Acta Geophysica最新文献

{"title":"MTIWT: moment tensor inversion using wavelet transform","authors":"Mohammad Shokri-Kaveh,&nbsp;Reza Mansouri,&nbsp;Sara Goudarzi,&nbsp;Gholam Javan-Doloei,&nbsp;Saeed Zarei","doi":"10.1007/s11600-025-01602-9","DOIUrl":"10.1007/s11600-025-01602-9","url":null,"abstract":"<div><p>In this study, we introduce a moment tensor inversion framework utilizing a wavelet transform, and we have designated our method as MTIWT. Our implementation includes a semi-automatic data preparation and a point source inversion. The method is similar to the technique in the time domain but is adjusted using wavelet coefficients. The proposed method uses the advantages of wavelet transform to estimate centroid moment tensor (CMT) solutions. The key advantage of this approach lies in its ability to assess the centroid moment tensor across a broad frequency range using a smaller number of samples as opposed to traditional time domain methods. The methodology enables users to add supplementary routines to all processing stages upon the existing framework. This allows for greater flexibility and customization of our method to meet specific needs. We show the method’s accuracy and reliability to obtain earthquake source parameters with synthetic tests and real observed seismograms.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"3811 - 3828"},"PeriodicalIF":2.1,"publicationDate":"2025-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894010","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":"Geological heterogeneity and hydrological dynamics impact on triggered earthquake genesis in Deccan basaltic terrain of western India","authors":"Kondarathi Aruna Kumari,&nbsp;Lagudu Surinaidu,&nbsp;Yedavally Srinu,&nbsp;Kalpna Gahalaut","doi":"10.1007/s11600-025-01604-7","DOIUrl":"10.1007/s11600-025-01604-7","url":null,"abstract":"<div><p>Reservoir triggered seismicity (RTS) have been documented at about 700 locations worldwide, with the Koyna-Warna region in Western India hosted the largest triggered earthquake of magnitude 6.3. Despite substantial work has been done to understand the genesis of triggered earthquakes around Koyna-Warna reservoirs, most of the research has been limited to the immediate areas of the reservoirs. In this study, we expand the investigation to encompass a broader area, aiming to explore the impact of geological heterogeneity and groundwater storage anomalies derived from GRACE satellite data on earthquake occurrence in the region. Utilising 30-m resolution digital elevation model, we extracted lineaments and generated lineament density and trend maps. Analysis reveals a total of 927 lineaments spanning 33.73 km, with shorter lineaments comprising 70% of the total count. Lineament density ranges from 0 to 1.8 km/km², indicating varying degrees of rock fracturing, with densities of 0.6–1.20 km/km² and 0.4–0.6 km/km² indicate high and moderate levels. Dominant lineament trends are observed in the N-S, NNW-SSE and WNW-ESE directions. Good correlation between lineament density, and earthquake occurrence is observed which is further validated from groundwater anomaly.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 4","pages":"3431 - 3440"},"PeriodicalIF":2.1,"publicationDate":"2025-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145144942","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":"Spatial and temporal analysis of climatic parameters in the cold arid Trans-Himalayan region of Ladakh, India","authors":"Padma Namgyal,&nbsp;Shyamal Sarkar","doi":"10.1007/s11600-025-01590-w","DOIUrl":"10.1007/s11600-025-01590-w","url":null,"abstract":"<div><p>Climate change presents significant environmental challenges, particularly in high-altitude, cold-arid regions such as Ladakh. In this study the spatial and temporal trends of temperature and precipitation in the Trans-Himalayan region of Ladakh were analyzed over a 30-year period (1991–2020). Using data from the India Meteorological Department, the Modified Mann–Kendall test and Sen’s slope estimator were applied to detect trends in climatic parameters. The results indicate no significant change in annual mean temperature; however, higher temperature was observed in February and August months. Precipitation trends reveal a significant decline of 3.68 mm in autumn precipitation from 1991 to 2020 and temperature trends reveal an 0.23 °C increase in temperature in spring season from 1991 to 2000. Overall the annual temperature and precipitation change is insignificant. Spatial analysis highlights higher temperatures and precipitation in the western part of the study area, with lower values in the east. The climatic shifts have critical implications for snow and glacier melt water in the region affecting water resources, agriculture, and local livelihoods. The findings highlight the necessity for adaptive strategies to mitigate climate impacts like water shortages and ensure environmental sustainability in this ecologically fragile Trans-Himalayan region.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4551 - 4566"},"PeriodicalIF":2.1,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893995","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":"Ground shaking hazard assessment in Jharkhand state, India, using deterministic approach","authors":"Varun Kumar","doi":"10.1007/s11600-025-01587-5","DOIUrl":"10.1007/s11600-025-01587-5","url":null,"abstract":"<div><p>Jharkhand, a mineral-rich state in India, faces specific seismic risks that necessitate thorough assessment due to its significant mining activities. This study conducts a detailed deterministic seismic hazard analysis (DSHA) to support earthquake-resilient infrastructure and hazard management. The study computes essential ground motion parameters and predicts potential earthquake scenarios by integrating geological and seismological data, including fault structures, historical seismicity, and crustal properties. Peak ground acceleration (PGA) was calculated for a return period of 2475 years, assuming a 2% probability of exceedance over 50 years. Deterministic evaluations of PGA, spectral acceleration (SA), and response spectra were performed for different periods, utilizing seismic data from various sources up to 2023. To accurately capture regional tectonic conditions, 13 ground motion prediction equations (GMPEs) were applied. The study area was divided into grids of 0.100° × 0.100° and analyzed using ArcGIS and MATLAB. A logic tree approach, incorporating weighted GMPEs, was employed to address uncertainties in the hazard assessment. The results indicate PGA values of up to 0.18 g, influenced significantly by major tectonic structures, including the Debagram Bogra fault, Singhbhum Shear Zone, Northern and Southern Purulia shear zones, Main frontal thrust (MFT), Main central thrust (MCT), and critical faults such as F233, F1329, F2423. SA values for durations ranging from 0.0 to 4.0 s were compared with Indian Standards, revealing important insights for aligning earthquake-resilient infrastructure in Jharkhand. These findings provide a robust basis for enhanced safety measures and hazard mitigation strategies in future development.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"3781 - 3798"},"PeriodicalIF":2.1,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893996","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":"Research on the inversion of passive-source Rayleigh wave dispersion curves based on the MWHO algorithm","authors":"Tao Jia,&nbsp;YinTing Wu,&nbsp;Su Tang","doi":"10.1007/s11600-025-01598-2","DOIUrl":"10.1007/s11600-025-01598-2","url":null,"abstract":"<div><p>The passive-source surface-wave method infers subsurface structures by analyzing dispersion curves extracted from ambient noise, which offers advantages in operational simplicity and greater exploration depth. However, the inversion of dispersion curves remains challenging due to the complexity of underground media and structures, constituting a complex nonlinear optimization problem. Existing approaches—including observational methods, linear local optimization, and nonlinear global optimization—each exhibit limitations. This study proposes a modified wild horse optimizer (MWHO) for passive-source Rayleigh wave dispersion curve inversion to address the constraints of current methods in deep, complex geological exploration. Four intricate geological models were tested: a five-layer velocity-increasing model, a model with hard interlayers, a six-layer velocity-increasing model, and a six-layer model containing dual high-/low-velocity layers. Results demonstrate that MWHO outperforms particle swarm optimization (PSO), genetic algorithm (GA), and differential evolution (DE) in stratigraphic identification and noise resistance, accurately reconstructing geological structures. In field applications under ground-fissure conditions, MWHO successfully inverted passive-source Rayleigh wave dispersion curves, producing 2D shear-wave velocity profiles consistent with borehole data. Future research should focus on refining MWHO, exploring its applications to other nonlinear inverse problems, and integrating advanced optimization techniques to enhance computational efficiency and accuracy.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4101 - 4112"},"PeriodicalIF":2.1,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893994","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":"Assessment of radioactivity levels and radiological hazards of soil samples from vineyards in mountainous areas in the Raparin district, Iraqi Kurdistan","authors":"Nawzad Mustafa Abdulla,&nbsp;Mohammed Ibrahim Mohammed","doi":"10.1007/s11600-025-01608-3","DOIUrl":"10.1007/s11600-025-01608-3","url":null,"abstract":"<div><p>Understanding soil radioactivity in agricultural vineyards is essential for environmental safety and public health. However, limited data exist on radioactivity levels in vineyard soils of mountainous regions, particularly those with natural irrigation sources. This study aims to assess natural and artificial radionuclide levels in vineyard soils and evaluate potential radiological hazards. A total of forty-five soil samples were collected from vineyards across five sub-districts and analyzed using an Ortec high-purity germanium (HPGe) detector (30% relative efficiency) with GammaVision software. Sampling sites were selected based on soil characteristics, irrigation sources and environmental conditions. The activity concentrations of ²²⁶Ra, ²³²Th, ⁴⁰ K and ¹³⁷Cs ranged from (5.5 ± 0.9 to 27.3 ± 0.4) Bq Kg⁻¹ with an average value of (15.5 ± 1.0) Bq Kg⁻¹, (2.9 ± 0.9 to 18.0 ± 0.6) Bq Kg⁻¹ with an average of (9.1 ± 1.0) Bq Kg⁻¹, (58.3 ± 0.1 to 318.2 ± 4.6) Bq Kg⁻¹ with an average of (174.9 ± 1.0) Bq Kg⁻¹ and (2.0 ± 0.1 to 17.3 ± 0.9) Bq Kg⁻¹, with an average value of (8.3 ± 1.0) Bq Kg⁻¹, respectively, all below global average levels. To assess potential health risks, key radiological hazard indices were computed, including radium equivalent activity (<span>({Ra}_{eq})</span>), gamma index (<span>({I}_{gamma })</span>), absorbed dose rate (<span>(D)</span>), hazard indexes (<span>({H}_{ex} and {H}_{in})</span>), annual effective dose rate (<span>({text{AEDR}}_{out} and {text{AEDR}}_{in})</span>) and excess lifetime cancer risk (<span>(ELCR)</span>). Were averaged at 41.95 ± 1.67 Bq Kg⁻¹, 0.31 ± 0.01, 19.93 ± 0.73 nGy h⁻¹, 0.11 ± 0.01 and 0.72 ± 0.01, 0.024 ± 0.01 mSv y⁻¹ and 0.189 ± 0.01 mSv y⁻¹ and 0.09 ± 0.0031 × 10^–3, respectively. The Pearson correlation analysis showed that ²²⁶Ra, ²³²Th and ⁴⁰K are strongly correlated and significantly influence radiation hazards, whereas ¹³⁷Cs exhibits weak correlations, indicating its minimal contribution to radiation risks. This study provides baseline data for vineyard soil radioactivity, contributing to environmental risk assessments in naturally irrigated agricultural areas.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4113 - 4128"},"PeriodicalIF":2.1,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893969","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":"Seismic quiescence of the seismicity associated with the Turkey earthquake occurred on 6 February 2023 using epidemic-type aftershock sequence (ETAS) model","authors":"Babita Sharma,&nbsp;Prasanta Chingtham,&nbsp; Abhishek,&nbsp;Vaishali Shukla,&nbsp;Sireesha Jaladi","doi":"10.1007/s11600-025-01603-8","DOIUrl":"10.1007/s11600-025-01603-8","url":null,"abstract":"<div><p>This study investigates the seismic activity during the Kahramanmaraş earthquake sequence that occurred on 6 February 2023 in Turkey. ETAS model has been adopted to analyse earthquake occurrence rates based on the transformed origin times and residual point process. The analysis reveals a period of approximately 5 years of reduced seismic activity preceding the earthquake sequence, indicating lower earthquake occurrence rates compared to the model’s predictions. In simpler terms, the study identifies a period of relative quiet seismic activity before the sequence, which can be attributed to the release of stress in asperity formations. Asperity formations arise from the collision of the Arabian and Eurasian plates, causing irregular stress accumulations along the Eastern Anatolian Fault Zone. Temporal distribution of <i>b</i>-values shows a statistical decline of seismicity, indicating increased stress in these existing asperities, characterized by localized mechanical coupling and material homogeneity around the areas where two major earthquakes occurred in February 2023. Particularly significant is the assessment of Coulomb stress change resulting from a magnitude, <i>M</i>_W 7.8 mainshock on the left-lateral strike Eastern Anatolian Fault Zone. This event leads to an increase in Coulomb stress change of 0.8–0.9 bar at the highly stressed Sürgü and Çardak faults. This heightened stress ultimately triggered a magnitude, <i>M</i>_W 7.5 earthquake, further contributing to the aftershock activity observed after the 2023 Kahramanmaraş earthquake sequence. In the light of these findings, this research suggests investigating periods of seismic quiescence or low <i>b</i>-values before earthquake sequences and quantifying positive stress changes afterwards. Therefore, the ultimate goal should be to reduce vulnerability, enhance resilience, and prevent the loss of life and property by these recurring disasters in the study region and in other parts of seismically active regions of the world. Hence, the risk management practices may be implemented in the seismic risk areas by the governments/policy makers and urban area planners.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"3765 - 3779"},"PeriodicalIF":2.1,"publicationDate":"2025-05-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893997","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":"Reducing equivalence effect in vertical electrical sounding interpretation using a wavelet-based convolutional neural network","authors":"Parisa Pourmajidi,&nbsp;Hojjat Haghshenas Lari","doi":"10.1007/s11600-025-01586-6","DOIUrl":"10.1007/s11600-025-01586-6","url":null,"abstract":"<div><p>Interpreting vertical electrical sounding data can be quite challenging due to its ambiguous and nonlinear nature. A significant issue in this interpretation is the equivalence phenomenon, where multiple resistivity-thickness models can correspond to the same set of recorded apparent resistivity data. This phenomenon complicates both traditional inversion methods and those utilizing neural networks. One way to mitigate these challenges is to establish an appropriate a priori model and incorporate constraints from geological information, such as borehole logs and field observations of exposed lithological sections. However, without such information, resolving these issues becomes difficult. In this study, we developed a wavelet-based convolutional neural network aimed at reducing the equivalence problem while estimating layer resistivities and thicknesses from provided apparent resistivities. This method utilizes the wavelet transform of apparent resistivity along with neural network convolutional layers, helping better identify features within the data and thereby addressing the equivalence issue more effectively. Additionally, since the method relies on a neural network, it does not require parameter estimation for each individual dataset; a single training session with suitable hyperparameters is sufficient for optimal performance. We trained and validated the model using both clear and noise-contaminated synthetic datasets and tested it with various synthetic and real datasets. The results indicate that the proposed model performs acceptably even in the presence of Gaussian random noise.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4087 - 4100"},"PeriodicalIF":2.1,"publicationDate":"2025-05-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894069","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":"Noise suppression in elastic reverse time migration based on optimized pseudo-stress decoupling algorithm","authors":"Wenhao Lv,&nbsp;Qizhen Du,&nbsp;Fuyuan Zhang,&nbsp;Xiaoyu Zhang,&nbsp;Zhen Zou,&nbsp;Li-Yun Fu","doi":"10.1007/s11600-025-01606-5","DOIUrl":"10.1007/s11600-025-01606-5","url":null,"abstract":"<div><p>Elastic reverse time migration enhances subsurface imaging for oil and gas exploration by precisely delineating subsurface structures through elastic wavefield extrapolation, but challenges remain in P and S stress wavefield separation, particularly close to the source injection point where noise of energy leakage is significant. In this paper, we introduce an optimization algorithm for pseudo-stress decoupling equations to mitigate energy leakage in elastic reverse time migration. Firstly, we optimize source loading by using an exponential decay function, reducing anomalies near the source in numerical simulations. Secondly, we refine the construction process of P and S pseudo-stress wavefield decoupling equations, maintaining the amplitude, phase, and unit information of the wavefield for more accurate stress imaging. We conduct numerical experiments using H-V model and a salt model to validate the efficacy of our methods. Numerical experiments result demonstrate that our proposed methods effectively alleviate energy leakage in the decoupled stress wavefields, significantly enhance imaging precision, achieve accurate and convergent imaging of complex subsurface structures without significant noise, and improve the robustness and reliability of stress tensor based elastic reverse time migration for subsurface geological exploration in oil and gas reservoirs.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4075 - 4086"},"PeriodicalIF":2.1,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894070","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":"Integrating energy valley optimization with machine learning for flood susceptibility mapping in Kayseri, Türkiye","authors":"Ahmet Toprak","doi":"10.1007/s11600-025-01595-5","DOIUrl":"10.1007/s11600-025-01595-5","url":null,"abstract":"<div><p>This study responds to the growing concern about flooding and its consequences, particularly in areas prone to severe meteorological events, by employing an innovative approach to identify flood susceptibility in Kayseri. The methodology combines machine learning (ML) algorithms, namely extreme gradient boosting (XGB), categorical boosting (CB), and gradient boosting (GB), with hyperparameter optimization strategies through a hybridization process utilizing the energy valley optimizer technique. A total of 6000 data points were designated for the purposes of training, testing, and validation. In order to create these models, a total of nine variables, which have been identified as influential factors in the occurrence of floods, were selected based on data availability and a review of the relevant literature. It is noteworthy that elevation and rainfall were identified as pivotal predictors across all models. The CB model demonstrated robust predictive accuracy, with a substantial majority of instances correctly classified. The AUC values for the XGB and GB models remain notably high at 0.98, indicating robust predictive power and generalization capabilities. In the test phase, the AUC values underscore the superior performance of the XGB (0.9763) and GB (0.9739) models, with the CB model also demonstrating robust results at 0.9677. This study introduces a novel approach to flood susceptibility mapping by utilizing a range of ML methods. Its key innovations lie in the superior performance of these algorithms compared to traditional methods, as well as their inherent flexibility and heuristic capabilities. The generated flood susceptibility maps offer a detailed insight into the spatial distribution of flood susceptibility, with significant implications for urban planning and disaster preparedness.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 4","pages":"3601 - 3624"},"PeriodicalIF":2.1,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11600-025-01595-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145144335","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}