco Vannucci,&nbsp;Paolo Gasperini","doi":"10.1007/s11600-024-01395-3","DOIUrl":"10.1007/s11600-024-01395-3","url":null,"abstract":"<div><p>The Italian Seismological Instrumental and Parametric Database (ISIDe) is the recipient of earthquake data collected in real-time by the Istituto Nazionale di Geofisica e Vulcanologia (INGV), and used by the studies of earthquake forecasting and seismic hazard assessment in Italy in the last decade. When it went online, following a significant improvement of the seismic acquisition system of INGV, it was including only data since the second fortnight of April 2005. About ten years later, the data since the beginning of 1985 suddenly appeared without any prior notice than the updating of the starting date of the dataset. However, the characteristics of the added data appeared clearly different from the following period both in terms of the numbers of located earthquakes and of types of magnitudes provided. After having analyzed the numerical consistency and the calibration of magnitudes of ISIDe as a function of time from 1985 to 15 April 2005, we can say that such a dataset is incomplete and poorly calibrated compared to other catalogs of Italian seismicity (CSTI, CSI, and HORUS) available for the same period. Hence, we suggest not using it as is for statistical analyses of Italian seismicity. However, it provides some magnitudes that are missed by other catalogs and thus might be used for improving such catalogs.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"43 - 51"},"PeriodicalIF":2.3,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11600-024-01395-3.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141516858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"First generation of a three-dimensional tomographic model for the uppermost mantle beneath the Zagros collision zone—constraints from full-waveform inversion","authors":"Neda Masouminia,&nbsp;Dirk-Philip van Herwaarden,&nbsp;Solvi Thrastarson,&nbsp;Habib Rahimi,&nbsp;Heiner Igel,&nbsp;Lion Krischer,&nbsp;Michael Afanasiev,&nbsp;Christian Boehm,&nbsp;Andreas Fichtner","doi":"10.1007/s11600-024-01386-4","DOIUrl":"10.1007/s11600-024-01386-4","url":null,"abstract":"<div><p>We construct a three-dimensional model of seismic velocity structure beneath the Zagros collision zone by analyzing phase measurements of seismic waveform recordings from earthquakes. We used entire waveforms from 37 earthquakes and followed a multi-scale approach for periods between 20 and 80 s. As a starting model, we used the first generation of the Collaborative Seismic Earth Model, applied the adjoint method to compute model gradients, and utilized the Broyden–Fletcher–Goldfarb–Shanno (L-BFGS) optimization algorithm to reconstruct the uppermost mantle seismic velocity structure. The Zagros collision zone consists of the margin of the Arabian platform (the Zagros Fold-and-Thrust Belt) and the margin of the Eurasian plate (the Iranian microplates). The retrieved model reveals a strong shear wave velocity contrast at a depth of approximately 180 km along the Zagros mountain belt, and topography at the surface is a piece of evidence that the deformation of the transition zone stops along the Zagros. We interpret this as an interaction between the two continental lithospheres that end at this depth. We observe that the sub-crustal lithosphere of the studied region was constructed from relatively high shear velocity structures beneath Central Iran as well as the Lut block at 80–150 km depth and continuity of high-velocity structure throughout the margin of the Arabian lithosphere from 70- to 200-km depth. It explains continental collision caused earlier thickening during the convergence of the Arabian platform toward the northeast. This observation indicates that the lithosphere of Iranian microplates has a relatively warm structure. It also shows the non-uniform distribution of a sharp velocity contrast between this structure and the strong low-velocity structure underlying it, marking the lithosphere and asthenosphere boundary (LAB). Our results locate this boundary at approximately 119-km depth. On the other hand, we observed a thickened and cold lithosphere for the margin of the Arabian lithosphere.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"11 - 24"},"PeriodicalIF":2.3,"publicationDate":"2024-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141336484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fluvial ecology disasters: the impact of the Gliwice Canal on the ecological crisis in the Oder River basin, Poland (2022)","authors":"Marek Ruman,&nbsp;Natalia Janczewska,&nbsp;Klaudia Kosek,&nbsp;Wojciech Artichowicz,&nbsp;Magdalena Nasiek,&nbsp;Magdalena Matysik","doi":"10.1007/s11600-024-01390-8","DOIUrl":"10.1007/s11600-024-01390-8","url":null,"abstract":"<div><p>In August 2022, the Oder River experienced an ecological disaster, resulting in the extinction of hundreds of aquatic organisms. Mass fish deaths also occurred during that time in the Gliwice Canal, located in southern Poland, which connects to the upper section of the Oder River. The aim of the article was to assess the impact of the waters from the Gliwice Canal on the water quality changes in the Oder River, as expressed by chloride, sulphate, nitrate, phosphate content, as well as its parameters such as conductivity, temperature, and pH. Statistical analyses were conducted based on our own research and a series of data collected by the Chief Inspectorate for Environmental Protection. Below the confluence of the Oder River with the waters of the canal, an increase in sulphates levels and a decrease in sodium content were observed. The other parameters remained unchanged. It was also noted that the magnitude of each parameter was significantly higher in the waters of the Gliwice Canal compared to the Oder River. The research conclusion is that there is no influence of the canals’ waters on the quality of the Oder River waters, both during the ecological disaster and afterwards. The presented research clearly indicates the need for separate analyses of flowing waters (with significantly higher salt and other pollutant dissolution capacity) and stagnant waters in water infrastructure (without water exchange).</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"775 - 798"},"PeriodicalIF":2.3,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11600-024-01390-8.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141345305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated geophysical exploration, water quality mapping and salinization of the coastal aquifers in Bonaberi, Douala, Cameroon","authors":"Zebaze Kevin,&nbsp;Jidong Yang,&nbsp;Anatole Eugene Djieto Lordon,&nbsp;Jianping Huang,&nbsp;Clotaire José Pako Perabi,&nbsp;Christopher Mbaringong Agyingi","doi":"10.1007/s11600-024-01389-1","DOIUrl":"10.1007/s11600-024-01389-1","url":null,"abstract":"<div><p>Water scarcity in developing counties in coastal areas is one of the difficulties that the local communities are facing despite the continuous effort made by the international communities to drive the local government to meet the sustainable development goal. To diffuse such difficulties, cost-effective geophysical techniques coupled with water quality assessment are being used as exploration tools. The study aims to identify groundwater potential zones and assess their quality for immediate use and consumption. The water quality index (WQI) map was produced for domestic and agricultural usage. The WQI was generally poor for domestic usage and needs treatment before consumption. The groundwater is adequate for agricultural use. The aquifer depth and thickness were identified and mapped. For shallow aquifers, a well can be drilled at a depth range of 35–40 m, and for deep aquifers at a depth range of 90–120 m, they were observed to have medium to high permeability. Anthropogenic activities are the main cause of the salinization observed in some of the shallow aquifers. An integrated approach enables to determination of the groundwater potential and quality within a wetland community and industrial area.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 1","pages":"755 - 773"},"PeriodicalIF":2.3,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141348855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}