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Integration of satellite and aerial images with multichannel GPR surveys in the archaeological area of Augusta Bagiennorum for an improved description of the urban setting 将奥古斯塔·巴吉恩诺勒姆考古地区的卫星和航空图像与多通道探地雷达调查相结合,以改进对城市环境的描述
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-24 DOI: 10.1016/j.jappgeo.2024.105579
A. Vergnano , P. de Vingo , G. Rosso , S. Uggè , C. Comina
The archaeological area of Augusta Bagiennorum (NW Italy) is a well-known archaeological site, extensively investigated since the end of the 19th century. Previous archaeological studies in the area allowed a preliminary definition of the urban setting through several direct soundings. However, the current knowledge of the site needs to be more complete due to the limited extension of previous archaeological surveys. To obtain a more complete description of the urban setting, we analysed aerial and satellite images and multichannel Ground Penetrating Radar (GPR) surveys, which are two remote-sensing technologies often used in this field. Aerial images showed vegetation cropmark patterns in different areas, depending on the time of the day, year, and camera acquisition setup. The GPR surveys locally confirmed the presence of buried structures in correspondence with the cropmarks, and provided a more detailed view of the underground features. The GPR was also helpful in adding Ground Control Points for georeferencing hot-air balloon images. The combined view of aerial and GPR images allowed us to confirm the overall extent of the archaeological area, as reported in past archaeological reports. However, some of the observed structures were located outside the previously known extent of the town. The orientation of some suggests that the streets of Augusta Bagiennorum are not always arranged in a perpendicular pattern, typical of the Roman orthogonal town planning. The adopted methodological approach could be a valuable tool in similar case studies, since it provides multiscale information composed of both overall views and detailed images.
奥古斯塔Bagiennorum考古区(意大利西北部)是一个著名的考古遗址,自19世纪末以来进行了广泛的调查。以前在该地区进行的考古研究通过几次直接探测对城市环境进行了初步定义。然而,由于以往考古调查的延伸有限,目前对该遗址的了解还需要更加完整。为了获得更完整的城市环境描述,我们分析了航空和卫星图像以及多通道探地雷达(GPR)调查,这是该领域常用的两种遥感技术。航拍图像显示了不同地区的植被裁切标记模式,这取决于一天中的时间、一年中的时间和相机采集设置。探地雷达在当地的调查证实了与坡度标记相对应的埋藏结构的存在,并提供了更详细的地下特征视图。探地雷达还有助于增加地面控制点,以便对热气球图像进行地理参考。航空和探地雷达图像的结合视图使我们能够确认考古区域的总体范围,正如过去的考古报告所报告的那样。然而,一些观察到的建筑位于以前已知的城镇范围之外。一些方向表明,奥古斯塔·巴吉恩诺勒姆的街道并不总是以垂直的模式排列,这是典型的罗马正交城镇规划。所采用的方法方法在类似的案例研究中可能是一个有价值的工具,因为它提供了由总体视图和详细图像组成的多尺度信息。
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引用次数: 0
Seismic Site Characterization of Coimbatore city, Tamil Nadu, India using the Multi-channel Analysis of Surface Waves (MASW) test and Correlations between shear-wave velocity and SPT - N 利用多通道面波分析 (MASW) 试验和剪切波速度与 SPT 之间的相关性分析印度泰米尔纳德邦哥印拜陀地震遗址特征 - N
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-20 DOI: 10.1016/j.jappgeo.2024.105575
Manoharan Sambath , Sembulichampalayam Sennimalai Chandrasekaran , Sandeep Maithani , Ganapathy Pattukandan Ganapathy
Seismic Site Characterization involves the qualitative assessment of top-soil properties that have the capability of amplifying the generated earthquake ground motions. The geotechnical properties of topsoil refer to the top 30-m subsurface profile which plays a vital role in seismic microzonation and Ground Response Analysis (GRA) studies. Among various geotechnical parameters, shear-wave velocity (Vs) of the top 30 m subsurface is mainly linked to seismic site characterization and amplification studies. The average shear-wave velocity of the top 30 m subsurface, Vs(30), has been used for seismic site classification in accordance with the National Earthquake Hazard Reduction Program (NEHRP) and various building codes. In this study, an attempt has been made to retrieve the geospatial variation of average shear-wave velocity for Coimbatore city using the active Multi-channel Analysis of Surface Waves (MASW) test which is one of the non-destructive geophysical tests. To retrieve the spatial distribution of shear-wave velocity (Vs), the test was carried out at 35 locations in the vicinity of important structures, schools, colleges, and hospitals within the city. The seismic records have been acquired in the field and analyzed using the winMASW software. From the one-dimensional MASW test, the study area has an average Vs(30) in the range of 640 m/s to 909 m/s and has been classified as site-class “BC” (soft rock) according to NEHRP standards. These test results have been validated using the collected SPT bore log data from various locations, including 40 sites in the vicinity of the conducted MASW tests. The site-specific correlation between the shear-wave velocity (Vs) and the corrected SPT N- Value, N1(60), and between Vs and shear modulus (G) have been developed for Coimbatore city with a regression coefficient of 0.79 and 0.83 respectively. From the fundamental site period map, the study area has a site period in the range of 0.1 to 0.2 s, which indicates that 1- to 2- storey buildings that are densely distributed throughout the city may lead to damage in case of probable future earthquakes. This study bridges the connectivity from the evaluated bedrock acceleration using the Seismic Hazard Analysis (SHA) and provides insights for evaluating surface acceleration using GRA studies.
地震场地特征描述包括对表土特性的定性评估,这些特性具有放大地震产生的地面运动的能力。表层土的岩土特性指的是表层 30 米以下的剖面,在地震微区划分和地震动响应分析(GRA)研究中起着至关重要的作用。在各种岩土参数中,表层 30 米以下的剪切波速度(Vs)主要与地震场地特征和放大研究有关。根据国家地震危险性降低计划(NEHRP)和各种建筑规范,表层下 30 米顶部的平均剪切波速度 Vs(30) 已被用于地震遗址分类。在本研究中,我们尝试使用主动多通道地表波分析(MASW)测试来检索哥印拜陀城市平均剪切波速度的地理空间变化,该测试是非破坏性地球物理测试之一。为了检索剪切波速度(Vs)的空间分布,测试在市内重要建筑、学校、学院和医院附近的 35 个地点进行。地震记录在现场采集,并使用 winMASW 软件进行分析。根据一维 MASW 试验,研究区域的平均 Vs(30) 在 640 米/秒至 909 米/秒之间,根据 NEHRP 标准被划分为 "BC "类场地(软岩)。这些测试结果已利用从不同地点收集的 SPT 钻孔记录数据进行了验证,其中包括进行 MASW 测试的附近 40 个地点。哥印拜陀的剪切波速度(Vs)与校正 SPT N 值(N1(60))之间,以及 Vs 与剪切模量(G)之间的回归系数分别为 0.79 和 0.83。从基本场地周期图来看,研究区域的场地周期在 0.1 至 0.2 秒之间,这表明在未来可能发生的地震中,密集分布在城市各处的 1 至 2 层建筑可能会导致损坏。本研究利用地震危险性分析 (SHA) 评估了基岩加速度,为利用 GRA 研究评估地表加速度提供了启示。
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引用次数: 0
Validation of four resistivity mixing models on field time lapse geoelectrical measurements from fine-grained soil undergoing freeze-thaw cycles 在对经历冻融循环的细粒土壤进行的实地延时地质电学测量中验证四种电阻率混合模型
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-19 DOI: 10.1016/j.jappgeo.2024.105572
Soňa Tomaškovičová, Thomas Ingeman-Nielsen
<div><div>Resistivity mixing models relate porosity, phase composition and specific resistivities of ground materials to their bulk (effective) electrical properties. These models were typically derived for calculating hydrocarbon saturation from geophysical logs. In permafrost monitoring applications, they have been used to link ground electrical response to its phase composition, with focus on unfrozen water vs. ice content, and to derive changes in ground ice content from repeated resistivity acquisitions. Such quantitative interpretations rely on validity of the mixing models in a context different from the one they were derived in. To increase the reliability of the permafrost forecasts that are based on repeated resistivity surveys, we undertook validation of four selected resistivity mixing model formulations: i) the original Archie's law, ii) the Archie's law with an ice-content dependent cementation exponent <span><math><mi>m</mi></math></span> (Archie-M), iii) a modification of the Archie's law for multiple conducting phases (Archie-N), and iv) the geometric mean model (GM). The model application context was permafrost monitoring and fate forecasting on natural fine-grained soil undergoing cycles of freezing and thawing, based on indirect (geophysical), in-situ time-lapse resistivity measurements. The purpose of the calibrated resistivity models was to derive the phase composition of the ground from in-situ resistivity measurements, with acceptable quantitative reliability, notably with respect to the amount and changes of ice and water content. In our validation framework, daily temperature-dependent soil phase distribution was converted into an effective resistivity distribution of the ground using each of the four resistivity mixing models. From the effective resistivity model, an apparent resistivity response was forward calculated and compared to time-lapse field apparent resistivity measurements from a permafrost monitoring field site. The performance metrics were i) the root mean square error between the forward-calculated and field-measured apparent resistivities throughout the freeze-thaw season, ii) the percentage of field apparent resistivity data explained by each resistivity model, and iii) the plausibility of the calibrated model parameter estimates. We found that despite different current conducting mechanisms involved in each of the resistivity mixing model formulations, the quantitative performance of the four evaluated models was very similar. The four models typically reproduced the field-measured resistivity variations within one to two standard deviations (STD) of the field measurements, depending on the time of the year and depth in the soil profile. In the active layer, the Archie-M model most consistently reproduced the field data within 1 STD throughout the freezing and frozen periods of the year (September – May). Meanwhile, the GM best matched the actual values of resistivities during freezing. The GM also rec
电阻率混合模型将地层材料的孔隙度、相组成和比电阻率与其体积(有效)电特性联系起来。这些模型通常用于计算地球物理测井记录中的碳氢化合物饱和度。在永冻土监测应用中,它们被用来将地层电响应与其相组成联系起来,重点是未冻结的水与冰的含量,并从重复的电阻率采集中推导出地层冰含量的变化。这种定量解释依赖于混合模型在不同于其推导背景下的有效性。为了提高基于重复电阻率测量的永久冻土预报的可靠性,我们对四种选定的电阻率混合模型公式进行了验证:i) 原始阿奇定律;ii) 阿奇定律与冰含量相关的胶结指数 m(阿奇-M);iii) 阿奇定律对多导电相的修正(阿奇-N);以及 iv) 几何平均模型(GM)。模型应用的背景是根据间接(地球物理)、原位延时电阻率测量,对经历冻融循环的天然细粒土壤进行永久冻土监测和命运预测。校准电阻率模型的目的是从原位电阻率测量中得出地层的相组成,其定量可靠性是可以接受的,特别是在冰和含水量的数量和变化方面。在我们的验证框架中,使用四种电阻率混合模型中的每一种,将每日随温度变化的土壤相分布转换为地面的有效电阻率分布。根据有效电阻率模型,正向计算视电阻率响应,并与冻土监测现场的延时现场视电阻率测量结果进行比较。性能指标包括:i) 在整个冻融季节,前向计算的视电阻率与现场测量的视电阻率之间的均方根误差;ii) 每个电阻率模型所解释的现场视电阻率数据的百分比;iii) 校准模型参数估计的可信度。我们发现,尽管每种电阻率混合模型公式中涉及的电流传导机制不同,但四个评估模型的定量性能非常相似。根据不同的时间和土壤剖面深度,这四个模型对实地测量电阻率变化的再现通常在实地测量值的一到两个标准差(STD)范围内。在活动层中,Archie-M 模型在一年中的冻结期和冰冻期(9 月至 5 月)最稳定地再现了实地数据,误差不超过 1 个标准差。同时,GM 与冻结期间的电阻率实际值最为吻合。全球机制还恢复了三个模型层的孔隙率,接近钻孔样本测量的真实值。所有测试模型在准确模拟解冻期方面都遇到了挑战--高估了-5 ℃至-2 ℃温度范围内的电阻率,低估了-2 ℃至解冻点之间的电阻率。因此,对模型的选择应取决于特定应用的具体情况,如可用的校准数据、需要解决的参数或地面特性、建模框架的灵敏度等。可能需要对多个电阻率混合模型进行特定应用验证,并对所选电阻率模型的性能进行量化。此外,还应研究使用不同混合模型和含水量参数的可能性,以充分解决复杂的地面电阻率结构和冻土层典型的相变过程。
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引用次数: 0
Deep anomaly localization using surface-borehole TEM and its application in the Wulong Gold deposit 利用地表钻孔 TEM 进行深部异常定位及其在乌龙金矿床中的应用
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-19 DOI: 10.1016/j.jappgeo.2024.105577
Qingquan Zhi , Junjie Wu , Xingchun Wang , Xiaohong Deng
The localization of deep anomalies is a crucial geophysical topic. Surface-borehole transient electromagnetic method (TEM) offers advantages over traditional surface TEM method, including reduced interference from the ground and enhanced resolution capabilities for deep-seated local anomalies. In this study, the localization of deep anomalies was conducted using surface-borehole TEM methods. Based on the equivalence between the pure anomaly field generated by the anomaly body and the electromagnetic field generated by eddy current loops, the calculation of the pure anomaly field was achieved. The extraction of the pure anomaly field was accomplished through fitting the transient electromagnetic response over a large spatial range. By fitting the pure anomaly field with the eddy current loop field, the geometric parameters of the anomaly body were determined, which enabling anomaly localization. The effectiveness of the proposed method was evaluated through synthetic example and demonstrated through its application in the Wulong Gold Mine area. The results showcase the localization of anomalies exceeding a depth of 2800 m using surface-borehole TEM methods, highlighting their superior resolution capabilities compared to the surface TEM methods. Comprehensive well logging and downhole geochemical surveys indicate that the anomaly localized using surface-borehole TEM methods hold multi-metallogenic prospects, including Cu, Pb, Zn, Au, and Ag, presenting significant research value and potential economic benefits.
深层异常定位是一个重要的地球物理课题。地表-钻孔瞬变电磁法(TEM)与传统的地表 TEM 法相比,具有减少地面干扰、提高深层局部异常分辨率等优势。本研究采用表面-钻孔 TEM 方法对深层异常点进行定位。根据异常体产生的纯异常场与涡流环产生的电磁场之间的等价关系,实现了纯异常场的计算。纯异常场的提取是通过在大空间范围内拟合瞬态电磁响应来实现的。通过将纯异常场与涡流环场拟合,确定了异常体的几何参数,从而实现了异常定位。通过合成实例对所提方法的有效性进行了评估,并在武隆金矿区域进行了应用示范。结果表明,使用地表-井眼 TEM 方法定位的异常深度超过 2800 米,与地表 TEM 方法相比具有更高的分辨率。全面的测井和井下地球化学调查表明,利用地面-井眼 TEM 方法定位的异常蕴藏着多种成矿前景,包括铜、铅、锌、金和银,具有重要的研究价值和潜在的经济效益。
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引用次数: 0
A novel bipolar half-sine current transmitter for helicopter transient electromagnetic surveying 用于直升机瞬态电磁测量的新型双极半正弦电流发射器
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-19 DOI: 10.1016/j.jappgeo.2024.105578
Dong Zhang , Yiming Zhang , Xuhong Wang , Xin Wu
As a core component of a Helicopter Transient Electromagnetic (HTEM) system, the current transmitter determines the primary field. In this paper, a novel bipolar half-sine current transmitter is proposed and analyzed in detail. The Non-dominated Sorting Genetic Algorithm II (NSGA-II) and COMSOL electromagnetic simulation software are employed to optimize the parameters and structure of the pulsed current-generating coil to minimize the weight and maximize the dipole moment under a specified power. A two-stage resonant pulsed current source circuit is designed to reduce conduction losses and improve transmission efficiency. The charging resonant circuit and the transmitting resonant circuit alternately operate to generate a bipolar half-sine waveform pulsed current with an adjustable peak value. A damping resistor is used to suppress turn-off overshoot of the pulsed current. A prototype is constructed and tested in a field experiment. The transmitting moments of the HTEM system exceed 1 MAm2 at all three base frequencies, with the pulsed current-generating coil consuming 2.8 kW of power and weighing only 229.2 kg. The experimental results closely align with the theoretical calculations. The field exploration results confirm that the proposed current transmitter generates high-quality current waveforms and has high stability, significantly enhancing the HTEM system's detection capability.
作为直升机瞬态电磁(HTEM)系统的核心部件,电流发射器决定着主磁场。本文提出并详细分析了一种新型双极半正弦电流发射器。本文采用非支配排序遗传算法 II(NSGA-II)和 COMSOL 电磁仿真软件来优化脉冲电流发生线圈的参数和结构,以在指定功率下实现重量最小化和偶极矩最大化。设计了一个两级谐振脉冲电流源电路,以减少传导损耗并提高传输效率。充电谐振电路和发射谐振电路交替工作,产生峰值可调的双极性半正弦波脉冲电流。阻尼电阻用于抑制脉冲电流的关断过冲。我们制作了一个原型,并在现场实验中进行了测试。HTEM 系统在所有三个基频的发射力矩均超过 1 MAm2,脉冲电流发生线圈的功率消耗为 2.8 kW,重量仅为 229.2 kg。实验结果与理论计算结果非常吻合。现场勘探结果证实,所提出的电流发射器能产生高质量的电流波形,并且具有很高的稳定性,大大提高了 HTEM 系统的探测能力。
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引用次数: 0
Strong motion recording baseline drift recognition based on CNN-LSTM 基于 CNN-LSTM 的强运动记录基线漂移识别
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-19 DOI: 10.1016/j.jappgeo.2024.105574
Wenheng Guo , Runjie Zhang , Maofa Wang , Baofeng Zhou , Yue Yin , Yue Zhang
Strong motion records, as one of the important means to obtain earthquake information and understand the nature of earthquakes, provide a scientific basis for earthquake prediction and disaster prevention and mitigation. However, records that contain baseline drift can degrade the quality of the data and affect subsequent studies. In this paper, a baseline drift identification model based on convolutional neural networks and long short-term memory algorithms is proposed for identifying records containing baseline drift from strong motion records. To improve the accuracy of the model, Bayesian optimization is used to optimize the hyperparameters of the model. Using the strong motion records from the 1999 Taiwan Chi-Chi earthquake, we constructed a dataset and divided the data into two categories: high-quality records and low-quality records. The experimental results show that the proposed baseline drift recognition model can effectively identify baseline drift records, with an accuracy of 83 % and an AUC value of 0.847. It also demonstrates good generalization performance on cross-domain test sets composed of data from the Japan KiK-net and European ESM databases. Compared to other models, the recognition performance of the model in this paper is superior.
强震记录作为获取地震信息、了解地震本质的重要手段之一,为地震预测和防灾减灾提供了科学依据。然而,含有基线漂移的记录会降低数据质量,影响后续研究。本文提出了一种基于卷积神经网络和长短期记忆算法的基线漂移识别模型,用于从强震记录中识别含有基线漂移的记录。为了提高模型的准确性,采用贝叶斯优化法对模型的超参数进行了优化。我们利用 1999 年台湾池芝澳地震的强震记录构建了一个数据集,并将数据分为两类:高质量记录和低质量记录。实验结果表明,所提出的基线漂移识别模型能有效识别基线漂移记录,准确率为 83%,AUC 值为 0.847。在由日本 KiK-net 和欧洲 ESM 数据库数据组成的跨领域测试集上,该模型也表现出良好的泛化性能。与其他模型相比,本文模型的识别性能更为出色。
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引用次数: 0
Site response measurements and implications for soil deformation using geophysical and geotechnical characterization of Djen-Djen Port, Jijel, Northeast Algeria 利用地球物理和岩土技术特征对阿尔及利亚东北部吉杰勒 Djen-Djen 港进行现场响应测量及其对土壤变形的影响
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-17 DOI: 10.1016/j.jappgeo.2024.105568
Sarra Zeroual , Assia Bouchelouh , Fares Kessasra , El Hadi Oubaiche , Rabah Bensalem , Abdelhak Hattab , Djamel Machane
This paper describes the concept used to develop a methodology and an integrated approach based on the ambient vibration horizontal-to-vertical spectral ratio (HVSR) combined with geotechnical analysis for assessing soil deformations observed in Djen-Djen port located near Jijel-City (north-east Algeria).
140 ambient vibrations recording were carried out to generate a spatial distribution map of the HVSR curves, seismic vulnerability index (Kg) and the ground shear strain GSS-(γ) value distribution maps. The spatial distribution of Kg and GSS-(γ) values estimated correlates well with both the geological units and soil deformations in the study area. In addition, the mapping of the spatial distribution of the HVSR curves delineates six distinct zones, thus reflecting the sensitivity of the HVSR peak amplification factor with the compactness and technical properties of the soil.
The qualitative and quantitative analysis developed in this study made it possible to characterize the embankments, settlement, and liquefaction observed at the port of Djen-Djen in eastern Algeria. This paper shows that the HVSR method is a useful and promising technique for studying soil settlement and liquefaction. The Kg and GSS maps can be used as a guide to implementation of geotechnical tests before any conventional study and as well to identify sites that are vulnerable to deformation for seismic hazard reduction.
本文介绍了在环境振动水平-垂直谱比(HVSR)基础上,结合岩土力学分析,开发评估吉杰尔市(阿尔及利亚东北部)附近 Djen-Djen 港口土壤变形的方法和综合方法所使用的概念。估算出的 Kg 和 GSS-(γ) 值的空间分布与研究区域的地质单元和土壤变形都有很好的相关性。此外,HVSR 曲线的空间分布图划分出六个不同的区域,从而反映出 HVSR 峰值放大系数对土壤密实度和技术特性的敏感性。本文表明,HVSR 方法是研究土壤沉降和液化的一种有用且有前途的技术。在进行任何常规研究之前,Kg 和 GSS 地图可用作实施岩土测试的指南,也可用于确定易受变形影响的地点,以减少地震危害。
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引用次数: 0
Optimising Ground Penetrating Radar data interpretation: A hybrid approach with AI-assisted Kalman Filter and Wavelet Transform for detecting and locating buried utilities 优化探地雷达数据判读:采用人工智能辅助卡尔曼滤波和小波变换的混合方法探测和定位埋地公用设施
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-15 DOI: 10.1016/j.jappgeo.2024.105567
Arasti Afrasiabi , Asaad Faramarzi , David Chapman , Alireza Keshavarzi
Ground Penetrating Radar (GPR) is widely used for detecting buried utilities, but data interpretation remains challenging due to noise and clutter. Although various methods exist for processing GPR data, the Kalman Filter (KF) has been underutilised despite its strength as an estimator. Traditional KF-based algorithms in GPR studies often rely on chi-squared hypothesis testing, which requires expert-defined thresholds and can lead to biased or uncertain outcomes. This paper introduces a novel KF-based framework that addresses these limitations. The framework employs Kalman Filters for noise reduction, with an optimisation algorithm based on a genetic algorithm to fine-tune KF input parameters. A Normalised Innovation Squared (NIS) parameter is used to generate an NIS signal function for identifying anomalies. Additionally, discrete wavelet transforms are applied to the NIS signal function for anomaly detection and localisation, using varying decomposition levels and vanishing moments. Results demonstrate a proportional relationship between wavelet decomposition levels, selected wavelets, and the detection rates of true and false positives. Statistical analysis using receiver operating characteristic curves shows that the optimal detection rate for all tested wavelets occurs at decomposition levels 5 and 6. This framework enhances GPR data interpretation with minimal user interaction, representing a step forward toward autonomy in GPR data processing and interpretation.
地面穿透雷达(GPR)被广泛用于探测地下公用设施,但由于噪声和杂波的影响,数据解读仍具有挑战性。虽然处理 GPR 数据的方法多种多样,但卡尔曼滤波器(KF)作为一种估算器,尽管有其优势,却一直未得到充分利用。在 GPR 研究中,基于 KF 的传统算法通常依赖于卡方假设检验,这需要专家定义的阈值,并可能导致有偏差或不确定的结果。本文介绍了一种基于 KF 的新型框架,以解决这些局限性。该框架采用卡尔曼滤波器进行降噪,并采用基于遗传算法的优化算法对 KF 输入参数进行微调。归一化创新平方(NIS)参数用于生成用于识别异常的 NIS 信号函数。此外,利用不同的分解水平和消失矩,对 NIS 信号函数进行离散小波变换,以进行异常检测和定位。结果表明,小波分解水平、所选小波与真假阳性检测率之间存在比例关系。利用接收器工作特性曲线进行的统计分析显示,所有测试小波的最佳检测率出现在分解级别 5 和 6。该框架以最少的用户交互增强了 GPR 数据判读,标志着 GPR 数据处理和判读向自主化迈进了一步。
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引用次数: 0
Magnetic diagnosis model for heavy metal pollution in beach sediments of Qingdao, China 中国青岛海滨沉积物重金属污染磁力诊断模型
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-14 DOI: 10.1016/j.jappgeo.2024.105553
Wang Yong-Hong , Huang Yi-Heng , Liang Wei-Qiang
Magnetic techniques have been widely used in recent decades to determine heavy metal pollution in sediments due to their high sensitivity to magnetic particles and considerable measurement convenience. Beaches are usually greatly influenced by human activities, but pollution problems such as heavy metal pollution due to sewage discharge, nearby factories, and garbage disposal have reduced the tourism value and ecological environmental quality of beaches. In this study, three beaches in Qingdao city were chosen as examples, and a magnetic diagnostic model for heavy metal pollution in beach sediments was established using statistical methods. The results showed that beach No. 1 in Qingdao was not polluted, while the pollution level of beach No. 2 was lower than that of beach No. 3. Beach No. 2 exhibited slight Cr and Zn pollution and slight Fe enrichment, while beach No. 3 exhibited slight to severe Cr, Ni, and Zn pollution and severe Fe enrichment. The statistical model results indicated that χ, saturation isothermal remanent magnetization (SIRM), SOFT, and χARM are more suitable for establishing magnetic diagnostic models, and the pollution level, pollution source and diffusion range of heavy metal elements could be detected with this model. The main causes of pollution are sewage outlets and the disposal of artificial coal ash. When the magnetic susceptibility value of the 0.063–0.125 mm particle size fraction of Qingdao beach sediments is greater than 6000 × 10−8 m3kg−1, attention should be given to possible contamination by heavy metals. In this study, we revealed that environmental magnetic methods can be employed to effectively determine the pollution level, source, and diffusion of heavy metals in beach sediments, which can facilitate the management of heavy metals and other pollutants in beach sediments and ecological environmental protection.
近几十年来,磁性技术因其对磁性颗粒的高灵敏度和相当大的测量便利性而被广泛用于测定沉积物中的重金属污染。海滩通常受人类活动影响较大,但由于污水排放、附近工厂、垃圾处理等造成的重金属污染问题,降低了海滩的旅游价值和生态环境质量。本研究选取青岛市的三个海滩为例,利用统计学方法建立了海滩沉积物重金属污染磁性诊断模型。结果表明,青岛 1 号海滩未受污染,2 号海滩的污染程度低于 3 号海滩。2 号海水浴场表现为轻度铬、锌污染和轻度铁富集,3 号海水浴场表现为轻度至重度铬、镍、锌污染和重度铁富集。统计模型结果表明,χ、饱和等温剩磁(SIRM)、SOFT 和 χARM 更适合建立磁诊断模型,利用该模型可检测重金属元素的污染程度、污染源和扩散范围。污染的主要原因是排污口和人工煤灰的处理。当青岛海滨沉积物 0.063-0.125 mm 粒径部分的磁感应强度值大于 6000×10-8 m3kg-1 时,应注意可能受到重金属污染。本研究揭示了利用环境磁法可以有效地确定海滩沉积物中重金属的污染程度、来源和扩散情况,有利于海滩沉积物中重金属等污染物的治理和生态环境保护。
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引用次数: 0
Modified approach to estimate effective porosity using density and neutron logging data in conventional and unconventional reservoirs 利用密度和中子测井资料估算常规和非常规储层有效孔隙度的改进方法
IF 2.2 3区 地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY Pub Date : 2024-11-14 DOI: 10.1016/j.jappgeo.2024.105571
Muhammad Abid , Jing Ba , Uti Ikitsombika Markus , Zeeshan Tariq , Syed Haroon Ali
Porosity is a critical petrophysical parameter that governs storage capacity in reservoirs. Despite the introduction of various techniques to assess pore structure, the complexity of rock components and the wide range of pore types have led to limitations in accurately evaluating porosity, particularly in clay-dominant reservoirs. Discrepancies and inconsistencies remain among different analytical calculation methods. Determining porosity using neutron and density logs is especially challenging in the presence of clay minerals and hydrocarbon saturation, particularly gas. Gas saturation reduces rock density, while in clay-dominant formations, neutron logs often indicate excessively high porosity due to the water content in clays. The impact of clay-bound water on rock porosity is still not fully accounted for. This study proposes a modified method for estimating porosity in both conventional and unconventional reservoirs, addressing the effect of clay-bound water on porosity calculations. The proposed method incorporates the rock's composition through its response observed in the neutron and density logs. Analytical equations are formulated to account for the influence of clay-bound water on these logs, and porosity is estimated. To validate the methodology, it was applied to two wells in organic shale reservoirs and one well in a conventional reservoir. The proposed porosity estimation method produced results that closely aligned with previously established methods, demonstrating consistency across all three wells with minimal deviations. This method offers broad applicability for exploration and exploitation in both conventional and unconventional reservoirs.
孔隙度是决定储层储集能力的关键岩石物理参数。尽管引入了各种评估孔隙结构的技术,但岩石成分的复杂性和孔隙类型的多样性导致了准确评估孔隙度的局限性,特别是在以粘土为主的储层中。不同的分析计算方法之间存在差异和不一致。在存在粘土矿物和碳氢化合物饱和度(特别是天然气)的情况下,使用中子和密度测井来确定孔隙度尤其具有挑战性。气体饱和度降低了岩石密度,而在以粘土为主的地层中,中子测井往往表明,由于粘土中的水分含量,孔隙度过高。粘土结合水对岩石孔隙度的影响仍未得到充分解释。该研究提出了一种改进的方法来估计常规和非常规储层的孔隙度,解决了粘土结合水对孔隙度计算的影响。所提出的方法通过中子和密度测井观察到的岩石响应来结合岩石成分。建立了分析方程,以解释粘土结合水对这些测井曲线的影响,并估计了孔隙度。为了验证该方法,将其应用于有机页岩储层的两口井和常规储层的一口井。所提出的孔隙度估算方法的结果与之前建立的方法非常一致,在所有三口井中都显示出最小偏差的一致性。该方法对常规和非常规油藏的勘探开发具有广泛的适用性。
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引用次数: 0
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Journal of Applied Geophysics
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