Acta Geophysica最新文献

{"title":"An enhanced magnetic signature map to increase the probability of success in mineral prospectivity mapping","authors":"Gholam-Reza Elyasi,&nbsp;Abbas Bahroudi,&nbsp;Maysam Abedi","doi":"10.1007/s11600-025-01655-w","DOIUrl":"10.1007/s11600-025-01655-w","url":null,"abstract":"<div><p>An enhanced magnetic signature analyzing algorithm was proposed to deal with two following challenges of mineral prospectivity mapping (MPM) in coming decades: (1) the necessity to focus on complex exploration of conceal or covered porphyry copper deposits (PCDs) and (2) lack of innovative processing algorithms to delineate magnetic signatures of PCDs with higher predictive ability and lower degree of uncertainty. The advantages of proposed algorithm can be summarized as follows: (1) increasing the probability of success since it is found on formation model of PCDs, (2) reducing judgment and model-related uncertainties, (3) decreasing exploration search space rapidly with lower costs and (4) capability to handle the discovery of conceal PCDs. The algorithm, which includes following steps, was implemented on ground magnetic data of Sardoiyeh area in southeast of Iran: (1) identifying circular geological features (porphyry targets) using radial symmetry transformation, (2) detecting center of features with none-maximum suppression and thresholding, (3) highlighting the extent of features by employing amplitude contrast transformation and (4) determination of size and geometry of prospective targets using active contour algorithm. The results were evaluated by alteration zones resulted from remote sensing data processing, geological map, 3D Cu isoshells derived from drilled exploration boreholes and field works. All six previously known porphyry copper deposits/occurrences in the study area have been delineated successfully, and a strong correspondence has been observed between delineated targets and 3D Cu isoshells (≥ 0.2%). Approximately 15% (1.5 of 10.1 km²) of the study area has been delineated, and at least 18 new prospective targets with first priority have been proposed for further exploration. The presence of porphyry mineralization has been approved in 7 proposed targets by geological field works.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4439 - 4465"},"PeriodicalIF":2.1,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894046","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":"Absolute geomagnetic paleointensities obtained from the Americas’ presumably oldest pottery","authors":"Avto Goguitchaichvili,&nbsp;Ricardo Pacheco Baltazar,&nbsp;Rubén Cejudo,&nbsp;Rafael García-Ruiz,&nbsp;Fernando Montejo,&nbsp;Vadim Kravchinsky,&nbsp;Miguel Cervantes,&nbsp;Carlos Reina,&nbsp;Juan Morales","doi":"10.1007/s11600-025-01628-z","DOIUrl":"10.1007/s11600-025-01628-z","url":null,"abstract":"<div><p>We carried out a detailed rock-magnetic and absolute paleointensity investigation on well-dated, presumably the oldest American pottery from northern Colombia (around 4000 B.C.) The study aims to contribute to the reconstruction of Earth’s Magnetic Field strength fluctuations in the southern hemisphere, improving extremely incipient archaeomagnetic database for the Caribbean region through comprehensive rock-magnetic and archaeointensity analysis of Puerto Chacho pottery (Lat: 10° .110 N, Long: 75° .455 W). Essentially Ti-poor titanomagnetite and some fractions of hematite are main magnetic carriers of apparently pseudo-single-domain state. Individual intensities obtained from Puerto Chacho archaeological site vary from 8.7 ± 0.5 to 27.3 ± 1.2 μT, which corresponds to the Virtual Axial Dipole Moments (VADM) values between 2.2 ± 0.1 and 6.8 ± 0.3 10²² Am². The mean Puerto Chacho’s intensity determined for all twenty-three accepted values is 17.1 ± 6.2 μT, corresponding to the mean VADM of 4.2 ± 1.5 10²² Am². These values are significantly lower compared to nearby San Jacinto paleointensities (Goguitchaishvili et al. in Phys Earth Planet Interiors 31:107061, 2023), considered belonging older archaeological periods. Moreover, the absolute intensity values obtained from the Puerto Chacho pottery yielded relatively low values compared to those derived from three available global field prediction models SHA.DIF.14 K, CALS10k.1b and ArchKalmag.14 K and existing data obtained from previously published studies from Colombia and surrounding areas. A bootstrap analysis of available age distributions and updated radiocarbon calibration values indicate that absolute age intervals for Puerto Chacho are younger, which may explain the difference between the intensity values. The time interval between 6000 and 5000 BP was probably characterized by some drastic variations of the Earth’s magnetic Field strength. Although many studies have recently become available, no conclusions may be drawn about the regional fluctuations of the geomagnetic field strength.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4425 - 4438"},"PeriodicalIF":2.1,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11600-025-01628-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894039","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":"Seismotectonic implications and strong ground motion modulation of recent significant earthquakes at the North Central Red Sea, Western Saudi Arabia","authors":"Saleh Qaysi,&nbsp;Abdalla Abdelnabi,&nbsp;Hamada Saadalla","doi":"10.1007/s11600-025-01632-3","DOIUrl":"10.1007/s11600-025-01632-3","url":null,"abstract":"<div><p>The dynamic rifting of the Red Sea separated the African and Arabian plates, and poses significant earthquake hazard for the eastern and western countries particularly cities situated along the coast line either eastern Egypt or western Saudi Arabia. The northern central, and the southern parts of the Red Sea rifting have experienced various intensities and magnitudes of seismic activities that ranged from small to large earthquakes. The southern tectonic region of the Red Sea has higher earthquake activities than the central and northern ones. The current work aims to investigate the seismotectonic implications of the October 17, 2011 (<span>({M}_{L}=3.7)</span>) and the January 16, 2014 (<span>({M}_{L}=3.8)</span>) recent earthquakes that located at the Northern Central part of the Red Sea. The strong ground motion hazard parameters resulted from the two mentioned earthquakes are estimated and simulated at the Yanbu city, western Saudi Arabia by integrating the obtained source parameters in the current article with the path attenuation and the site response factors using the stochastic model. The best shearing mechanism obtained using the full waveform inversion technique indicated normal faulting with planes trending in the NNE-SW and NNW-SE directions are controlled the studied region. The integration of the source, site, and path parameters are led to strong ground motion modulation, the modulated parameters are represented by the time series, the peak ground acceleration (PGA), peak ground velocity (PGV) the peak ground displacement (PGD), and the pseud spectral acceleration (PSA). The PGA values of (0.28–0.70 cm/s²) and (0.32–84 cm/s²) are obtained for the October 17, 2011 and the January 16, 2014, respectively. The PSA values of (0.82–2.12 cm/s²) and (0.98–2.49 cm/s²) are obtained for the October 17, 2011 and the January 16, 2014, respectively. The obtained seismotectonic and hazard parameters are essential and crucial for earthquake risks and disasters resulted from the dynamical rifting of the Red Sea that affected the western Saudi Arabia urban development.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"3989 - 4002"},"PeriodicalIF":2.1,"publicationDate":"2025-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894042","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":"Magnetic exploration for geothermal power: a case study of Tattapani thermal spring","authors":"Mehboob Ur Rashid,&nbsp;Waqas Ahmed,&nbsp;Said Muhammad,&nbsp;Mohammad Arsalan Khan,&nbsp;Adham E. Ragab,&nbsp;Mohammad Mursaleen,&nbsp;Manzoore Elahi M. Soudagar","doi":"10.1007/s11600-025-01641-2","DOIUrl":"10.1007/s11600-025-01641-2","url":null,"abstract":"<div><p>Rapid industrialization and population growth have placed increasing pressure on conventional energy resources, prompting the need for reliable, low-emission alternatives. Geothermal energy, with its capacity for both thermal and electrical production, remains largely untapped in Pakistan despite abundant thermal springs and favorable tectonic settings. In this study, we evaluate the potential of the Tattapani thermal spring, located within the Hazara-Kashmir syntaxis of the Sub-Himalayan fold-thrust belt, using an integrated ground magnetic approach. A grid of 1,107 measurements spaced at 50 × 50 m was collected with a proton precession magnetometer. Hierarchical statistical analysis of total magnetic intensity and residual magnetic data delineated five distinct magnetic zones, ranging from low-intensity magnetic thermal zone to high-intensity backgrounds each corresponding to different lithologies confirmed by X-ray diffraction. The Tattapani thermal spring exhibits a total magnetic anomaly of about 500nT, which more clearly emphasizes local variations than absolute IGRF-dependent field values. First-order derivative filters (dx, dy, dz) and downward continuation to 1,000 m sharpened fault-controlled alterations, while Euler deconvolution (structural index 0–1) revealed that over 70% of causative bodies lie within 60 m of the surface, with nearly half concentrated in the MTZ. These shallow magnetic lows coincide with hydrothermal alteration halos developed along NE–SW fault intersections and an anticlinal contact between shale/marl and dolomite units. A conceptual model illustrates continuous recharge from the adjacent Poonch River through fault-bounded conduits, feeding the spring’s stable thermal output. Our findings show that Tattapani geothermal manifestation is structurally controlled by near-surface faults and is readily accessible, making it a strong candidate for sustainable power generation. To advance resource development, we recommend targeted gravity surveys to resolve deeper structures, exploratory drilling up to 01 km for direct temperature and permeability measurement, comprehensive geochemical and geotechnical testing, environmental impact assessment, within a phased exploration framework. This study shows that by integrating magnetic data with prior resistivity results can augment existing methods to refine subsurface interpretations and advance geothermal exploration in the region.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4405 - 4424"},"PeriodicalIF":2.1,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144894038","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":"Study of PP-wave azimuthal reflection coefficients in fracture-induced TTI media","authors":"Han Xiao,&nbsp;Xinmin Shang,&nbsp;Guoqiang Shen","doi":"10.1007/s11600-025-01650-1","DOIUrl":"10.1007/s11600-025-01650-1","url":null,"abstract":"<div><p>The fracture in shale is one of the most important research objectives of shale oil and gas reservoirs’ exploration and development. In seismic profiles, the resolution is considered as one-fourth of the seismic eigen wavelength. Fractures whose length are less than the resolution are usually shown as the azimuthal anisotropy of seismic travel times and amplitude. Media contain one set of tilted fractures that could be approximated as TTI media. For TTI media induced by tilted fractures, we proposed a process based on linear slip theory and anisotropic parameters, in which we could calculate azimuthal reflection coefficients by the characteristics of background media and fractures. We designed numerical tests to verify the accuracy of the process, and based on the process, we studied the influence of the polar angles and densities of fractures on the AVAZ characteristics of the induced TTI media. Compared with present methods, the proposed method could be conducted without the prior information about the anisotropy symmetry and orientation of the media and could directly calculate the azimuthal reflection coefficient of the fracture-induced media according to the characteristics of background media and fractures.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4393 - 4403"},"PeriodicalIF":2.1,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893990","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":"Delay corrected independent component analysis algorithm and its key parameters based on tunnel seismic prediction periodic interference suppression","authors":"Yonggao Yue,&nbsp;Zhiyuan Wu,&nbsp;Shang Zhang,&nbsp;Wenjie Yan,&nbsp;Huichao Shang,&nbsp;ZongLin Shi,&nbsp;Lei Wang,&nbsp;Jianpu Xi,&nbsp;Lijuan Deng,&nbsp;Gaofeng Zhou","doi":"10.1007/s11600-025-01635-0","DOIUrl":"10.1007/s11600-025-01635-0","url":null,"abstract":"<div><p>The process of tunnel seismic prediction (TSP) is often accompanied by near-periodic interference such as power frequency interference and pump vibration, which seriously affects the recognition and extraction of target signals in TSP, resulting in the failure to accurately obtain the geological structure information in front of the tunnel face. At present, the commonly used method to suppress periodic noise is notch filter, which is simple and fast, but its application range is limited. When the frequency spectrum of the periodic interference overlaps with that of the effective signal, the effective signal will be seriously damaged while the periodic interference is suppressed. To solve this problem, a delay-corrected independent component analysis (DC-ICA) algorithm is proposed, which can separate the periodic interference from the effective signal by using the statistical characteristics. The processing effect of DC-ICA algorithm is closely related to the key parameters such as the number of input seismic records, the delay time of target signal, the accuracy of frequency estimation and the frequency range. In this paper, the key parameters of DC-ICA algorithm will be deeply studied and analyzed, and then, the appropriate range of key parameters will be determined to achieve the suppression of periodic interference and high-quality extraction of target signals, so as to improve the distance and accuracy of tunnel geological advance detection.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4379 - 4391"},"PeriodicalIF":2.1,"publicationDate":"2025-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893989","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":"Characterization of the geothermal zone by remote sensing, hydrochemical, and magnetotellurics data: a case study from Lasundra, Gujarat, India","authors":"Peush Chaudhary,&nbsp;Kapil Mohan,&nbsp;Dilip Singh Kushwaha,&nbsp;Sumer Chopra,&nbsp;Ramdayal Singh,&nbsp;Prabhjot Kaur","doi":"10.1007/s11600-025-01636-z","DOIUrl":"10.1007/s11600-025-01636-z","url":null,"abstract":"<div><p>The westernmost part of India is the junction of three rift basins, namely Kachchh, Cambay, and Narmada. The Cambay rift basin, located in the Gujarat state (west of India), is well known for the presence of several geothermal zones. The Lasundra geothermal zone is located on the eastern flank of the Cambay basin, in proximity to the East Cambay Marginal fault. To characterize this geothermal zone, a combined study of remote sensing, hydrochemical, and magnetotellurics is conducted in the study area (Lasundra geothermal zone). To decipher and map the temperature anomalies associated with the geothermal zone, Advanced Spaceborne Thermal Emission and Reflection Radiometer and Landsat-8 remote sensing data are used. The hydrochemical analysis of the water sample indicates the anomalous (excess) value of salinity, fluoride, TDS, conductivity, etc. To determine the depth and extension of the geothermal zone, an MT survey is carried out near and around the geothermal zone. A total of 18 MT sites with a close interstation spacing of ~ 1–2 km are acquired along two transects. From 2-D inversion of the MT data, a ~ 100-m-thick conductive layer (&lt; 30 Ohm.m) of sediments has been seen at the surface followed by the relatively less conductive layer of Deccan trap (30–150 Ohm.m), where thickness increases towards the NW direction of the profile. The results show the presence of highly conductive zones at the depth of ~ 2.5 km and ~ 4 km, respectively, along two transects. This conductive zone may be inferred as the possible reservoir associated with the Lasundra geothermal zone. The highly resistive features (&gt; 4000 Ohm.m) may represent Granite based on the resistivity values and surrounding geology. These resistive structures are encountered at shallow depths in the SE direction and extend deeper in the NW along the transects. Apart from the presence of fractures, the possibility of some blind fault zones acting as conduits for the upward migration of thermal fluid cannot be ruled out.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4357 - 4377"},"PeriodicalIF":2.1,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s11600-025-01636-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893878","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":"Cluster and statistical analysis of spatial earthquake patterns in the South Caucasus region","authors":"Sergii Skurativskyi,&nbsp;Sergiy Mykulyak,&nbsp;Yuliya Semenova,&nbsp;Kateryna Skurativska","doi":"10.1007/s11600-025-01645-y","DOIUrl":"10.1007/s11600-025-01645-y","url":null,"abstract":"<div><p>The Caucasus region is characterized by heterogeneous and strong seismicity as a result of collision between Arabian and Eurasian tectonic plates. A rich variety of seismic events also distinguishes Azerbaijan, located in its south part. In this research, we consider the earthquakes, specifically spatial earthquake patterns that occurred in Azerbaijan and adjacent areas from 2010 to 2023. Applying density-based clustering algorithms to the earthquake catalog, the proper partitions of spatial earthquake distributions were obtained. The statistical properties of the catalog’s partition into seven clusters are studied in more detail. In particular, we consider the random variable, which is the distance from the fixed point of the earth’s surface to earthquake epicenters. The analytical approximation of the cumulative distribution function is constructed for the case when the fixed point coincides with the cluster center and epicenters in the cluster are distributed by the bivariate normal distribution. For comparison, the numerical distribution functions are evaluated on the basis of Johnson curves and good agreement is observed. Another case is also considered when the fixed point lies outside of a cluster. Under the assumption that a cluster is a circle and epicenters in it are distributed uniformly, the cumulative and probability distribution functions are derived. Applying these functions to the approximation of histograms for the distances from the Shamkir hydroelectric power station to the clusters shows that satisfactory agreement can be achieved. These results are promising for performing the seismic risk assessment for the Shamkir station or other objects of Azerbaijan’s critical infrastructure.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"3973 - 3987"},"PeriodicalIF":2.1,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893871","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":"Land subsidence site investigated by combining active and passive MASW methods: a case study from central Taiwan","authors":"Jia-Wei Liu,&nbsp;Young-Fo Chang,&nbsp;Hao Kuo-Chen","doi":"10.1007/s11600-025-01639-w","DOIUrl":"10.1007/s11600-025-01639-w","url":null,"abstract":"<div><p>Land subsidence presents significant infrastructure risks in central Taiwan due to the region’s young and weak strata. This study addresses the differential subsidence impacting a railway section by integrating of borehole data, electrical resistivity tomography (ERT) and multi-channel analysis of surface waves (MASW) methods. Limited by spread lengths, traditional ERT and active MASW are confined to shallow subsurface analysis. Our approach enhances depth investigation by combining passive MASW, which captures low-frequency data for deeper geological insights. A 131 m-long active and passive MASW surveys was conducted alongside the railway. The analysis of dispersion curves from both MASW methods showed consistent phase velocities across overlapping frequency ranges, confirming the approach’s reliability. Ambient noise analysis further validated that passive MASW could generate stable dispersion curves within 1 h under various conditions, such as day, night, and during train activities. Geophysical images revealed that the differential subsidence is primarily driven by variations in subsurface material properties. Integrating geophysical and lithological data identified a previously undetected critical soft sand layer at 11–20 m depth as a major subsidence factor. This study not only underscores the effectiveness of passive MASW but also highlights the significant benefits of combining geophysical methods. The integrated interpretation helps to characterize the identification of subsidence cause, a crucial step in improving mitigation strategy for infrastructure risks.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4339 - 4355"},"PeriodicalIF":2.1,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893867","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":"Mechanism of rock magnetic susceptibility response in coal fire zone under high-temperature environment","authors":"Shihao Yuan,&nbsp;Qiang Sun,&nbsp;Yuyang Zhao,&nbsp;Xin Hu,&nbsp;Shaofei Wang,&nbsp;Zhenlong Ge,&nbsp;Kai Chen","doi":"10.1007/s11600-025-01637-y","DOIUrl":"10.1007/s11600-025-01637-y","url":null,"abstract":"<div><p>Coal fires lead to substantial depletion of coal reserves and the emission of harmful gases, thereby causing severe ecological pollution. The magnetic method offers means to monitor alterations in the magnetic properties of coal seams and surrounding rocks after exposure to coal fires, aiding in identifying the extent of such fires. This study focuses on borehole core samples from the Hongliulin coal mine area in Yulin, Shaanxi Province, China. The samples from the six drill holes exhibited diverse lithologies and underwent high-temperature (25–800 °C) heat treatment and mass magnetic susceptibility testing in both air and nitrogen environments. The results indicate that the mass magnetic susceptibility of rocks follows a three-stage pattern during high-temperature heat treatment: minimal change up to 400 °C; at 400–600 °C, the pronounced increase in mass susceptibility is presumably attributed to the conversion of weakly magnetic minerals, such as siderite and pyrite, into strongly magnetic minerals, including magnetite, maghemite and pyrrhotite; and at 600–800 °C, the decrease in rock susceptibility observed at this stage may be due to the high-temperature oxidation of magnetite and pyrrhotite to hematite. Moreover, the mass magnetic susceptibility of the samples treated in a nitrogen environment was greater than that of the samples treated in air, which was attributed to variations in the oxygen concentration influencing the formation of magnetite and hematite. In low oxygen environments, magnetite formation prevails over hematite, leading to higher mass magnetic susceptibility. Exploring the change mechanism of the magnetization rate of different rocks after high-temperature treatment under different heating environments can provide some guidance for magnetic detection.</p></div>","PeriodicalId":6988,"journal":{"name":"Acta Geophysica","volume":"73 5","pages":"4323 - 4337"},"PeriodicalIF":2.1,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144893868","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}