pure and applied geophysics最新文献_第10页

Evaluating the Accuracy of Machine Learning, Deep Learning and Hybrid Algorithms for Flood Routing Calculations 评估洪水路由计算中机器学习、深度学习和混合算法的准确性

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-26 DOI: 10.1007/s00024-024-03575-0

Metin Sarıgöl

{"title":"Evaluating the Accuracy of Machine Learning, Deep Learning and Hybrid Algorithms for Flood Routing Calculations","authors":"Metin Sarıgöl","doi":"10.1007/s00024-024-03575-0","DOIUrl":"10.1007/s00024-024-03575-0","url":null,"abstract":"<div><p>The increase in average temperatures in the last century has caused global warming, which has increased the frequency of natural disasters. Floods are one of the most important natural disasters and harm the environment and especially human life. Flood routing techniques also play an important role in predicting floods. For this reason, the accuracy and precision of flood routing calculations are of vital importance in taking all necessary precautions before the floods reach the region and in preventing loss of life. This study aims to compare the performance of machine learning, deep learning and hybrid algorithms for flood routing prediction models in the Büyük Menderes River. In this research deep learning model Long-Short Term Memory (LSTM), machine learning model Artificial Neural Network (ANN), and hybrid machine learning models empirical mode decomposition (EMD)-ANN, and particle swarm optimization (PSO)-ANN algorithms were compared to forecast the flood routing results in two discharge observation stations in the Büyük Menderes river. The analysis results of the established ML algorithms were compared with statistical criteria such as mean error, mean absolute error, root mean square error and coefficient of determination. Additionally, Taylor diagrams, box plots, and beeswarm plot visual graphs were also used in this comparison analysis. At the end of the research, it was determined that the hybrid algorithm PSO-ANN was the most successful algorithm in forecasting flood routing results among other models according to the error values of MAE: 0.2514, MSE: 0.4613, RMSE: 0.6791, NSE: 0.941 and MBE: 0.047. Moreover, the LSTM algorithm was the approach with second estimation accuracy. The findings are vital in terms of taking necessary precautions and gaining time before floods reach any region.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 12","pages":"3485 - 3506"},"PeriodicalIF":1.9,"publicationDate":"2024-10-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889845","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}

引用次数: 0

Dynamics of the Neapolitan Volcanoes Inferred from Tiltmeter and Seismic Data Analysis: A Review 从倾斜仪和地震资料分析推断的那不勒斯火山动力学：综述

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-24 DOI: 10.1007/s00024-024-03579-w

M. Falanga, I. Aquino, P. Cusano, E. De Lauro, S. Petrosino, C. Ricco

{"title":"Dynamics of the Neapolitan Volcanoes Inferred from Tiltmeter and Seismic Data Analysis: A Review","authors":"M. Falanga, I. Aquino, P. Cusano, E. De Lauro, S. Petrosino, C. Ricco","doi":"10.1007/s00024-024-03579-w","DOIUrl":"10.1007/s00024-024-03579-w","url":null,"abstract":"<div><p>We discuss some relevant results obtained in recent works on the Neapolitan Volcanoes, i.e., Campi Flegrei, Ischia, and Vesuvius (southern Italy) regarding the coupling between ground deformation detected by tiltmeters and volcano-tectonic seismicity. Great interest is devoted to those volcanoes because of the high level of volcanic risk, to which the inhabitants are exposed. Indeed, continuous and dense monitoring of their activity is provided by the Istituto Nazionale di Geofisica Vulcanologia, which employs different types of instrumentation, among which borehole tiltmeters and seismic networks. The works we consider in the present review focus on the link between seismicity and ground tilt anomalies covering the years 2015–2022. In detail, for the Campi Flegrei caldera, a significant variation in the tiltmeter pattern has been identified. Such anomaly indicates a transition to a different dynamical regime starting since 2020, also supported by some changes in the seismicity, ground temperatures of the fumarolic field, gravimetric and geochemical parameters. Concerning Ischia Island, a variation in the main tilt direction, which switched from NNW to NNE, has been detected in response to the Md 4.0 earthquake that occurred on 21 August 2017. Finally, at Vesuvius the relation among seismicity, ground inclination, and geochemical observables was investigated over the time interval 2012–2020 providing evidence of several simultaneous anomalies as proxies of the dynamical evolution of the volcanic system. Moreover, the comparison of the static displacement induced by seismicity with the measured tilt sheds light on the strict link between these two observables. The joint analyses of the seismic and tiltmeter signals represent a powerful tool for unraveling the volcanic dynamics and separating inner sources from external contributions.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 3","pages":"1023 - 1046"},"PeriodicalIF":1.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1007/s00024-024-03579-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818179","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}

引用次数: 0

Clustering of Earthquake Sequence and Its Effect on b Value in North China 华北地震序列聚类及其对b值的影响

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-24 DOI: 10.1007/s00024-024-03588-9

Jinmeng Bi, Cheng Song, Yong Ma

{"title":"Clustering of Earthquake Sequence and Its Effect on b Value in North China","authors":"Jinmeng Bi, Cheng Song, Yong Ma","doi":"10.1007/s00024-024-03588-9","DOIUrl":"10.1007/s00024-024-03588-9","url":null,"abstract":"<div><p>Spatio-temporal clustering is a significant characteristic of earthquake sequence activity. The reasonable identification of background and cluster events is an important foundation for earthquake forecasting and seismic hazard assessment. The two data-driven declustering algorithms based on stochastic point processes and nearest-neighbor distances were used to decluster the North China. The impact of declustering on the Gutenberg-Richter <i>b</i> value is analyzed. The results indicate that the two algorithms have similar characteristics in terms of spatio-temporal declustering characteristics, sequence identification, and evolution of <i>b</i> value. Both algorithms remove the influence of significant earthquakes. The seismic activity exhibits complex spatio-temporal characteristics in North China, with certain foreshocks occurring before moderate and strong earthquakes. The trend of the declustering and non-declustering <i>b</i> values is largely consistent, which indicates that the declustering does not alter the essential change characteristics of seismic activity. The nearest neighbor algorithm tends to remove a higher proportion of small earthquakes, resulting in a decrease in the <i>b</i> value. The background <i>b</i> value of the stochastic declustering method is comparable to the entire catalog, and both are higher than the nearest neighbor method, indicating that the first event in an earthquake sequence tends to be smaller, traditionally considered a foreshock. The stochastic declustering method did not significantly modify the statistical properties of the earthquake catalog, while the declustered catalog using the nearest neighbor method showed a more pronounced Poisson characteristic. The research results can provide basic data support for sequence tracking, moderate-to-strong earthquake risk assessment, and earthquake forecasting model construction in North China.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"182 3","pages":"1163 - 1176"},"PeriodicalIF":1.9,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143818180","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}

引用次数: 0

Markov Chain Monte Carlo Solution of the Implicit Nonlinear Inverse Problem with Application to Curve Fitting and Filter Estimation 隐式非线性反问题的马尔可夫链蒙特卡罗解及其在曲线拟合和滤波器估计中的应用

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-21 DOI: 10.1007/s00024-024-03581-2

William Menke

{"title":"Markov Chain Monte Carlo Solution of the Implicit Nonlinear Inverse Problem with Application to Curve Fitting and Filter Estimation","authors":"William Menke","doi":"10.1007/s00024-024-03581-2","DOIUrl":"10.1007/s00024-024-03581-2","url":null,"abstract":"<div><p>We adapt the Metropolis–Hastings (MH) algorithm to facilitate construction of the ensemble solution of the nonlinear implicit inverse problem. The solution variable is the aggregation of the parameters of interest (model parameters) and the data. The prior probability density function (pdf) is the possibly-non-Normal joint pdf of the prior model parameters and the noisy data, and is defined in a high-dimensional space. The posterior pdf of the solution (estimated model parameter and predicted data) is the prior pdf evaluated on the lower-dimensional manifold defined by the theory. We adapt the MH algorithm to ensure that successors always satisfy the theory (that is, are on the manifold) and provide a rule for computing the probability of a given successor. Key parts of this adaption are the use of singular value decomposition to identify subspaces tangent to the manifold, and orthogonal projection, to move a preliminary estimate of a successor onto the manifold. We apply the adapted methodology to three exemplary problems: fitting a straight line to (x,y) data, when both x and y have measurement noise; fitting a circle to noisy (x,y) data, and finding a filter that takes one noisy time series into another. In these cases, the scatter of the ensemble solution about the linearized maximum likelihood solution is roughly consistent with the linearized posterior covariance, but with some non-Normal behavior. We demonstrate the usefulness of the ensemble solutions by computing empirical pdfs of several informative statistical parameters, the calculation of which would be difficult by traditional means.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 11","pages":"3299 - 3312"},"PeriodicalIF":1.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142889804","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}

引用次数: 0

Present–day and future lightning frequency as simulated by four CMIP6 models 由四个CMIP6模式模拟的现今及未来闪电频率

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-17 DOI: 10.1007/s00024-024-03587-w

Vladimir V. Guryanov, Roman P. Mikhailov, Alexey V. Eliseev

{"title":"Present–day and future lightning frequency as simulated by four CMIP6 models","authors":"Vladimir V. Guryanov, Roman P. Mikhailov, Alexey V. Eliseev","doi":"10.1007/s00024-024-03587-w","DOIUrl":"10.1007/s00024-024-03587-w","url":null,"abstract":"<div><p>The lightning flash frequency (LFF, also referred to as lightning flash rate) in four models from the Coupled Models Intercomparison Project, phase 6 is examined. For the present day (PD, 1995–2014), the models exhibit very divergent simulation of LFF in terms of multi–annual averages, interannual variability, and temperature sensitivity. The global mean multi–annual average flash frequency differs by a factor of two between the models, and only two of four models are within the reasonable distance from the LIS/OTD (Lightning Imaging Sensor/Optical Transient Detector) satellite retrievals. The model–data and inter–model differences are even more pronounced at a regional scale and during northern summer. CMIP6 simulations show a general increase in lightning flash frequency from the present day to the late 21st century, especially for the simulations with higher anthropogenic <span>(textrm{CO}_2)</span> emissions into the atmosphere. LFF sensitivity coefficient <span>(beta)</span>, which is based on differences between PD and the late 21st century are positive over most continental areas with typical values from 10 to <span>(20 {% , textrm{K}^{-1}})</span> for annual mean LFF and from 20 to <span>(60 {% , textrm{K}^{-1}})</span> for JJA averages over the northern extra–tropical continents (and even up to <span>(100 {% , textrm{K}^{-1}})</span> in some regions for individual models). At the global scale and for annual averages, this sensitivity is from 5 to <span>(17 {% , textrm{K}^{-1}})</span>. In addition, this sensitivity is markedly different from its counterpart derived from the regression of LFF on surface air temperature for PD period. The latter counterpart is negative at the global scale and changes sign between different regions (i.e, it is positive over the North America south–east and is negative over the south–western part of North America and over the India Peninsula). These regional peculiarities are reasonably simulated by the models.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 11","pages":"3351 - 3374"},"PeriodicalIF":1.9,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890418","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}

引用次数: 0

Influence of the Depth of Shallow Workings on the Probability of Sinkhole Formation and Determination of the Contribution of Mines to the Resulting Risk 浅埋作业深度对天坑形成概率的影响及矿井对天坑风险贡献的确定

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-16 DOI: 10.1007/s00024-024-03583-0

Piotr Strzałkowski

{"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}

引用次数: 0

Seismogenic Structure and Stress State Associated with the 2023 Jishishan Earthquake, NE Tibetan Plateau 2023年青藏高原东北部积石山地震发震构造与应力状态

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-15 DOI: 10.1007/s00024-024-03582-1

Yihai Yang, Qian Hua, Xuemei Zhang, Xiaofei Han, Chong Cao, Yurong Qiu

{"title":"Seismogenic Structure and Stress State Associated with the 2023 Jishishan Earthquake, NE Tibetan Plateau","authors":"Yihai Yang, Qian Hua, Xuemei Zhang, Xiaofei Han, Chong Cao, 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}

引用次数: 0

Potential Field Imaging of Salt and Basement Structures in the Southern Zagros Foreland Basin 南扎格罗斯前陆盆地盐基构造位场成像

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-08 DOI: 10.1007/s00024-024-03576-z

Vahid Teknik, Abdolreza Ghods, Sedat Inan, Mahnaz Rezaeian, Remziye Akdoğan, Shahab Ghomi

{"title":"Potential Field Imaging of Salt and Basement Structures in the Southern Zagros Foreland Basin","authors":"Vahid Teknik, Abdolreza Ghods, Sedat Inan, Mahnaz Rezaeian, Remziye Akdoğan, 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}

引用次数: 0

On the Use of Different Sources for Controlled Source Radiomagnetotellurics 可控源辐射大地电磁学中不同源的应用

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-03 DOI: 10.1007/s00024-024-03478-0

Arseny Shlykov, Stefan Schoettle, Alexander Saraev, Nikita Bobrov, Bülent Tezkan, Maria Smirnova, Pritam Yogeshwar

{"title":"On the Use of Different Sources for Controlled Source Radiomagnetotellurics","authors":"Arseny Shlykov, Stefan Schoettle, Alexander Saraev, Nikita Bobrov, Bülent Tezkan, Maria Smirnova, Pritam Yogeshwar","doi":"10.1007/s00024-024-03478-0","DOIUrl":"10.1007/s00024-024-03478-0","url":null,"abstract":"<div><p>In the controlled source radiomagnetotelluric (CSRMT) sounding method, different types of sources are in common use. However, no systematic examination of their advantages and disadvantages exists. In this paper, we analyze the electromagnetic fields of different CSRMT sources: horizontal electric dipole, HED, horizontal magnetic dipole, HMD, and vertical magnetic dipole, VMD, using both numerical modelling and field data. Positions of the boundary between the far-field and transition zones have been determined. Using 1D and 2D modelling and results of field experiments, we have shown that the HMD source has the smallest transition zone, while the VMD source has the largest one. In general, the HMD and HED sources are preferred for soundings in the far-field zone, due to the versatility of the transmitter’s geometry, and to the possibility of tensor measurements and use of 2D-3D magnetotelluric codes for data interpretation. In the case of the homogeneous half-space, for all sources the boundary between the transition and the far-field zone is farther away from a source for the impedance phase than for the apparent resistivity. Comparison of the signal magnitudes’ decay indicates that the field from the VMD source shows the slowest decrease with distance in the transition zone, while the field from the HMD source shows the fastest decrease, confirming the shorter range of measurements using the latter source. Using field experiments, we have compared the magnitudes of HED-, VMD-, and HMD-signals at odd subharmonics relative to the signal magnitude at the main frequency. We find that use of a HED source has definite advantage over loop sources for broadband frequency measurements with the square waveform from transmitter.</p></div>","PeriodicalId":21078,"journal":{"name":"pure and applied geophysics","volume":"181 11","pages":"3259 - 3277"},"PeriodicalIF":1.9,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142890121","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}

引用次数: 0

Ground Motion Amplification and 3D P-Wave Velocity Model of the Crati Valley Graben (Italy) 意大利克拉蒂谷地堑地震动放大及三维纵波速度模型

IF 1.9 4区地球科学

pure and applied geophysics Pub Date : 2024-10-02 DOI: 10.1007/s00024-024-03551-8

Giuseppe Davide Chiappetta, Mario La Rocca

{"title":"Ground Motion Amplification and 3D P-Wave Velocity Model of the Crati Valley Graben (Italy)","authors":"Giuseppe Davide Chiappetta, 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}

引用次数: 0