pure and applied geophysics最新文献

{"title":"The Prediction Model of Seismic Variation in Complex Terrain based on the BP Neural Network with Cavities","authors":"Yanan Li,&nbsp;Hong Zhou","doi":"10.1007/s00024-024-03589-8","DOIUrl":"10.1007/s00024-024-03589-8","url":null,"abstract":"<div><p>Surface irregularities and subsurface cavities have a significant impact on seismic wave propagation, leading to either amplification or reduction of ground motion. This study focuses on creating a ground motion prediction model using artificial neural network techniques driven by a synthetically generated database. In this study, we focus on the Erlang Mountain region in Sichuan Province, China, to simulate surface ground motion using the spectral element method, considering the presence of underground cavities in the research area. The classical back propagation neural network model is used to predict changes in ground motion. The model is designed to forecast the PGA influence coefficient, and 5% damped PSV amplification ratio (for periods ranging from 0.33 to 10 s). Input parameters include the buried depth of the cavity, the distance between the surface and the cavity in the mountain projection, elevation, the first gradient of the elevation, and the second-order gradient in two orthogonal directions. The model’s performance falls within acceptable error limits. Additionally, the significance of input features is analyzed, and the model’s applicability in other regions of the ErLang Mountain is validated.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3133 - 3147"},"PeriodicalIF":1.9,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754308","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":"Hydrogeological Responses to the 2022 Tonga Volcanic Eruption in an Aseismic Region","authors":"Ella Gorbunova,&nbsp;Alina Besedina,&nbsp;Sofia Petukhova,&nbsp;Dmitry Pavlov","doi":"10.1007/s00024-024-03590-1","DOIUrl":"10.1007/s00024-024-03590-1","url":null,"abstract":"<div><p>Complex measurements being performed with a network of stations at different epicenter distances allowed to register numerous effects in various geophysical fields at the moment of peak activity of the Tonga Volcano 15/01/2022. Monitoring was also performed at the \"Mikhnevo\" Geophysical Observatory of Sadovsky Institute of Geospheres Dynamics of Russian Academy of Sciences. The aim was to detect the links between disturbances in the atmosphere, changes in ambient seismic noise, and variations in underground water level. For the first time in an aseismic region the reaction of unevenly aged aquifers to a global disturbance in the form of propagating Lamb atmospheric waves (direct and antipodal ones) as they passed around the Earth have been registered. The responses recorded in different geophysical fields were compared to background values of probability density function of power spectral density. A difference in the intensities of the responses of the confined and weakly confined aquifers to two passages of atmospheric fronts from the Tonga volcanic eruption was established. This difference corresponds to the values of barometric efficiency. Delays of the hydrogeological responses with respect to the passage of Lamb waves were observed. Synchronous measurements of hydrogeological responses to passing atmospheric disturbances produced by the Tonga volcanic eruption performed in an aseismic region add to the world database of interacting geospheres and require further consideration involving the analysis of available experimental data.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3005 - 3018"},"PeriodicalIF":1.9,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754230","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":"Co-seismic Static Stress Field and Stress Triggering of Aftershocks in the 2022 Menyuan Ms 6.9 Earthquake","authors":"Jialu Liu,&nbsp;Zhitong Jin,&nbsp;Huafeng Sun,&nbsp;Yongge Wan","doi":"10.1007/s00024-024-03584-z","DOIUrl":"10.1007/s00024-024-03584-z","url":null,"abstract":"<div><p>This study investigates the impact of the magnitude 6.9 Menyuan earthquake in Qinghai, 2022, on surrounding areas using the elastic half-space dislocation model. It calculates the co-seismic displacement and stress fields of the Menyuan earthquake and examines the mainshock's triggering effect on aftershocks based on co-seismic Coulomb stress changes. The results show: (1) The materials converge from the southwest and northeast before dispersing from the northwest and southeast around the epicenter, with subsidence in the southwest and northeast and uplift in the northwest and southeast. (2) Stress-wise, expansion occurs southwest and northeast, while compression occurs northwest and southeast of the epicenter. (3) The Coulomb stress change displays positive and negative areas. At a depth of 5 km, the aftershock triggering ratio of magnitude 3 and above is 33.33%, while at depths of 10 km and 15 km, the aftershock triggering ratio is 100%. (4) The overall pattern of distribution of Coulomb stress variations remains consistent across the different rupture models and different depths, but the distribution in the near-field close to the fault is quite significantly different. Furthermore, the differences in overall stress distribution patterns produced by changes in crustal velocity models and friction coefficients are relatively small compared to those caused by changes in rupture models, although specific numerical discrepancies can occur at certain points.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3019 - 3035"},"PeriodicalIF":1.9,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142753970","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":"Depth–Strength In-Situ Stress Model for Granite in Southeastern Tibetan Plateau and Its Implications for Stress Estimation in the Upper Crust","authors":"Junshan Xu,&nbsp;Xiwei Xu","doi":"10.1007/s00024-024-03591-0","DOIUrl":"10.1007/s00024-024-03591-0","url":null,"abstract":"<div><p>Extracting the effective information of a tectonic stress field from in-situ stress data is significantly important for engineering projects and solid Earth sciences but extremely difficult to perform because of the scattered distribution of stress data and the complexity of rock mechanical properties. A depth–strength in-situ stress model is proposed in this study by deriving the local maximum horizontal strain (<i>ε</i>_<i>H</i>) via an analysis of the depth trend of the maximum horizontal principal stress (<i>S</i>_<i>H</i>) for granite in the southeastern Tibetan Plateau (SETP). In this model, the depth trend of <i>S</i>_<i>H</i> is divided into three segments in accordance with the values of <i>S</i>_<i>H</i> and the variations in rock mechanical properties. The first segment (0–15 MPa) shows the complexity of <i>S</i>_<i>H</i> affected by multiple factors of local settings on the near-surface. The second segment (15–45 MPa) exhibits the slope of <i>S</i>_<i>H</i> against depth mainly caused by elastic variations against the decrease in porosity (or fracture closure) and increase in pressure. The third segment (&gt; 45 MPa) explains the stable depth trend of <i>S</i>_<i>H</i> in relation to the increase in pressure only. The <i>ε</i>_<i>H</i> can be extracted using the second segment, and it is in the range of 4 × 10⁻⁴–6 × 10⁻⁴ in the granite area of the SETP. The depth trend of stress in the shallow layer of the crust calculated based on the extracted <i>ε</i>_<i>H</i> is consistent with that from in-situ stress measurements. Moreover, the stress distribution along the Xianshuihe fault calculated based on the extracted <i>ε</i>_<i>H</i> suggests that the values of differential stress range within 200–250 MPa at a depth range of 10–16 km, a result that agrees well with local focal depths. The proposed model connects the in-situ stress in the shallow layers with the tectonic stress environment in the deep crust.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3103 - 3120"},"PeriodicalIF":1.9,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754288","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":"Influence of the Depth of Shallow Workings on the Probability of Sinkhole Formation and Determination of the Contribution of Mines to the Resulting Risk","authors":"Piotr Strzałkowski","doi":"10.1007/s00024-024-03583-0","DOIUrl":"10.1007/s00024-024-03583-0","url":null,"abstract":"<div><p>This paper presents a broad spectrum of factors that have an impact on the environment once underground mines have been closed, with particular emphasis on hard coal mines. Based on the review of scientific literature and own experience, several types of environmental impacts of closed mines were specified. In the author’s opinion, sinkholes pose the most serious hazard to post-mining areas. A high degree of urbanisation of the Upper Silesian Coal Basin and a wide range of mining operations conducted in the past necessitate the post-mining areas development for construction purposes. However, investing in these areas cannot carry risks and pose a threat to public safety. Therefore, a simplified method of determining the probability of sinkhole formation depending on the depth of a shallow void (excavation) in the rock mass was proposed. An algorithm has also been proposed for determining the contribution of individual mining companies to causing sinkhole hazard, which is of great importance in legal proceedings.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3121 - 3131"},"PeriodicalIF":1.9,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00024-024-03583-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142753982","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":"Seismogenic Structure and Stress State Associated with the 2023 Jishishan Earthquake, NE Tibetan Plateau","authors":"Yihai Yang,&nbsp;Qian Hua,&nbsp;Xuemei Zhang,&nbsp;Xiaofei Han,&nbsp;Chong Cao,&nbsp;Yurong Qiu","doi":"10.1007/s00024-024-03582-1","DOIUrl":"10.1007/s00024-024-03582-1","url":null,"abstract":"<div><p>On December 18, 2023, an M6.2 earthquake shock the Jishishan County (JSSEQ) in the NE Tibetan plateau. In this study, we conducted a comprehensive analysis based on focal mechanism, seismic b-value and local S-wave splitting analysis to investigate the seismogenic structure and stress state associated with the JSSEQ. The focal mechanism solution shows that the JSSEQ occurs at a centroid depth of 13 km and is associated with a node plane dipping to NNE and the other node plane dipping to WSW. The JSSEQ and its aftershocks are dominated by thrust faulting under prominently sub-horizontal WSW-ENE compression, consistent with the regional stress field. We also observe the JSSEQ occurred in the periphery of a low b-value anomaly body and a ~ 2 year decrease of b-value surrounding the mainshock before the occurrence of JSSEQ. The fast directions are sub-parallel to the maximum horizontal compressive stress with an anticlockwise rotation to the north of the Daotanghe-Linxia fault. Combined with the InSAR observation and surface geology, we deduce that the JSSEQ occurred on a highly stressed asperity of a blind NNE-dipping seismogenic fault, under the control of northeastward expansion of the Tibetan plateau. Our results provide important information for understanding the seismogenic structure and dynamic background of this earthquake that occurred in a highly concerned region.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3037 - 3049"},"PeriodicalIF":1.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00024-024-03582-1.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142753949","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":"Potential Field Imaging of Salt and Basement Structures in the Southern Zagros Foreland Basin","authors":"Vahid Teknik,&nbsp;Abdolreza Ghods,&nbsp;Sedat Inan,&nbsp;Mahnaz Rezaeian,&nbsp;Remziye Akdoğan,&nbsp;Shahab Ghomi","doi":"10.1007/s00024-024-03576-z","DOIUrl":"10.1007/s00024-024-03576-z","url":null,"abstract":"<div><p>The blind and exposed salt domes in the Fars Arc of the south-eastern Zagros Fold and Thrust Belt, are rooted in the Precambrian–Early Cambrian Hormuz Salt, which deposited over a Precambrian crystalline basement. To define the subsurface blind salt domes and examine the influences of the basement morphology on the distribution of the salt domes and their impact on hydrocarbon accumulation, we used high–resolution terrestrial magnetic and gravity data. Applying various derivative–based filters on the Bouguer gravity anomalies we identified seven blind salt domes. From those, two have characteristic topographic implications and another three have been also imaged by the earlier seismic studies. A low Bouguer anomaly with a prominence sharp variation limits the western extent of the overlying allochthonous Late Oligocene–Early Miocene Fars Salt layer. The horizontal derivative of the Bouguer anomaly highlights a distinctive lineament in the south of the Bander–e–Lengeh anticline, which is interpreted as the effect of the Fars Salt layer on folding and faulting propagation. The magnetic anomalies were not effective for detecting blind salt domes due to the presence of highly magnetised crystalline basement rock fragments within salt domes, yielding an unexpected non-zero susceptibility value similar to the surrounding sedimentary layers. This indicates the influence of crystalline basement dynamics on salt tectonism in the study area. The N–S trend of the long-wavelength magnetic anomaly of the Hendurabi Lineament extends east of the study area and reflects a basement structure. The integrated E–W gravity–magnetic forward modelling implies an N–S trending horst–graben structure in the crystalline basement, which controls the thickness of the Hormuz salt and possibly the distribution of salt domes.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3071 - 3101"},"PeriodicalIF":1.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754340","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 Motion Amplification and 3D P-Wave Velocity Model of the Crati Valley Graben (Italy)","authors":"Giuseppe Davide Chiappetta,&nbsp;Mario La Rocca","doi":"10.1007/s00024-024-03551-8","DOIUrl":"10.1007/s00024-024-03551-8","url":null,"abstract":"<div><p>The Crati valley (Calabria, Italy) is a densely populated area characterized by high seismic hazard, as inferred from the strong earthquakes that occurred in the past centuries and from the tectonic structures that border the graben. The valley extends in the NS direction between Sila massif to the east and Catena Costiera to the west. In recent years the area has been characterized by low to medium magnitude earthquakes, mostly located in the upper crust. In this work we analyzed local and regional earthquakes and seismic noise to study the seismic response and the upper crust structure in the investigated area. We analyzed 12 h of seismic noise and 24 regional earthquakes to compute the horizontal-to-vertical spectral ratio (HVSR) at all seismic stations available in the area. Results show that the two sites located on the sediments within the low-velocity anomaly are characterized by a high HVSR peak of amplitude 4 at frequency of about 0.27 Hz, which likely corresponds to the seismic resonance of the sediment-filled basin. At the same two sites, the amplification factor computed with the Standard Spectral Ratio (SSR) method applied to regional earthquakes shows values up to 6 in the frequency range 0.3–1.0 Hz. We used a selection of 332 local earthquakes in the magnitude range 0.6–4.4 to compute a high-resolution P-wave 3D velocity model of the Crati valley and surrounding terranes. The tomographic analysis shows results with a good resolution down to at least 15 km depth. A strong low-velocity anomaly at shallow depths in the well resolved sector of the valley coincides with the sediment-filled graben, the most important geological feature of the area. The results of this work provide a valuable information to be considered in the estimation of local seismic hazard.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 10","pages":"3051 - 3069"},"PeriodicalIF":1.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142754253","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":"Investigation of Kula Volcanic Field (Türkiye) Through the Inversion of Aeromagnetic Anomalies Using Success-History-Based Adaptive Differential Evolution with Exponential Population Reduction Strategy","authors":"Yunus Levent Ekinci, Çağlayan Balkaya, Hanbing Ai, Arka Roy, Şenol Özyalin","doi":"10.1007/s00024-024-03569-y","DOIUrl":"https://doi.org/10.1007/s00024-024-03569-y","url":null,"abstract":"<p>The Kula Field is the youngest volcanic center in western Türkiye, and consists of various well-preserved volcanic products. Although many geological studies have been conducted in the region, geophysical anomalies have not been studied in detail. Therefore, we analyzed the aeromagnetic anomalies of these volcanic products by performing inversion studies with a recently proposed global optimizer. This study is the first attempt to use success-history-based adaptive differential evolution algorithm (SHADE) for inverting magnetic anomalies. To reduce the computational cost, we introduced the E-SHADE scheme by incorporating an exponential population reduction strategy into the optimizer. A synthetic anomaly study revealed the mathematical nature of the handled inverse problem. Some pre- and post-inversion analyses showed the efficiency of the proposed algorithm. Additionally, we observed that the E-SHADE algorithm produced better results than a commonly used derivative-based local optimizer. Nine profile data sets including magnetic anomalies of some volcanic cones in the Kula region were inverted. It was determined that the basaltic intrusions that allow the mantle material to uplift rapidly are not very deep in the subsurface. Therefore, it is possible that the three-phased volcanism may become active again and generate new alkaline basaltic lava flows in a new phase through these shallow dykes.</p>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"30 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142267080","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":"Reliability of Moment Tensor Inversion for Different Seismic Networks","authors":"Anna Tymińska,&nbsp;Grzegorz Lizurek","doi":"10.1007/s00024-024-03570-5","DOIUrl":"10.1007/s00024-024-03570-5","url":null,"abstract":"<div><p>The article investigates the reliability of moment tensor (MT) inversion in time domain with use of first P-wave amplitude, a method used to determine the source mechanisms of earthquakes, across four different seismic networks. The study compares the synthetic tests results of MT inversion for two underground mining and two artificial reservoir monitoring seismic networks. The analysis was performed to assesses how consistency and accuracy of the results depend on different factors like: network configuration, events depth, velocity model, focal mechanism of event and applied noise. The findings highlight the impact of network configuration compared to other variables and data quality on the reliability of moment tensor inversion and provide insights into different factors which have to be considered to enhance MT accuracy. The significance of events depth in P-wave amplitude MT inversion and the necessity to consider velocity model influence, especially presence of high velocity gradient, is highlighted by the presented results.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 9","pages":"2787 - 2800"},"PeriodicalIF":1.9,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00024-024-03570-5.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142209908","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}