arXiv: Geophysics最新文献

Improving discrete element simulations of sea ice break up: Applications to Nares Strait 改进的离散元海冰破裂模拟:在纳尔斯海峡的应用

arXiv: Geophysics Pub Date : 2021-05-11 DOI: 10.1002/ESSOAR.10507028.1

B. West, D. O'Connor, M. Parno, Max Krackow, C. Polashenski

引用次数: 2

Seismic-ionospheric perturbations in ionospheric TEC and plasma parameters associated with the 14 July 2019 Mw7.2 Laiwui earthquake detected by the GPS and CSES GPS和CSES探测到的2019年7月14日莱威Mw7.2地震电离层TEC和等离子体参数的地震-电离层扰动

arXiv: Geophysics Pub Date : 2021-02-06 DOI: 10.21203/RS.3.RS-223597/V1

Yuanzheng Wen, Guangxue Wang, D. Tao, Jiayi Zong, Z. Zeren, X. Shen

{"title":"Seismic-ionospheric perturbations in ionospheric TEC and plasma parameters associated with the 14 July 2019 Mw7.2 Laiwui earthquake detected by the GPS and CSES","authors":"Yuanzheng Wen, Guangxue Wang, D. Tao, Jiayi Zong, Z. Zeren, X. Shen","doi":"10.21203/RS.3.RS-223597/V1","DOIUrl":"https://doi.org/10.21203/RS.3.RS-223597/V1","url":null,"abstract":"\u0000 In this study, with cross-valid analysis of total electron content (TEC) data of the global ionospheric map (GIM) from GPS and plasma parameters data recorded by China Seismo-Electromagnetic Satellite (CSES), signatures of seismic-ionospheric perturbations related to the 14 July 2019 Mw 7.2 Laiwui earthquake were detected. After distinguishing the solar and geomagnetic activities, three positive temporal anomalies were found around the epicenter 1 day, 3 days and 8 days before the earthquake (14 July 2019) along with a negative anomaly 6 days after the earthquake, which also agrees well with the TEC spatial variations in latitude-longitude-time (LLT) maps. To further confirm the anomalies, the ionospheric plasma parameters (electron, O+ and He+ densities) recorded by the Langmuir probe (LAP) and Plasma Analyzer Package (PAP) onboard CSES were analyzed by using the moving mean method (MMM), which also presented remarkable enhancements along the orbits around the epicenter on day 2, day 4 and day 7 before the earthquake. To make the investigations more convincing, the disturbed orbits were compared with their corresponding four nearest revisiting orbits, whose results indeed indicate the existence of plasma parameters anomalies associated with the Laiwui earthquake. All these results illustrated that the GPS and CSES observed unusual ionospheric perturbations are highly associated with the Mw 7.2 Laiwui earthquake, which also strongly indicates the existence of pre-seismic ionospheric anomalies over the earthquake region.","PeriodicalId":390991,"journal":{"name":"arXiv: Geophysics","volume":"153 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2021-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132312511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Effect of Declustering on the Size Distribution of Mainshocks 聚类对主震大小分布的影响

arXiv: Geophysics Pub Date : 2020-12-16 DOI: 10.1785/0220200231

Leila Mizrahi, Shyam Nandan, S. Wiemer

{"title":"The Effect of Declustering on the Size Distribution of Mainshocks","authors":"Leila Mizrahi, Shyam Nandan, S. Wiemer","doi":"10.1785/0220200231","DOIUrl":"https://doi.org/10.1785/0220200231","url":null,"abstract":"Declustering aims to divide earthquake catalogs into independent events (mainshocks), and dependent (clustered) events, and is an integral component of many seismicity studies, including seismic hazard assessment. We assess the effect of declustering on the frequency-magnitude distribution of mainshocks. In particular, we examine the dependence of the b-value of declustered catalogs on the choice of declustering approach and algorithm-specific parameters. Using the catalog of earthquakes in California since 1980, we show that the b-value decreases by up to 30% due to declustering with respect to the undeclustered catalog. The extent of the reduction is highly dependent on the declustering method and parameters applied. We then reproduce a similar effect by declustering synthetic earthquake catalogs with known b-value, which have been generated using an Epidemic-Type Aftershock Sequence (ETAS) model. Our analysis suggests that the observed decrease in b-value must, at least partially, arise from the application of the declustering algorithm on the catalog, rather than from differences in the nature of mainshocks versus fore- or aftershocks. We conclude that declustering should be considered as a potential source of bias in seismicity and hazard studies.","PeriodicalId":390991,"journal":{"name":"arXiv: Geophysics","volume":"129 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124232859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 29

Potential and scientific requirements of optical clock networks for validating satellite gravity missions 验证卫星重力任务的光时钟网络的潜力和科学要求

arXiv: Geophysics Pub Date : 2020-12-04 DOI: 10.5194/EGUSPHERE-EGU21-10912

S. Schröder, S. Stellmer, J. Kusche

{"title":"Potential and scientific requirements of optical clock networks for validating satellite gravity missions","authors":"S. Schröder, S. Stellmer, J. Kusche","doi":"10.5194/EGUSPHERE-EGU21-10912","DOIUrl":"https://doi.org/10.5194/EGUSPHERE-EGU21-10912","url":null,"abstract":"The GRACE and GRACE-FO missions have provided an unprecedented quantification of large-scale changes in the water cycle. However, it is still an open problem of how these missions' data sets can be referenced to a ground truth. Meanwhile, stationary optical clocks show fractional instabilities below $10^{-18}$ when averaged over an hour, and continue to be improved in terms of precision and accuracy, uptime, and transportability. The frequency of a clock is affected by the gravitational redshift, and thus depends on the local geopotential; a relative frequency change of $10^{-18}$ corresponds to a geoid height change of about $1$ cm. Here we suggest that this effect could be further exploited for sensing large-scale temporal geopotential changes via a network of clocks distributed at the Earth's surface. In fact, several projects have already proposed to create an ensemble of optical clocks connected across Europe via optical fibre links. Our hypothesis is that a clock network with collocated GNSS receivers spread over Europe - for which the physical infrastructure is already partly in place - would enable us to determine temporal variations of the Earth's gravity field at time scales of days and beyond, and thus provide a new means for validating satellite missions such as GRACE-FO or a future gravity mission. Here, we show through simulations how ice, hydrology and atmosphere variations over Europe could be observed with clock comparisons in a future network that follows current design concepts in the metrology community. We assume different scenarios for clock and GNSS uncertainties and find that even under conservative assumptions - a clock error of $10^{-18}$ and vertical height control error of $1.4$ mm for daily measurements - hydrological signals at the annual time scale and atmospheric signals down to the weekly time scale could be observed.","PeriodicalId":390991,"journal":{"name":"arXiv: Geophysics","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116286780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Multiscale modeling of the effective viscoplastic behavior of Mg 2 SiO 4 wadsleyite: bridging atomic and polycrystal scales m2sio4wadsleite有效粘塑性行为的多尺度建模:桥接原子和多晶尺度

arXiv: Geophysics Pub Date : 2020-11-24 DOI: 10.5802/CRMECA.61

O. Castelnau, K. Derrien, S. Ritterbex, P. Carrez, P. Cordier, H. Moulinec

{"title":"Multiscale modeling of the effective viscoplastic behavior of Mg 2 SiO 4 wadsleyite: bridging atomic and polycrystal scales","authors":"O. Castelnau, K. Derrien, S. Ritterbex, P. Carrez, P. Cordier, H. Moulinec","doi":"10.5802/CRMECA.61","DOIUrl":"https://doi.org/10.5802/CRMECA.61","url":null,"abstract":"The viscoplastic behavior of polycrystalline Mg$_2$SiO$_4$ wadsleyite aggregates, a major high pressure phase of the mantle transition zone of the Earth (depth range: 410 -- 520 km), is obtained by properly bridging several scale transition models. At the very fine nanometric scale corresponding to the disloca-tion core structure, the behavior of thermally activated plastic slip is modeled for strain-rates relevant for laboratory experimental conditions, at high pressure and for a wide range of temperatures, based on the Peierls-Nabarro-Galerkin model. Corresponding single slip reference resolved shear stresses and associated constitutive equations are deduced from Orowan's equation in order to describe the average viscoplastic behavior at the grain scale, for the easiest slip systems. These data have been implemented in two grain-polycrystal scale transition models, a mean-field one (the recent Fully-Optimized Second-Order Viscoplastic Self-Consistent scheme of [44]) allowing rapid evaluation of the effective viscosity of polycrystalline aggregates , and a full-field (FFT based [45] [33]) method allowing investigating stress and strain-rate localization in typical microstructures and heterogeneous activation of slip systems within grains. Calculations have been performed at pressure and temperatures relevant for in-situ conditions. Results are in very good agreement with available mechanical tests conducted at strain-rates typical for laboratory experiments.","PeriodicalId":390991,"journal":{"name":"arXiv: Geophysics","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134643714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 4

Effect of Initial Volume on the Run-Out Behavior of Submerged Granular Columns 初始体积对浸没颗粒柱跳动行为的影响

arXiv: Geophysics Pub Date : 2020-11-05 DOI: 10.1061/9780784483435.025

Qiuyu Wang, R. Hosseini, K. Kumar

{"title":"Effect of Initial Volume on the Run-Out Behavior of Submerged Granular Columns","authors":"Qiuyu Wang, R. Hosseini, K. Kumar","doi":"10.1061/9780784483435.025","DOIUrl":"https://doi.org/10.1061/9780784483435.025","url":null,"abstract":"Submarine landslides transport thousands of cubic meters of sediment across continental shelves even at slopes as low as 1{deg} and can cause significant casualty and damage to infrastructure. The run-out mechanism in a submarine landslide is affected by factors such as the initial packing density, permeability, slope angle, and initial volume. While past studies have focused on the influence of density, permeability, and slope angle on the granular column collapse, the impact of volume on the run-out characteristics has not been investigated. This study aims to understand how the initial volume affects the run-out using a two-dimensional coupled lattice Boltzman and discrete element (LBM-DEM) method. The coupled LBM-DEM approach allows simulating fluid flow at the pore-scale resolution to understand the grain-scale mechanisms driving the complex continuum-scale response in the granular column collapse. For submerged granular column collapse, the run-out mechanism is heavily influenced by the interaction between the grains and the surrounding fluid. The development of negative pore pressures during shearing and hydrodynamic drag forces inhibit the flow. On the other hand, entrainment of water resulting in hydroplaning enhances the flow. With an increase in volume, the interaction between the grains and the surrounding fluid varies, causing changes in the run-out behavior. For smaller volumes, the forces inhibiting the underwater flow predominates, resulting in shorter run-outs than their dry counterparts. At large volumes, hydroplaning results in larger run-out than the dry cases, despite the inhibiting effects of drag forces and negative pore pressures.","PeriodicalId":390991,"journal":{"name":"arXiv: Geophysics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124935185","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Earthquake and Electrochemistry: Unraveling the Unpredictable 地震和电化学:揭开不可预测的面纱

arXiv: Geophysics Pub Date : 2020-11-02 DOI: 10.21203/rs.3.rs-106129/v1

A. Das

{"title":"Earthquake and Electrochemistry: Unraveling the Unpredictable","authors":"A. Das","doi":"10.21203/rs.3.rs-106129/v1","DOIUrl":"https://doi.org/10.21203/rs.3.rs-106129/v1","url":null,"abstract":"Earthquakes are measured using well defined seismic parameters such as seismic moment (Mo), moment magnitude (Mw), and released elastic energy(E). How this tremendous amount of energy is accumulated silently deep inside the earth's crust? The most obvious question in seismic research remains unanswered. We found an inherent and intriguing connection between the released energy in an earthquake and electrochemical potential induced in an ultra-thin metal oxide electrode immersed in an aqueous pH solution, which leads us to understand the origin of the energy accumulation process in an earthquake. A huge electrochemical potential is accumulated from numerous electrochemical cells formed in a unique layer structure of hydrated clay minerals (predominantly smectite), which resulted in a lightning-like discharge in the lithosphere (hypocenter). The subsequent thunder-like massive shockwave is produced, which initiates tectonic plate movement along a fault line, probably through acoustic fluidization (AF), and resulting seismic energy is transmitted as primary wave (P-wave), secondary wave (S-wave), and surface waves. The presence of electrical voltage in the hypocenter directly supports the seismic electric signal (SES), further strengthening the VAN method of earthquake prediction. Our finding is supported by a plethora of research and observation devoted to seismic science. This study will indeed find its significance if immediate action is implemented to monitor the evolution of electrochemical potential, seismic electrical signal (SES), and ionic activity in the fault zone at lithosphere as well as in the ionosphere for predicting an impending earthquake for saving human lives as early as possible.","PeriodicalId":390991,"journal":{"name":"arXiv: Geophysics","volume":"146 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115701505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Stability Assessment of a Tailings Storage Facility Using a Non-local Constitutive Model Accounting for Anisotropic Strain-Softening 基于各向异性应变软化非局部本构模型的尾矿库稳定性评价

arXiv: Geophysics Pub Date : 2020-10-07 DOI: 10.1007/978-3-030-64518-2_40

M. Sottile, N. Labanda, A. Kerguelen, I. A. Cueto, A. Sfriso

引用次数: 2

A Family of Constitutive Models Implemented in PLAXIS to Simulate Cemented Mine Backfill. 基于PLAXIS的矿山胶结充填体模拟本构模型族。

arXiv: Geophysics Pub Date : 2020-10-07 DOI: 10.3233/STAL190087

M. Sottile, N. Labanda, I. Mendive, O. Ledesma, A. Sfriso

引用次数: 0

A risk assessment of downdrag induced by reconsolidation of clays after upwards pipe jacking 顶管后黏土再固结引起的下阻力风险评价

arXiv: Geophysics Pub Date : 2020-09-14 DOI: 10.1201/9780429321559-39

N. Labanda, A. Sfriso, D. Tsingas, R. Aradas, M. Martini

{"title":"A risk assessment of downdrag induced by reconsolidation of clays after upwards pipe jacking","authors":"N. Labanda, A. Sfriso, D. Tsingas, R. Aradas, M. Martini","doi":"10.1201/9780429321559-39","DOIUrl":"https://doi.org/10.1201/9780429321559-39","url":null,"abstract":"Salini-Impregilo is building part of the largest sanitary sewer system in the history of Argentina in the suburbs of Buenos Aires City, to serve a population of almost five million people. The project is an outfall TBM tunnel 12 km long, starting from a reception shaft in the river margin, and transporting the sewage 35 meters below the textit{Rio de la Plata} riverbed to the point of discharge. Within the final kilometer of the tunnel, a set of 36 standing pipes so-called textit{risers} are constructed by driving steel tubes upwards and passing through dense sands, sandy clays and soft clays. Risers are linked-up with the launching lining segment using flange unions. \u0000Driving of risers upwards will generate excess pore pressure and disturbance in fine soils and, once the pipe is placed in its final position, negative skin friction due to reconsolidation and creep. A risk assessment of the downdrag is presented in this paper, based on the estimation of the force and/or displacement in the riser-tunnel union generated by this effect. The issues of whether it is desirable to instalock the riser-tunnel union at an early age after installation of the riser and the time lapse required to reduce negative skin friction effects are discussed. Results are validated by comparing the model results with field measurements in prototype models.","PeriodicalId":390991,"journal":{"name":"arXiv: Geophysics","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128861594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0