Filtering by Subject: Geophysics and Seismology

The effect of uncertainties in creep activation energies on modeling ice flow and deformation

Meghana Ranganathan, Brent Minchew

Published: 2022-11-21
Subjects: Earth Sciences, Geophysics and Seismology, Glaciology, Physical Sciences and Mathematics

Ice deformation is commonly represented by a power-law constitutive relation, Glen's Flow Law, where deformation (strain) rate equals stress raised to the power n and multiplied by a flow-rate parameter A. Glen's Law represents bulk ice rheology as a single power-law even though multiple mechanisms, each with their own power-law relation and parametric values, act together during viscous [...]

Joint probabilistic inversion of 3D magnetotelluric and seismic data: Lithospheric structure and melting dynamics in southeast Australia

Maria Constanza Manassero, Sinan ozaydin, Juan Carlos Afonso, et al.

Published: 2022-11-18
Subjects: Geochemistry, Geophysics and Seismology, Volcanology

The thermochemical structure of the lithosphere exerts control on melting mechanisms in the mantle as well as the location of volcanic eruptions and ore deposits. Imaging the complex interactions between the lithosphere and asthenospheric mantle require the joint inversion of multiple data sets and their uncertainties. In particular, the combination of temperature and electrical conductivity with [...]

How reproducible is geophysical research? A review of the availability of code, software and data in journals

Mark Ireland, Guillermo Algarabel, Michael Steventon, et al.

Published: 2022-11-17
Subjects: Earth Sciences, Geophysics and Seismology, Oceanography and Atmospheric Sciences and Meteorology, Oil, Gas, and Energy, Other Earth Sciences, Physical Sciences and Mathematics, Sustainability

Geophysical research frequently makes use of agreed methodologies, formally published software, and bespoke code to process and analyse data. The reliability and repeatability of these methods is vital in maintaining the integrity of research findings and thereby avoiding the dissemination of unreliable results. In recent years there has been an increased attention on aspects of reproducibility, [...]

Evolution of intraplate magmatism atop a mantle plume: geochemical and chronological analysis of Shawahit Basalt, Harrat Rahat, Saudi Arabia

Gareth G Roberts, Patrick Ball

Published: 2022-11-15
Subjects: Earth Sciences, Geology, Geomorphology, Geophysics and Seismology, Stratigraphy, Tectonics and Structure, Volcanology

Harrat Rahat is the largest volcanic  eld in Saudi Arabia and has been active from ~10 Ma to the present day. Due to its close proximity to important population centres, Harrat Rahat's recent eruptions, the Medinah lava flows (< 1.7 Ma), have been extensively studied to identify volcanic risk. However, the evolution of Harrat Rahat's most extensive and oldest lava flows, known collectively as the [...]

Seismic Architecture of the Lithosphere-Asthenosphere System in the Western United States from a Joint Inversion of Body- and Surface-wave Observations: Distribution of Partial Melt in the Upper Mantle

Joseph Byrnes, James Gaherty, Emily Hopper

Published: 2022-11-08
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

Quantitative evaluation of the physical state of the upper mantle, including mapping temperature variations and the possible distribution of partial melt, requires accurately characterizing absolute seismic velocities near seismic discontinuities. We present a joint inversion for absolute but discontinuous models of shear-wave velocity (Vs) using 4 types of data: Rayleigh wave phases velocities, [...]

Tectonics is a hologram

Nicolas Coltice

Published: 2022-11-05
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

A hologram is an image in which each area contains almost all the information about the entire system. It is a metaphor commonly used for complex systems in which the whole is bigger than the sum of the parts because of self-organization. And also the whole is smaller than the sum of the parts, since the collective organization limits the behavior of dynamic features. The tectonic evolution of [...]

The Seismic Signature of California's Earthquakes, Droughts, and Floods

Marine Denolle, Tim Clements

Published: 2022-11-03
Subjects: Geophysics and Seismology

his study investigates changes in seismic velocities in the period 1999-2021 using about 700 permanent and temporary broadband seismic stations in the state of California. We compute single-station cross-correlations of the ambient seismic noise and use the coda-wave interferometry to measure the changes in seismic velocities ({\it dv/v}) using a stretching technique. We focus on the 2-4Hz [...]

Impact of Deccan Volcanism on Reorganization of the Indian plate kinematics

Amarjeet Ramesh Bhagat, S J Sangode, Ashish Dongre

Published: 2022-10-29
Subjects: Geology, Geophysics and Seismology, Tectonics and Structure

Western Indian Ocean basin shows one of the most complex signatures of the ocean floor anomalies by juxtaposition of the rapidly evolving, multiple spreading ridges, subduction systems and microcontinental slivers. This study based on ocean floor magnetic anomalies, gravity gradient map, tomographic profiles and geometrical kinematic models reports a significant westward drift of the Central [...]

Along-strike spatial variation in shallow slow earthquake activity in Hyuga-nada, southwest Japan

Satoru Baba, Shunsuke Takemura, Kazushige Obara, et al.

Published: 2022-10-28
Subjects: Geophysics and Seismology

Hyuga-nada, off the Pacific coast of Kyushu along the Nankai Trough in southwest Japan, is one of the most active slow earthquake regions around Japan. We estimated the energies of tremors and moments of very low frequency earthquakes (VLFEs) in Hyuga-nada using data from a permanent onshore broadband network and temporary ocean bottom seismometer observations. The energies and moments of these [...]

GANSim-surrogate: An integrated framework for conditional geomodelling and uncertainty analysis

Suihong Song, Dongxiao Zhang, Tapan Mukerji, et al.

Published: 2022-10-24
Subjects: Computational Engineering, Earth Sciences, Environmental Engineering, Fluid Dynamics, Geology, Geophysics and Seismology, Hydrology, Sedimentology

We propose a deep-learning framework (GANSim-surrogate) for conditioning subsurface geomodel realizations to static data and dynamic flow data. The static data includes well facies data, interpreted facies probability maps, and non-spatial global features, while dynamic data can include well data such as pressures and flow rates. The framework consists of a Convolutional Neural Network (CNN) [...]

Fault Friction Derived from Fault Bend Influence on Coseismic Slip During the 2019 Ridgecrest Mw 7.1 Mainshock

Chris Milliner, Saif Aati, Jean-Philippe Avouac

Published: 2022-10-18
Subjects: Earth Sciences, Geology, Geophysics and Seismology, Physical Sciences and Mathematics, Tectonics and Structure

The variation of stress on faults is important for our understanding of fault friction and the dynamics of earthquake ruptures. However, we still have little observational constraints on their absolute magnitude, or their variations in space and in time over the seismic cycle. Here we use a new geodetic imaging technique to measure the 3D coseismic slip vectors along the 2019 Ridgecrest surface [...]

Seismicity modulation due to hydrological loading in a stable continental region: a case study from the Jektvik swarm sequence in Northern Norway

Hasbi Ash Shiddiqi, Lars Ottemöller, Stéphane Rondenay, et al.

Published: 2022-10-10
Subjects: Geophysics and Seismology

Seismic swarms have been observed for more than 40 years along the coast of Nordland, Northern Norway. However, the detailed spatio-temporal evolution and mechanisms of these swarms have not yet been resolved due to the historically sparse seismic station coverage. An increased number of seismic stations now allows us to study a nearly decade-long swarm sequence in the Jektvik area during the [...]

Investigating the Eastern Alpine–Dinaric transition with teleseismic receiver functions: Evidence for subducted European Crust

Stefan Mroczek, Frederik Tilmann, Jan Pleuger, et al.

Published: 2022-10-09
Subjects: Geophysics and Seismology, Tectonics and Structure

Distributed Acoustic Sensing in a Greenlandic Outlet Glacier: Developing Machine Learning Approaches to Benefit Cryoseismic Data Analysis

Adam Booth, Poul Christoffersen, Andrew Pretorius, et al.

Published: 2022-10-08
Subjects: Geophysics and Seismology, Glaciology, Other Computer Sciences

The recognition of Distributed Acoustic Sensing (DAS) as a valuable tool for glaciological seismic applications is growing. However, besides the logistical challenges of installing fibre-optic cable, the volume of DAS data that can be collected in a field campaign poses computational challenges. In this paper, we show the potential of active-source DAS to image and characterise subglacial [...]

Bayesian inference on the initiation phase of the 2014 Iquique, Chile, earthquake

Cedric Twardzik, Zacharie Duputel, Romain Jolivet, et al.

Published: 2022-10-03
Subjects: Earth Sciences, Geophysics and Seismology, Physical Sciences and Mathematics

We investigate the initiation phase of the 2014 Mw8.1 Iquique earthquake in northern Chile. In particular, we focus on the month preceding the mainshock, a time period known to exhibit an intensification of the seismic and aseismic activity in the region. The goal is to estimate the time-evolution and partitioning of seismic and aseismic slip during the preparatory phase of the mainshock. To do [...]


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