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Slope reliability assessment using an innovative critical failure path approach 采用创新的关键故障路径法评估斜坡可靠性
Pub Date : 2024-08-09 DOI: 10.3389/feart.2024.1428309
Xiyang Tang, Chen Chen, Dan Shan, Pengtao Zhang, Jianghan Xue
Slope instability, driven by factors such as rainfall, seismic activity, and human influence, presents a pervasive hazard worldwide. Timely assessment of slope stability and accurate identification of its most critical slip surface are important for slope safety early warning and management. Currently, for the slope reliability analysis by the strength reduction method (SRM), the critical failure path is approximately determined through visualization techniques, which is not sufficiently precise. Therefore, this study proposes a critical failure search method based on SRM for slope reliability analysis, aiming to accurately identify the critical slip surface. The critical failure path is considered as the path with the maximum plastic dissipative energy density (PDED) and is searched in the constructed weighted graph based on the dissipated energy of the slope. This proposed method is further applied with an engineering slope to find the critical failure path and assess its reliability during and after construction. The searched critical failure path lies within the approximate range obtained through conventional visualization methods. Finally, a reliability prediction model consisting of time, rainfall, and deformation component is further constructed, which allows rapid estimation of the slope reliability through available monitor data. The results of reliability analysis indicate that construction disturbances have a significant impact on slope stability, along with other factors such as rainfall and creep.
受降雨、地震活动和人为影响等因素的影响,斜坡不稳定性在全球范围内普遍存在。及时评估斜坡稳定性并准确识别其最关键的滑动面对于斜坡安全预警和管理非常重要。目前,采用强度降低法(SRM)进行边坡可靠性分析时,临界破坏路径是通过可视化技术近似确定的,不够精确。因此,本研究提出了一种基于 SRM 的边坡可靠性分析临界破坏搜索方法,旨在精确确定临界滑移面。临界破坏路径被认为是塑性耗散能量密度(PDED)最大的路径,并根据斜坡的耗散能量在构建的加权图中进行搜索。该方法进一步应用于工程边坡,以找到临界失效路径,并评估其在施工期间和施工后的可靠性。搜索到的临界失效路径在传统可视化方法得到的近似范围内。最后,进一步构建了一个由时间、降雨量和变形成分组成的可靠性预测模型,该模型可通过现有的监测数据快速估算斜坡的可靠性。可靠性分析结果表明,施工干扰以及降雨和蠕变等其他因素对斜坡稳定性有重大影响。
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引用次数: 0
Editorial: Women in science: geohazards and georisks 2022 社论:科学界的女性:地质灾害和地质风险 2022 年
Pub Date : 2024-08-09 DOI: 10.3389/feart.2024.1469867
Elisa Zuccolo, Veronica Pazzi
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引用次数: 0
Monitoring the Hunga Volcano (Kingdom of Tonga) starting from the unrests of 2014/2015 to the 2021/2022 explosion with the Sentinel 1-2 and Landsat 8-9 satellites 利用哨兵 1-2 号卫星和大地遥感卫星 8-9 号卫星监测洪加火山(汤加王国)从 2014/2015 年动乱到 2021/2022 年爆炸的情况
Pub Date : 2024-08-08 DOI: 10.3389/feart.2024.1373539
Carla Braitenberg
This study explores the dynamic evolution of the Hunga Volcano in the Kingdom of Tonga and covers two volcanic unrests, focusing on the creation and subsequent disappearance of a new island between Hunga Tonga (HT) and Hunga Ha'apai (HH) between 2013 and 2023. The island expanded in 2015 and vanished in January 2022 due to a massive eruption (VEI = 6), featuring a 57 km high volcanic cloud and generating multiple tsunamis that caused damage across the Pacific Ocean. Utilizing remote sensing techniques, including multispectral imaging from Sentinel 2, Landsat 8-9, and synthetic aperture radar (SAR) imaging from Sentinel 1, the research employs a supervised random forest classification algorithm to individuate the changing subaerial surface area of the volcano. This approach documents size variations in the islands, particularly during weeks surrounding two volcanic unrests. The classifier, trained on nearly cloud-free multispectral images, automatically delineates surface area changes over the years. The temporal resolution of area change, limited to images with less than 5% cloudiness, encompasses about 50% of Landsat and 20% of Sentinel 2 images between 2013 and 2023, selected from 739 available images. The multispectral observations are complemented by 215 Sentinel 1 SAR images, penetrating clouds, though with limited bands. Despite higher noise, the classifier on Sentinel 1 successfully distinguishes land from ocean. Sentinel 1 observations, starting in 2014, cover the volcano unrest of 2014/2015. Earth Engine, a cloud computing data facility, is used for processing. Analysis indicates a slight decrease in the area change post-2015 island formation and identifies the disappearance of the island bridge connecting HT and HH, along with two smaller islands south of HT and HH in 2022. The 2022 explosion is preceded by an increase in island area in the weeks before the eruption. Global satellite coverage could automatically detect changes in oceanic areas and distinguish water from new volcanic islands, offering a means of identifying volcanic unrests and documenting their evolution.
本研究探讨了汤加王国洪加火山的动态演变,涵盖了两次火山动荡,重点是 2013 年至 2023 年期间在洪加-汤加(HT)和洪加-哈帕伊(HH)之间一个新岛屿的形成和随后的消失。该岛在 2015 年扩大,并于 2022 年 1 月因大规模喷发(VEI = 6)而消失,喷发出 57 千米高的火山云,并引发多次海啸,给整个太平洋造成破坏。这项研究利用遥感技术,包括哨兵 2 号、大地遥感卫星 8-9 号的多光谱成像和哨兵 1 号的合成孔径雷达成像,采用了一种有监督的随机森林分类算法,以确定火山不断变化的地表下面积。这种方法记录了岛屿的大小变化,尤其是在两次火山动乱前后的几周内。分类器是在几乎无云的多光谱图像上训练出来的,能自动划分出多年来表面积的变化。面积变化的时间分辨率仅限于云量小于 5%的图像,包括从 739 幅可用图像中选出的 2013 年至 2023 年期间约 50% 的 Landsat 图像和 20% 的 Sentinel 2 图像。215 幅 "哨兵 1 号 "合成孔径雷达图像可穿透云层,但波段有限,为多光谱观测提供了补充。尽管噪声较高,但哨兵 1 号的分类器仍能成功区分陆地和海洋。哨兵 1 号的观测始于 2014 年,涵盖了 2014/2015 年的火山动乱。使用云计算数据设施 "地球引擎 "进行处理。分析表明,2015 年后岛屿形成的面积变化略有减少,并确定连接 HT 和 HH 的岛桥以及 HT 和 HH 南部的两个小岛将于 2022 年消失。2022 年爆发前几周,岛屿面积有所增加。全球卫星覆盖可以自动检测海洋区域的变化,区分水域和新火山岛,为识别火山动荡和记录其演变提供了一种方法。
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引用次数: 0
Editorial: Citizen science and climate services in cities: current state, new approaches and future avenues for enhancing urban climate resilience 社论:城市中的公民科学和气候服务:提高城市气候复原力的现状、新方法和未来途径
Pub Date : 2024-08-08 DOI: 10.3389/feart.2024.1461334
C. Schuetze, U. Koedel, Thora M. Herrmann, Christine Liang, Peter Dietrich
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引用次数: 0
Construction and preliminary analysis of landslide database triggered by heavy storm in the parallel range-valley area of western Chongqing, China, on 8 June 2017 2017年6月8日中国重庆西部平行岭谷区暴雨引发的滑坡数据库构建与初步分析
Pub Date : 2024-08-08 DOI: 10.3389/feart.2024.1420425
Jielin Liu, Chong Xu
On 8 June 2017, a heavy storm struck the parallel ridge-valley area of western Chongqing, resulting in serious urban waterlogging and landslides, which led to severe impacts on infrastructure and damage to private property. Based on high-resolution optical satellite images, this paper comprehensively identified the landslides triggered by this rainfall event, and established a corresponding landslide database. The database takes the landslide area density and landslide number density as the main indicators, and combines the lithology characteristics to analyze the spatial distribution of landslides. The results show that this event triggered 487 landslides in an area of 583 km2, involving an area of about 485,587 m2, accounting for about 0.083% of the study area. The average landslide number density is 0.84 num/km2, the highest value of landslide number density can reach 55.6 num/km2, and the maximum landslide area density is about 6.4%. These landslides are mainly distributed in the southern foothills of the Huaying Mountain, especially in the weak interlayer lithology area. The database provides scientific reference and data support for exploring the mechanism of landslides in western Chongqing and reducing the risk of landslide disasters under the background of rapid development of local society.
2017年6月8日,重庆西部平行山脊-山谷地区遭受暴雨袭击,造成严重的城市内涝和山体滑坡,导致基础设施受到严重影响,私人财产遭受严重损失。本文基于高分辨率光学卫星图像,全面识别了此次降雨事件引发的滑坡,并建立了相应的滑坡数据库。该数据库以滑坡面积密度和滑坡数量密度为主要指标,结合岩性特征,分析滑坡的空间分布。结果表明,此次事件在 583 km2 的区域内引发了 487 次滑坡,涉及面积约 485 587 m2,约占研究区域的 0.083%。平均滑坡数量密度为 0.84 个/平方公里,滑坡数量密度最高值可达 55.6 个/平方公里,最大滑坡面积密度约为 6.4%。这些滑坡主要分布在华宁山南麓,特别是层间岩性较弱的区域。该数据库为探索重庆西部滑坡发生机理、降低当地社会快速发展背景下的滑坡灾害风险提供了科学参考和数据支持。
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引用次数: 0
Editorial: Prevention, mitigation, and relief of compound and chained natural hazards 社论:复合型和连锁型自然灾害的预防、减轻和救助
Pub Date : 2024-07-26 DOI: 10.3389/feart.2024.1462471
Chong Xu, Qi Yao, Xiangli He, Wenwen Qi, S. Meena, Wentao Yang, Liam Taylor
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引用次数: 0
Trace element zoning of colorless beryl from spodumene pegmatites of Pashki deposit (Nuristan province, Afghanistan) 帕什基矿床(阿富汗努里斯坦省)伟晶岩中无色绿柱石的微量元素分带
Pub Date : 2024-07-25 DOI: 10.3389/feart.2024.1432222
S. Skublov, N. Hamdard, Mikhail A. Ivanov, V. Stativko
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引用次数: 0
DiffSim: a user-friendly tool for precise magmatic timescale determination and error propagation via major element diffusion chronometry in magmatic phases DiffSim:通过岩浆相中主要元素扩散计时法精确确定岩浆时间尺度和误差传播的用户友好型工具
Pub Date : 2024-07-16 DOI: 10.3389/feart.2024.1431516
Eduardo Morgado, Daniel J. Morgan
Diffusion chronometry is a technique gaining interest in the scientific community related to volcanology and petrology; however, modelling can be challenging for non-expert users. Here, we present DiffSim, a user-friendly standalone freeware that allows users to calculate magmatic timescales simulating 1D diffusion of major elements in olivine, orthopyroxene, titanomagnetite, and melt (inclusions). The freeware works solving the Fick’s second law equation (for both Cartesian and spherical polar coordinates, depending on the phase) using finite differences through the Crank-Nicolson method. Users must specify the initial composition vs. distance profile, the time resolution, and the intensive conditions (such as temperature, pressure, and oxygen fugacity). For orthorhombic phases, such as olivine and orthopyroxene, users must also specify the plunge and the trend of the (001)-axis and the angle traverse of the 2D section being studied. The best-fitting profile, comparing the natural (measured) and the modelled (calculated) profiles, is obtained using the least-squares fitting method in accordance with the total time specified by the user for performing the diffusion modelling. To determine the uncertainties of the timescale calculation, DiffSim propagates errors based on the uncertainties associated with each intensive condition and the experimental diffusivity measurements. DiffSim is available as executable freeware, allowing researchers and students to use diffusion chronometry to elucidate information about crustal processes with ease and precision.
扩散时间测定法是一种与火山学和岩石学有关的科学界越来越感兴趣的技术;然而,对于非专业用户来说,建模可能具有挑战性。在此,我们介绍 DiffSim,这是一款用户友好型独立免费软件,允许用户通过模拟橄榄石、正长石、榍石和熔体(包裹体)中主要元素的一维扩散来计算岩浆时标。该免费软件通过 Crank-Nicolson 方法使用有限差分法求解菲克第二定律方程(笛卡尔坐标和球极坐标,取决于相位)。用户必须指定初始成分与距离曲线、时间分辨率和强化条件(如温度、压力和氧富集度)。对于橄榄石和正霞石等正方体相,用户还必须指定所研究的二维截面的(001)轴和角度横截面的倾角和趋势。根据用户指定的执行扩散建模的总时间,使用最小二乘拟合方法,比较自然(测量)剖面和建模(计算)剖面,获得最佳拟合剖面。为了确定时间刻度计算的不确定性,DiffSim 会根据与每个强化条件和实验扩散率测量相关的不确定性传播误差。DiffSim 是可执行的免费软件,研究人员和学生可利用扩散计时法轻松、精确地阐明有关地壳过程的信息。
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引用次数: 0
An EGF technique to infer the source parameters of a circular crack growing at a variable rupture velocity 推断以可变断裂速度生长的圆形裂缝源参数的 EGF 技术
Pub Date : 2024-07-16 DOI: 10.3389/feart.2024.1428167
Salvatore de Lorenzo, Maddalena Michele
Circular crack models with a constant rupture velocity struggle to effectively model both the amplitude and duration of first P-wave pulses generated by small magnitude seismic events. Assuming a constant rupture velocity is unphysical, necessitating a deceleration phase in the rupture velocity to uphold the causality of the healing process. Moreover, a comprehensive failure model might encompass an initial nucleation phase, typically characterized by an increase of the initial rupture velocity. Studies have demonstrated that quasi-dynamic circular crack models featuring variable rupture velocities can accurately model the shape of the observed first P-wave pulse. Based on these principles, an Empirical Green’s function (EGF) approach was previously formulated to estimate the source parameters of small magnitude earthquakes, called MAIN. In addition to determine the source radius and stress drop, this method also enables the inference of the temporal evolution of rupture velocity. However, this method encounters difficulties when the noise-to-signal ratio in the recordings of smaller earthquakes used as EGF exceeds 5%, a common situation when employing regional-scale recordings of small-magnitude earthquakes as EGF. Through synthetic tests, we demonstrated that, in such instances, the problem of this technique is that the alignment between the onset of P waves of EGF and MAIN is not rightly recovered after the initial inversion step. Consequently, a novel inversion method has been developed to address this issue, enabling the identification of the optimal alignment of P-wave arrivals in EGF and MAIN across all stations. A Bayesian statistical approach is proposed to meticulously investigate the solutions of model parameters and their correlations. Using the new technique on a small magnitude earthquake (ML = 3.3) occurred in Central Italy enabled us to identify the most likely rupture models and examine the issue of correlation among model parameters. Application of Occam’s Razor Principle suggests that, for the investigated event, a circular crack model should be favored over a heterogeneous rupture model.
具有恒定破裂速度的圆形裂缝模型难以有效模拟小震级地震事件产生的第一 P 波脉冲的振幅和持续时间。假设恒定的破裂速度是不符合实际情况的,这就需要在破裂速度上有一个减速阶段,以维护愈合过程的因果关系。此外,一个全面的故障模型可能包含一个初始成核阶段,其典型特征是初始破裂速度的增加。研究表明,以可变断裂速度为特征的准动态圆形裂缝模型可以准确模拟观察到的第一个 P 波脉冲的形状。根据这些原理,以前制定了一种经验格林函数(EGF)方法来估计小震级地震的震源参数,称为 MAIN。除了确定震源半径和应力降之外,这种方法还能推断断裂速度的时间演变。然而,当用作 EGF 的较小地震记录的噪声信号比超过 5%(这是使用区域尺度小震记录作为 EGF 时的常见情况)时,该方法就会遇到困难。通过合成测试,我们证明了在这种情况下,该技术的问题是在初始反演步骤之后,EGF P 波的起始点与 MAIN 之间的排列无法正确恢复。因此,我们开发了一种新的反演方法来解决这一问题,从而能够确定所有站点的 EGF 和 MAIN P 波到达的最佳排列。提出了一种贝叶斯统计方法,以仔细研究模型参数及其相关性的解决方案。在意大利中部发生的一次小震级地震(ML = 3.3)中使用新技术,使我们能够确定最有可能的破裂模型,并研究模型参数之间的相关性问题。奥卡姆剃刀原理的应用表明,对于所研究的事件,圆形裂缝模型应优于异质破裂模型。
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引用次数: 0
Building and maintaining a volunteer community: experiences of an image archive 建立和维护志愿者社区:图像档案馆的经验
Pub Date : 2024-07-16 DOI: 10.3389/feart.2024.1328883
Nicole Graf
The ETH-Library’s Image Archive has been using the knowledge of volunteers for over 15 years to identify photographs (aerial images, documentary and scientific photographs, press photography, etc.) correct and improve image metadata or georeference images. The first big challenge in starting so-called crowdsourcing projects is how to find people who might be enthusiastic about such a project. The second big challenge is how to maintain a community and keep it going over a longer period. A variety of experiences, tips as well as do’s and don’ts are discussed in the article.
15 年来,ETH 图书馆的图像档案一直在利用志愿者的知识来识别照片(航空图像、纪实和科学照片、新闻摄影等),纠正和改进图像元数据或图像地理参考。启动所谓众包项目的第一大挑战是如何找到热衷于此类项目的人。第二大挑战是如何维持一个社区并使其长期发展下去。文中讨论了各种经验、技巧以及该做和不该做的事情。
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引用次数: 0
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Frontiers in Earth Science
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