arXiv - PHYS - Geophysics最新文献_第2页

Bridging the Rossby number gap in rapidly rotating thermal convection 缩小快速旋转热对流中的罗斯比数差距

arXiv - PHYS - Geophysics Pub Date : 2024-09-13 DOI: arxiv-2409.08536

Adrian van Kan, Keith Julien, Benjamin Miquel, Edgar Knobloch

{"title":"Bridging the Rossby number gap in rapidly rotating thermal convection","authors":"Adrian van Kan, Keith Julien, Benjamin Miquel, Edgar Knobloch","doi":"arxiv-2409.08536","DOIUrl":"https://doi.org/arxiv-2409.08536","url":null,"abstract":"Geophysical and astrophysical fluid flows are typically buoyantly driven and\u0000are strongly constrained by planetary rotation at large scales. Rapidly\u0000rotating Rayleigh-B'enard convection (RRRBC) provides a paradigm for direct\u0000numerical simulations (DNS) and laboratory studies of such flows, but the\u0000accessible parameter space remains restricted to moderately fast rotation\u0000(Ekman numbers $rm Ek gtrsim 10^{-8}$), while realistic $rm Ek$ for\u0000astro-/geophysical applications are significantly smaller. Reduced equations of\u0000motion, the non-hydrostatic quasi-geostrophic equations describing the\u0000leading-order behavior in the limit of rapid rotation ($rm Ek to 0$) cannot\u0000capture finite rotation effects, leaving the physically most relevant part of\u0000parameter space with small but finite $rm Ek$ currently inaccessible. Here, we\u0000introduce the rescaled incompressible Navier-Stokes equations (RiNSE), a\u0000reformulation of the Navier-Stokes-Boussinesq equations informed by the\u0000scalings valid for $rm Ekto 0$. We provide the first full DNS of RRRBC at\u0000unprecedented rotation strengths down to $rm Ek=10^{-15}$ and below and show\u0000that the RiNSE converge to the asymptotically reduced equations.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142252788","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

A convolutional neural network approach to deblending seismic data 卷积神经网络去叠加地震数据的方法

arXiv - PHYS - Geophysics Pub Date : 2024-09-12 DOI: arxiv-2409.07930

Jing Sun, Sigmund Slang, Thomas Elboth, Thomas Larsen Greiner, Steven McDonald, Leiv-J Gelius

{"title":"A convolutional neural network approach to deblending seismic data","authors":"Jing Sun, Sigmund Slang, Thomas Elboth, Thomas Larsen Greiner, Steven McDonald, Leiv-J Gelius","doi":"arxiv-2409.07930","DOIUrl":"https://doi.org/arxiv-2409.07930","url":null,"abstract":"For economic and efficiency reasons, blended acquisition of seismic data is\u0000becoming more and more commonplace. Seismic deblending methods are always\u0000computationally demanding and normally consist of multiple processing steps.\u0000Besides, the parameter setting is not always trivial. Machine learning-based\u0000processing has the potential to significantly reduce processing time and to\u0000change the way seismic deblending is carried out. We present a data-driven deep\u0000learning-based method for fast and efficient seismic deblending. The blended\u0000data are sorted from the common source to the common channel domain to\u0000transform the character of the blending noise from coherent events to\u0000incoherent distributions. A convolutional neural network (CNN) is designed\u0000according to the special character of seismic data, and performs deblending\u0000with comparable results to those obtained with conventional industry deblending\u0000algorithms. To ensure authenticity, the blending was done numerically and only\u0000field seismic data were employed, including more than 20000 training examples.\u0000After training and validation of the network, seismic deblending can be\u0000performed in near real time. Experiments also show that the initial signal to\u0000noise ratio (SNR) is the major factor controlling the quality of the final\u0000deblended result. The network is also demonstrated to be robust and adaptive by\u0000using the trained model to firstly deblend a new data set from a different\u0000geological area with a slightly different delay time setting, and secondly\u0000deblend shots with blending noise in the top part of the data.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211762","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

Short-range order stabilizes a cubic Fe alloy in Earth's inner core 短程秩序稳定了地球内核中的立方铁合金

arXiv - PHYS - Geophysics Pub Date : 2024-09-12 DOI: arxiv-2409.08008

Zhi Li, Sandro Scandolo

引用次数: 0

MgO Miscibility in Liquid Iron 氧化镁在液态铁中的混溶性

arXiv - PHYS - Geophysics Pub Date : 2024-09-12 DOI: arxiv-2409.07681

Leslie Insixiengmay, Lars Stixrude

引用次数: 0

DNN-based workflow for attenuating seismic interference noise and its application to marine towed streamer data from the Northern Viking Graben 基于 DNN 的地震干扰噪音衰减工作流程及其在北维京海湾海洋拖曳流媒体数据中的应用

arXiv - PHYS - Geophysics Pub Date : 2024-09-12 DOI: arxiv-2409.07890

Jing Sun, Song Hou, Alaa Triki

{"title":"DNN-based workflow for attenuating seismic interference noise and its application to marine towed streamer data from the Northern Viking Graben","authors":"Jing Sun, Song Hou, Alaa Triki","doi":"arxiv-2409.07890","DOIUrl":"https://doi.org/arxiv-2409.07890","url":null,"abstract":"To separate seismic interference (SI) noise while ensuring high signal\u0000fidelity, we propose a deep neural network (DNN)-based workflow applied to\u0000common shot gathers (CSGs). In our design, a small subset of the entire\u0000to-be-processed data set is first processed by a conventional algorithm to\u0000obtain an estimate of the SI noise (from now on called the SI noise model). By\u0000manually blending the SI noise model with SI-free CSGs and a set of simulated\u0000random noise, we obtain training inputs for the DNN. The SI-free CSGs can be\u0000either real SI-free CSGs from the survey or SI-attenuated CSGs produced in\u0000parallel with the SI noise model from the conventional algorithm depending on\u0000the specific project. To enhance the DNN's output signal fidelity, adjacent\u0000shots on both sides of the to-be-processed shot are used as additional channels\u0000of the input. We train the DNN to output the SI noise into one channel and the\u0000SI-free shot along with the intact random noise into another. Once trained, the\u0000DNN can be applied to the entire data set contaminated by the same types of SI\u0000in the training process, producing results efficiently. For demonstration, we\u0000applied the proposed DNN-based workflow to 3D seismic field data acquired from\u0000the Northern Viking Graben (NVG) of the North Sea, and compared it with a\u0000conventional algorithm. The studied area has a challenging SI contamination\u0000problem with no sail lines free from SI noise during the acquisition. The\u0000comparison shows that the proposed DNN-based workflow outperformed the\u0000conventional algorithm in processing quality with less noise residual and\u0000better signal preservation. This validates its feasibility and value for real\u0000processing projects.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"63 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211763","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 early Solar System and its meteoritical witnesses 早期太阳系及其流星见证者

arXiv - PHYS - Geophysics Pub Date : 2024-09-11 DOI: arxiv-2409.07212

Emmanuel Jacquet, Cornelis Dullemond, Joanna Drążkowska, Steven Desch

引用次数: 0

Ice viscosity governs hydraulic fracture that causes rapid drainage of supraglacial lakes 冰的粘度决定了导致超冰川湖泊快速排水的水力裂缝

arXiv - PHYS - Geophysics Pub Date : 2024-09-09 DOI: arxiv-2409.05478

Tim Hageman, Jessica Mejía, Ravindra Duddu, Emilio Martínez-Pañeda

{"title":"Ice viscosity governs hydraulic fracture that causes rapid drainage of supraglacial lakes","authors":"Tim Hageman, Jessica Mejía, Ravindra Duddu, Emilio Martínez-Pañeda","doi":"arxiv-2409.05478","DOIUrl":"https://doi.org/arxiv-2409.05478","url":null,"abstract":"Full thickness crevasses can transport water from the glacier surface to the\u0000bedrock where high water pressures can open kilometre-long cracks along the\u0000basal interface, which can accelerate glacier flow. We present a first\u0000computational modelling study that describes time-dependent fracture\u0000propagation in an idealised glacier causing rapid supraglacial lake drainage. A\u0000novel two-scale numerical method is developed to capture the elastic and\u0000viscoelastic deformations of ice along with crevasse propagation. The\u0000fluid-conserving thermo-hydro-mechanical model incorporates turbulent fluid\u0000flow and accounts for melting/refreezing in fractures. Applying this model to\u0000observational data from a 2008 rapid lake drainage event indicates that viscous\u0000deformation exerts a much stronger control on hydrofracture propagation\u0000compared to thermal effects. This finding contradicts the conventional\u0000assumption that elastic deformation is adequate to describe fracture\u0000propagation in glaciers over short timescales (minutes to several hours) and\u0000instead demonstrates that viscous deformation must be considered to reproduce\u0000observations of lake drainage rate and local ice surface elevation change. As\u0000supraglacial lakes continue expanding inland and as Greenland Ice Sheet\u0000temperatures become warmer than -8 degree C, our results suggest rapid lake\u0000drainages are likely to occur without refreezing, which has implications for\u0000the rate of sea level rise.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211796","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

Robust Estimation of Structural Orientation Parameters and 2D/3D Local Anisotropic Tikhonov Regularization 结构方向参数的鲁棒估计和二维/三维局部各向异性提霍诺夫正则化

arXiv - PHYS - Geophysics Pub Date : 2024-09-09 DOI: arxiv-2409.05754

Ali Gholami, Silvia Gazzola

{"title":"Robust Estimation of Structural Orientation Parameters and 2D/3D Local Anisotropic Tikhonov Regularization","authors":"Ali Gholami, Silvia Gazzola","doi":"arxiv-2409.05754","DOIUrl":"https://doi.org/arxiv-2409.05754","url":null,"abstract":"Understanding the orientation of geological structures is crucial for\u0000analyzing the complexity of the Earths' subsurface. For instance, information\u0000about geological structure orientation can be incorporated into local\u0000anisotropic regularization methods as a valuable tool to stabilize the solution\u0000of inverse problems and produce geologically plausible solutions. We introduce\u0000a new variational method that employs the alternating direction method of\u0000multipliers within an alternating minimization scheme to jointly estimate\u0000orientation and model parameters in both 2D and 3D inverse problems.\u0000Specifically, the proposed approach adaptively integrates recovered information\u0000about structural orientation, enhancing the effectiveness of anisotropic\u0000Tikhonov regularization in recovering geophysical parameters. The paper also\u0000discusses the automatic tuning of algorithmic parameters to maximize the new\u0000method's performance. The proposed algorithm is tested across diverse 2D and 3D\u0000examples, including structure-oriented denoising and trace interpolation. The\u0000results show that the algorithm is robust in solving the considered large and\u0000challenging problems, alongside efficiently estimating the associated tilt\u0000field in 2D cases and the dip, strike, and tilt fields in 3D cases. Synthetic\u0000and field examples show that the proposed anisotropic regularization method\u0000produces a model with enhanced resolution and provides a more accurate\u0000representation of the true structures.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211786","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

Reduced-order modeling for complex 3D seismic wave propagation 复杂三维地震波传播的降阶建模

arXiv - PHYS - Geophysics Pub Date : 2024-09-09 DOI: arxiv-2409.06102

John M. Rekoske, Dave A. May, Alice-Agnes Gabriel

{"title":"Reduced-order modeling for complex 3D seismic wave propagation","authors":"John M. Rekoske, Dave A. May, Alice-Agnes Gabriel","doi":"arxiv-2409.06102","DOIUrl":"https://doi.org/arxiv-2409.06102","url":null,"abstract":"Elastodynamic Green's functions are an essential ingredient in seismology as\u0000they form the connection between direct observations of seismic waves and the\u0000earthquake source. They are also fundamental to various seismological\u0000techniques including physics-based ground motion prediction and kinematic or\u0000dynamic source inversions. In regions with established 3D models of the Earth's\u0000elastic structure, 3D Green's functions can be computed using numerical\u0000simulations of seismic wave propagation. However, such simulations are\u0000computationally expensive which poses challenges for real-time ground motion\u0000prediction. Here, we use a reduced-order model (ROM) approach that enables the\u0000rapid evaluation of approximate Green's functions. The ROM technique developed\u0000approximates three-component surface velocity wavefields obtained from\u0000numerical simulations of seismic wave propagation. We apply our ROM approach to\u0000a 50 km x 40 km area in the greater Los Angeles area accounting for topography,\u0000site effects, 3D subsurface velocity structure, and viscoelastic attenuation.\u0000The ROM constructed for this region enables rapid computation (0.001 CPU hours)\u0000of complete, high-resolution, 0.5 Hz surface velocity wavefields that are\u0000accurate for a shortest wavelength of 1.0 km. Using leave-one-out cross\u0000validation, we measure the accuracy of our Green's functions in both the\u0000time-domain and frequency-domain. Averaged across all sources and receivers,\u0000the error in the rapid seismograms is less than 0.01 cm/s. We demonstrate that\u0000the ROM can accurately and rapidly reproduce simulated seismograms for\u0000generalized moment tensor sources in our region, as well as kinematic sources\u0000by using a finite fault model of the 1987 Mw 5.9 Whittier Narrows earthquake as\u0000an example. We envision that our rapid, approximate Green's functions will be\u0000useful for constructing rapid ground motion synthetics with high spatial\u0000resolution.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"410 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211766","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

Thermal and magnetic evolution of an Earth-like planet with a basal magma ocean 具有基底岩浆海洋的类地行星的热演化和磁演化

arXiv - PHYS - Geophysics Pub Date : 2024-09-09 DOI: arxiv-2409.06031

Victor Lherm, Miki Nakajima, Eric G. Blackman

{"title":"Thermal and magnetic evolution of an Earth-like planet with a basal magma ocean","authors":"Victor Lherm, Miki Nakajima, Eric G. Blackman","doi":"arxiv-2409.06031","DOIUrl":"https://doi.org/arxiv-2409.06031","url":null,"abstract":"Earth's geodynamo has operated for over 3.5 billion years. The magnetic field\u0000is currently powered by thermocompositional convection in the outer core, which\u0000involves the release of light elements and latent heat as the inner core\u0000solidifies. However, since the inner core nucleated no more than 1.5 billion\u0000years ago, the early dynamo could not rely on these buoyancy sources. Given\u0000recent estimates of the thermal conductivity of the outer core, an alternative\u0000mechanism may be required to sustain the geodynamo prior to nucleation of the\u0000inner core. One possibility is a silicate dynamo operating in a long-lived\u0000basal magma ocean. Here, we investigate the structural, thermal, buoyancy, and\u0000magnetic evolution of an Earth-like terrestrial planet. Using modern equations\u0000of state and melting curves, we include a time-dependent parameterization of\u0000the compositional evolution of an iron-rich basal magma ocean. We combine an\u0000internal structure integration of the planet with energy budgets in a coupled\u0000core, basal magma ocean, and mantle system. We determine the\u0000thermocompositional convective stability of the core and the basal magma ocean,\u0000and assess their respective dynamo activity using entropy budgets and magnetic\u0000Reynolds numbers. Our conservative nominal model predicts a transient basal\u0000magma ocean dynamo followed by a core dynamo after 1 billion years. The model\u0000is sensitive to several parameters, including the initial temperature of the\u0000core-mantle boundary, the parameterization of mantle convection, the\u0000composition of the basal magma ocean, the radiogenic content of the planet, as\u0000well as convective velocity and magnetic scaling laws. We use the nominal model\u0000to constrain the range of basal magma ocean electrical conductivity and core\u0000thermal conductivity that sustain a dynamo.","PeriodicalId":501270,"journal":{"name":"arXiv - PHYS - Geophysics","volume":"80 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142211785","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