Hasil untuk "Geology"

S. Bachu

Lorraine M. Cahill

The Department of Civil and Environmental Engineering offers a minor program in Geotechnical Engineering. Geotechnical Engineering is traditionally an interdisciplinary field, drawing on elements of geology, geophysics, and the mechanics of fluids and solids. This breadth can be obtained by combining an undergraduate major in physical and mathematical sciences with a minor in Geotechnical Engineering. This minor is suitable for students interested in either professional practice or in graduate studies within the Department of Civil and Environmental Engineering at Berkeley, and elsewhere.

Lingyun Lu, Yueren Xu, Jiacheng Tang et al.

Rapidly obtaining spatial distribution maps of secondary disasters triggered by strong earthquakes is crucial for understanding the disaster-causing processes in the earthquake hazard chain and formulating effective emergency response measures and post-disaster reconstruction plans. On April 3, 2024, a MW 7.4 earthquake struck offshore east of Hualien, Taiwan, China, which triggered numerous coseismic landslides in bedrock mountain regions and severe soil liquefaction in coastal areas, resulting in significant economic losses. This study utilized post-earthquake emergency data from China's high-resolution optical satellite imagery and applied visual interpretation method to establish a partial database of secondary disasters triggered by the 2024 Hualien earthquake. A total of 5 348 coseismic landslides were identified, which were primarily distributed along the eastern slopes of the Central Mountain Range watersheds. In high mountain valleys, these landslides mainly manifest as localized bedrock collapses or slope debris flows, causing extensive damage to highways and tourism facilities. Their distribution partially overlaps with the landslide concentration zones triggered by the 1999 Chi-Chi earthquake. Additionally, 6 040 soil liquefaction events were interpreted, predominantly in the Hualien Port area and the lowland valleys of the Hualien River and concentrated within the IX-intensity zone. Widespread surface subsidence and sand ejections characterized soil liquefaction. Verified against local field investigation data in Taiwan, rapid imaging through post-earthquake remote sensing data can effectively assess the distribution of coseismic landslides and soil liquefaction within high-intensity zones. This study provides efficient and reliable data for earthquake disaster response. Moreover, the results are critical for seismic disaster mitigation in high mountain valleys and coastal lowlands.

Chenxia Li, Yanbing Wang, Jie Yu et al.

Study region: Beijing plain in the eastern of Beijing, China. Study focus: Over the past three decades, more than 2 billion m3 of groundwater have been pumped annually in the Beijing Plain, resulting in approximately 431 km2 of land subsidence of more than 50 mm annually. While most studies have identified a correlation between land subsidence and groundwater overexploitation, quantifying their relationship has been challenging. In this paper, the land subsidence data were obtained based on the persistent scatterer interferometric synthetic aperture radar (PS-InSAR, PSI) and the least square (LS) method. The parameter of inelastic skeletal storativity (Si) of the confined aquifer was used as a quantitative indicator to describe the relationship between land subsidence and groundwater exploitation in the Beijing Plain. New hydrology insights: Moreover, the paper found a robust correlation between groundwater overexploitation and land subsidence in the deep confined aquifer through groundwater monitoring data. From 2005–2016, Si showed a gradual and continuous increase in a specific range. The abnormal change in Si value during 2014–2015 may be associated with the recharge of shallow confined and unconfined aquifers in the Beijing Plain by the South-to-North Water Diversion Project. The Si estimated in the study area can be utilized to accurately deduce the regional water level shifts, thereby aiding in the efficient and sustainable management of groundwater resources.

Tiago B. Ramos, Maria C. Gonçalves, Martinus Th. vanGenuchten

Abstract Soil salinization poses a significant threat to agricultural production in Portugal. Collaborative research spanning three decades with the U.S. Salinity Laboratory in Riverside, California, has been instrumental in advancing our understanding of this issue. This study provides a concise overview of the causes of soil salinization in Portugal, focusing on ongoing efforts to comprehensively address this challenge. Key advancements highlighted in this study encompass the meticulous characterization of soil hydraulic and solute transport parameters, the application of cutting‐edge modeling tools for water flow and solute transport in diverse agricultural systems, and the utilization of innovative proximal and remote sensing methods for mapping soil salinity. Noteworthy results and practical implications of these advancements underscore their relevance in real‐world scenarios. While celebrating these achievements, the study emphasizes the current nature of the ongoing research, highlighting the dynamic landscape of soil salinization. The study underscores the imperative need for further advancements to effectively cope with soil salinization, especially in anticipation of the intensification of agricultural practices and the looming impacts of climate change. This comprehensive overview not only encapsulates past achievements but also sets the stage for future research endeavors in mitigating the pervasive effects of soil salinization on agricultural sustainability in Portugal.

Stephen Wu, Yu Otake, Yosuke Higo et al.

This paper elucidates the challenges and opportunities inherent in integrating data-driven methodologies into geotechnics, drawing inspiration from the success of materials informatics. Highlighting the intricacies of soil complexity, heterogeneity, and the lack of comprehensive data, the discussion underscores the pressing need for community-driven database initiatives and open science movements. By leveraging the transformative power of deep learning, particularly in feature extraction from high-dimensional data and the potential of transfer learning, we envision a paradigm shift towards a more collaborative and innovative geotechnics field. The paper concludes with a forward-looking stance, emphasizing the revolutionary potential brought about by advanced computational tools like large language models in reshaping geotechnics informatics.

Xiaoqing Feng, Bin Ye, Jie He et al.

Sand liquefaction is a process in which the excess pore water pressure of saturated sand soils increases and the effective stress of saturated sand decreases under the action of vibration, resulting in the transition of sand soils from the solid state to the liquid state. In this paper, an underwater sand slope model containing the upper sand slope and the bottom non-liquefied clay layer was designed. The whole process of large deformation of flow liquefaction from the solid state to the liquid state was reproduced by the shaking table test and recorded by the high-definition particle image velocimetry (PIV) equipment. Four main influencing factors: the acceleration amplitude of the shaking table, the frequency of the shaking table, the relative density of the sand slope, and the slope ratio of height and width of the sand slope, were considered. During the test, the dynamic response characteristics of acceleration and excess pore water pressure (EPWP) within the underwater sand slope model were monitored and analyzed in the whole deformation process to reveal the mechanism of the sand liquefaction process and the law of development and provide data support for subsequent research.

Ryleigh Landstra, Ian Winkelstern

Large concentrically laminated carbonate grains (here referred to as pisoids) have been observed sporadically throughout the geological record and in modern environments. Explanations for how these grains form have varied widely in different settings, although microbial effects are often involved. In Ore Lake, a ~1 km2 flow-through lake in southeast Michigan, one to four centimeter oblong calcite pisoids are observed in both lake bottom shallows and mounded as a small spit near the primary outflow. In section mm-scale light and more porous along with and dark and more dense concentric laminations are apparent. Here we use field observations, petrography, water chemistry, and stable isotopes to understand their formation. Measurements of pisoid calcite δ18O and lake water δ18O indicate that precipitation occurs in waters between roughly 19 – 28°C. These warm temperatures imply that pisoid growth happens almost entirely within the summer, contrary to prior work that suggested wintertime precipitation was important. Pisoid δ18O values largely overlap with coexisting lake bivalve values, suggesting that pisoid precipitation is in equilibrium. In contrast, pisoid δ13C is as much as 8 ‰ more positive than bivalve δ13C due to photosynthetic effects. We propose that the laminations in these pisoids arise from different rates of formation within the warm months, rather than large seasonal differences. A decline in lake alkalinity beginning in late spring likely coincides with more rapid growth, with slower growth mediated by cyanobacteria continuing through the summer. This range of observations enables the use of Ore Lake as a potential model for understanding pisoid formation throughout the geological record.

Mahmoud Etman, Abdelmonem Mohamed, Haitham Ayyad et al.

The Egyptian Nile Delta is one of the world's most vital regions owing to its great agricultural, industrial, and economic value. Almost half of Egypt's population resides in this region, which has experienced significant land subsidence during the past decade. The present study evaluates the land deformation rate based on Sentinel-1A C-band synthetic aperture radar imagery on the western part of the Nile Delta. Due to the impact of the earthquake event in crete at magnitude of approximately 6.2 Mw on 19 October 2021, 6 scenes were selected to know the differential interferogram and vertical deformations. In our case study, Sentinel Application Platform processing techniques are applied to 6 Sentinel-1A images on 10 September, 4 October 2021, 13-25 October 2021 and 04-21 November 2021 before and after the occurrence of the earthquake, respectively. Our results show that some places in the western part of Nile Delta region experienced low–medium ground movement. To mitigate the seismic and kinetic effects in the western part of Delta, the construction of large factories near residential areas is discouraged. Moreover, urban expansion should be managed in these regions, and excessive groundwater extraction should be avoided in the arid regions near the western part of Nile delta.

Nur Hayati Hussin, Ismail Yusoff, May Raksmey

Groundwater has supported 70% of the water supply at the Lower Kelantan River Basin (LKRB) since the 1930s and demand for groundwater increases annually. Groundwater has been abstracted from shallow and deep aquifers. However, a comprehensive study on groundwater recharge estimation has never been reported. This study evaluated various methods to quantify recharge rate using chloride mass balance (CMB), water table fluctuation (WTF), temperature–depth profiles (TDP), and groundwater modelling coupled with water balance (GM(WB)). Recharge estimation using CMB, WTF, TDP, and GM(WB) showed high variability within 8% to 68% of annual rainfall. CMB is range from 16% to 68%, WTF 11% to 19%, TDP 8% to 11%, and GM(WB) 7% to 12% of annual rainfall, respectively. At 11%, recharge from GM(WB) was the best method for estimation because the model was constructed and calibrated using locally derived input parameters. GM(WB) is the only method involved with calibration and validation process to reduce the uncertainty. The WTF method based on long-term hydrological records gives a reasonable recharge value, in good agreement with GM(WB) and these methods can be paired to ensure the reliability of recharge value approximation in the same ranges. Applying various methods has given insight into methods selection to quantify recharge at LKRB and it is recommended that a lysimeter is installed as a direct method to estimate recharge.

Chelsea R. Hobby, Joshua L. Herndon, Colton A. Morrow et al.

Abstract Klebsiella pneumoniae represents a major threat to human health due to a combination of its nosocomial emergence and a propensity for acquiring antibiotic resistance. Dissemination of the bacteria from its native intestinal location creates severe, complicated infections that are particularly problematic in healthcare settings. Thus, there is an urgency for identifying novel treatment regimens as the incidence of highly antibiotic‐resistant bacteria rises. Recent findings have highlighted the ability of some Gram‐negative bacteria to utilize exogenous fatty acids in ways that modify membrane phospholipids and influence virulence phenotypes, such as biofilm formation and antibiotic resistance. This study explores the ability of K. pneumoniae to assimilate and respond to exogenous fatty acids. The combination of thin‐layer chromatography liquid chromatography‐mass spectrometry confirmed adoption of numerous exogenous polyunsaturated fatty acids (PUFAs) into the phospholipid species of K. pneumoniae. Membrane permeability was variably affected as determined by two dye uptake assays. Furthermore, the availability of many PUFAs lowered the MICs to the antimicrobial peptides polymyxin B and colistin. Biofilm formation was significantly affected depending upon the supplemented fatty acid.

article Editorial

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FABIO M. DALLA VECCHIA

Six stages (OS1-6) were identified by Kellner (2015) to establish the ontogeny of a given pterosaur fossil. These were used to support the erection of several new Triassic taxa including Bergamodactylus wildi, which is based on a single specimen (MPUM 6009) from the Norian of Lombardy, Italy. However, those ontogenetic stages are not valid because different pterosaur taxa had different tempos of skeletal development. Purported diagnostic characters of Bergamodactylus wildi are not autapomorphic or were incorrectly identified. Although minor differences do exist between MPUM 6009 and the holotype of Carniadactylus rosenfeldi, these do not warrant generic differentiation. Thus, MPUM 6009 is here retained within the taxon Carniadactylus rosenfeldi as proposed by Dalla Vecchia (2009a).

S. Hou, S. Hou, T. M. Jenk et al.

<p>An accurate chronology is the essential first step for a sound understanding of ice core records. However, dating ice cores drilled from the high-elevation glaciers is challenging and often problematic, leading to great uncertainties. The Guliya ice core, drilled to the bedrock (308.6&thinsp;m in length) along the western Kunlun Mountains on the north-western Tibetan Plateau (TP) and widely used as a benchmark for palaeoclimate research, is believed to reach  &gt; 500&thinsp;ka (thousand years) at its bottom. Meanwhile other Tibetan ice cores (i.e. Dasuopu and East Rongbuk in the Himalayas, Puruogangri in the central TP and Dunde in the north-eastern TP) are mostly of Holocene origin. In this study, we drilled four ice cores into bedrock (216.6, 208.6, 135.8 and 133.8&thinsp;m in length, respectively) from the Chongce ice cap  ∼ 30&thinsp;km to the Guliya ice core drilling site. We took measurements of ¹⁴C, ²¹⁰Pb, tritium and <i>β</i> activity for the ice cores, and used these values in a two-parameter flow model to establish the ice core depth–age relationship. We suggested that the Chongce ice cores might be of Holocene origin, consistent with the other Tibetan ice cores except Guliya. The remarkable discrepancy between the Guliya and all the other Tibetan ice core chronology implies that more effort is necessary to explore multiple dating techniques to confirm the age ranges of the TP glaciers, including those from Chongce and Guliya.</p>

T. Taskjelle, S. R. Hudson, M. A. Granskog et al.

Under-ice irradiance measurements were done on ponded first-year pack ice along three transects during the ICE12 expedition north of Svalbard. Bulk transmittances (400–900 nm) were found to be on average 0.15–0.20 under bare ice, and 0.39–0.46 under ponded ice. Radiative transfer modelling was done with a plane-parallel model. While simulated transmittances deviate significantly from measured transmittances close to the edge of ponds, spatially averaged bulk transmittances agree well. That is, transect-average bulk transmittances, calculated using typical simulated transmittances for ponded and bare ice weighted by the fractional coverage of the two surface types, are in good agreement with the measured values. Radiative heating rates calculated from model output indicates that about 20 % of the incident solar energy is absorbed in bare ice, and 50 % in ponded ice (35 % in pond itself, 15 % in the underlying ice). This large difference is due to the highly scattering surface scattering layer (SSL) increasing the albedo of the bare ice.

Andrey V. Maslov, Georg A. Petrov, Yury L. Ronkin

The features of the Sc, Cr, Co, Ni, Th and rare earth elements distribution in the black shales of the Riphean Murav’inskaya and Velsovskaya formations in southern part of the Lyapin-Kutim anticlinorium (Northern Ural) are analyzed. The contents of the listed elements in 20 samples of black shales are determined by the ICP-MS method at the IGG UB RAS (Ekaterinburg). Samples of the shales of the Murav’insky formation are selected from the outcrops along the river Vels, below the mouth of Pos’mak River, as well as along Pravaya Rassokha River. The selection was made from outcrops more or less evenly distributed over the studied area. The shales of the Velsovskaya formation were studied from the drilling holes in the basin of Sur’ya Vagranskaya River, as well as in outcrops along the Sibiryakovskaya Martayka and Pravaya Rassokha rivers. In the Sc-Th/Sc diagram, the data points of the black shales of the Murav’inskaya and Velsovskaya formations are fairly compact located between the points of the average composition of the Archean and Proterozoic granites, on the one hand, and tonalite-trondhjemite-granite (TTG) associations of the same age. Approximately the same distribution of the data points of the black shales of these formations can be seen in the La/Sc-Th/Co and La/Sm-Sc/Th diagrams. The average value of ΣРЗЭ in black shales of the Murav’inskaya formation is 316 ± 90 ppm, in the shales of the Velsovskaya Formation it is noticeably lower - 200 ± 47 ppm. The black shales of the Murav’inskaya Formation are substantially enriched with light lanthanides (La/Yb)Nmean = 40, and noticeably depleted by heavy lanthanides, (Gd/Yb)Nmean = 5.4. For the black shales of the Velsovsky formation (La/Yb)Nmean = 22, (Gd/Yb)Nmean = 3.1. This ones and a number of the other data make it possible to conclude that the complexes of rock-sources of fine aluminosiliciclastics for black shales of Murav’inskaya and Velsovskaya formations had a rather specific composition. On the basis of a comparison of the geochemical features of the black shales of the southern part of the Lyapin-Kutim anticlinorium and potential sources of fine aluminosiliciclastics, the conclusion is based that such rock complexes could be, from one side, the Archean and/or Proterozoic TTG associations and granites of the same age of the Eastern European platform, and, from another side, certain local rocks with high Cr contents and significant differentiation of REE, similar in composition to the products of kimberlite magmatism.

F. Shi, F. Shi, S. Zhao et al.

The dominant modes of variability of precipitation for the whole of China over the past millennium and the mechanism governing their spatial structure remain unclear. This is mainly due to insufficient high-resolution proxy records of precipitation in western China. Numerous tree-ring chronologies have recently been archived in publicly available databases through PAGES2k activities, and these provide an opportunity to refine precipitation field reconstructions for China. Based on 479 proxy records, including 371 tree-ring width chronologies, a tree-ring isotope chronology, and 107 drought/flood indices, we reconstruct the precipitation field for China for the past half millennium using the optimal information extraction method. A total of 3631 of 4189 grid points in the reconstruction field passed the cross-validation process, accounting for 86.68 % of the total number of grid points. The first leading mode of variability of the reconstruction shows coherent variations over most of China. The second mode is a north–south dipole in eastern China characterized by variations of the same sign in western China and northern China (except for Xinjiang province). It is likely controlled by the El Niño–Southern Oscillation (ENSO) variability. The third mode is a <q>sandwich</q> triple mode in eastern China including variations of the same sign in western China and central China. The last two modes are reproduced by most of the six coupled climate models' last millennium simulations performed in the framework of the Paleoclimate Modelling Intercomparison Project Phase III (PMIP3). In particular, the link of the second mode with ENSO is confirmed by the models. However, there is a mismatch between models and proxy reconstructions in the time development of different modes. This mismatch suggests the important role of internal variability in the reconstructed precipitation mode variations of the past 500 years.

V. M. Shapka, A. I. Lyashchuk, Yu. A. Andrushchenko et al.

The article is devoted to the issue of seismological monitoring and automatic warning of the personnel of potentially hazardous manufactures on the approaching of seismic threat and warning the population, in order to advance their preparation and minimize negative consequences. International experience of creating a system of early warning of earthquakes has been analyzed. The main factors, which determine the seismicity of the territory of Ukraine, have been considered. A model of the system of early earthquake warning for the objects of critical infrastructure of Ukraine has been proposed.

R. H. H. Janssen, A. Pozzer

We present a new submodel for the Modular Earth Submodel System (MESSy): the MiXed Layer (MXL) model for the diurnal dynamics of the convective boundary layer, including explicit representations of entrainment and surface fluxes. This submodel is embedded in a new MESSy base model (VERTICO), which represents a single atmospheric column. With the implementation of MXL in MESSy, MXL can be used in combination with other MESSy submodels that represent processes related to atmospheric chemistry. For instance, the coupling of MXL with more advanced modules for gas-phase chemistry (such as the Mainz Isoprene Mechanism 2 (MIM2)), emissions, dry deposition and organic aerosol formation than in previous versions of the MXL code is possible. Since MXL is now integrated in the MESSy framework, it can take advantage of future developments of this framework, such as the inclusion of new process submodels. <br><br> The coupling of MXL with submodels that represent other processes relevant to chemistry in the atmospheric boundary layer (ABL) yields a computationally inexpensive tool that is ideally suited for the analysis of field data, for evaluating new parametrizations for 3-D models, and for performing systematic sensitivity analyses. A case study for the DOMINO campaign in southern Spain is shown to demonstrate the use and performance of MXL/MESSy in reproducing and analysing field observations.

Rafael Albuquerque Xavier, Ana Luiza Coelho Neto

O mapeamento geomorfológico da bacia do rio Turvo confirmou as evidências apontadas em estudos anteriores, de que a bacia apresentava feições diferentes das observadas em bacias vizinhas. Foram observadas 222 depressões fechadas em divisores de drenagem, indicando forte atuação de mecanismos geoquímicos. Por outro lado, o reduzido número de voçorocas (33) e a presença de pacotes sedimentares poucos espessos (média de 7 metros), apontam a baixa efetividade dos processos mecânicos na bacia, sobretudo ao compararmos com a sub-bacia do rio Piracema, tributária do rio Bananal, com 117 voçorocas, terraços de até 23 metros de espessura e apenas 1 depressão fechada. Internamente, a bacia do rio Turvo apresentou variações, onde, de modo geral, a sub-bacia do rio das Pedras concentrou 21 das 33 voçorocas ativas, os mais espessos pacotes fluviais e apenas 16 depressões fechadas. Assim, conclui-se que a bacia do rio Turvo é fortemente influenciada pelos processos de denudação química, e a sub-bacia do rio das Pedras apresenta as maiores características da atuação do trabalho mecânico de toda a bacia.