Article
Geochemistry & Geophysics
Fabrizio Magrini, Lapo Boschi
Summary: This study evaluates the determination of surface-wave attenuation from ambient-noise data through numerical tests. The directionality of noise sources and the attenuation coefficient in the area of interest were identified from both experimental setups and real recordings. The method shows promise in accurately quantifying surface-wave attenuation at relatively high frequencies.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Luc Illien, Christoph Sens-Schoenfelder, Kuan-Yu Ke
Summary: Ground shaking induced by earthquakes can cause transient changes in seismic velocity, which are important for post-seismic hazard mitigation. However, these changes occur at small timescales and amplitudes that are challenging to link to laboratory experiments. This study investigates whether the estimation of relative seismic velocity changes can be improved using colocated stations according to the ergodic hypothesis.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Korbinian Sager, Victor C. Tsai, Yixiao Sheng, Florent Brenguier, Pierre Boue, Aurelien Mordret, Heiner Igel
Summary: The theory of Green's function retrieval requires homogeneously distributed noise sources, but low-frequency surface waves from ocean-crust interactions have been successfully used to image the crust with high spatial resolution. High-frequency body waves have sharper sensitivity to velocity contrasts and temporal changes at depth, with recent studies focusing on powerful, localized noise sources. Modeling correlations between P waves and analyzing their sensitivity to 3-D Earth structure is crucial for understanding and applying seismic interferometry in fault monitoring.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Multidisciplinary Sciences
Fabian Limberger, Georg Ruempker, Michael Lindenfeld, Hagen Deckert
Summary: In order to address the impact of ground vibrations caused by wind turbines on seismic observations, we have developed the first numerical model to predict the seismic wavefield generated by wind farms, taking into account factors such as wavefield interferences, surface topography, and attenuation.
SCIENTIFIC REPORTS
(2022)
Article
Environmental Sciences
Daniella Ayala-Garcia, Andrew Curtis, Michal Branicki
Summary: Cross-correlating seismic observations can estimate band-limited inter-receiver Green's functions, but issues arise from phase errors caused by correlated noise sources. Existing methods may not fully address this problem, but a new workflow has been developed to significantly mitigate these effects.
Article
Geosciences, Multidisciplinary
Tomoya Takano, Kiwamu Nishida
Summary: Microcracks in geomaterials lead to changes in elastic moduli under strain, resulting in seismic wave velocity variations that are crucial for understanding crustal dynamic processes. Previous research has not explored the characteristics of seismic velocity variations caused by large-scale tidal deformation. A new method utilizing a state-space model was developed to systematically evaluate tidal response to velocity variations. Large tide-induced seismic velocity changes were observed in the low S-wave velocity region of the shallow crust. Overall, the tidal responses of velocity variations provide new insights into the response mechanisms of the shallow crust to applied strain.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Y. Sheng
Summary: This study proposes a new processing technique called seismic stereometry to analyze seismic signals generated by cars, which considers the seismic source distribution and measures the seismic wave traveltime differences between sensors. The technique was demonstrated on a dense seismic array deployed on the southern San Andreas Fault segment, successfully inverting the shallow S-wave velocity using seismic waves generated by only one car. The developed technique, combined with distributed acoustic sensing technology, has great potential for applications in urban environments.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Environmental Sciences
Chunyu Liu, Hongfeng Yang, Baoshan Wang, Jun Yang
Summary: The study compares seasonal subsurface structural variations derived from airgun signals and ambient noise data, finding that airgun signals are influenced by reservoir water level fluctuations and are correlated with dominant frequency and travel time changes; ambient noise cross-correlation data shows seismic travel time changes corresponding to seasonal precipitation and evaporation effects.
Article
Geochemistry & Geophysics
Bruno Giammarinaro, Christina Tsarsitalidou, Gregor Hillers, Julien de Rosny, Leonard Seydoux, Stefan Catheline, Michel Campillo, Philippe Roux
Summary: Numerical experiments are conducted to explore subsurface imaging at subwavelength distances for dense seismic arrays in a laterally homogeneous layered medium. A time-reversal approach is used to simulate fundamental mode Rayleigh surface wavefields, and it is found that synthesized spatial autocorrelation fields support focal spot imaging. The accuracy of phase velocity and dispersion estimates obtained from focal spot properties is assessed through systematic tests involving different wave components and incidence conditions. The results indicate that dense array seismic Rayleigh wave focal spot imaging can increase depth sensitivity and support subwavelength resolution of lateral medium variations.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
N. L. Bennington, S. J. Ohlendorf, C. H. Thurber, M. M. Haney
Summary: This study uses ambient noise interferometry to investigate temporal changes in seismic velocity at Okmok volcano in Alaska during the inter-eruptive period between two eruptions. The depth-constrained changes in seismic velocity distinguish volcanic and non-volcanic processes, and theoretical volumetric strain modeling of volcanic deformation is also conducted. The joint analysis technique developed in this study allows for the determination of volcanic deformation location, with potential implications for monitoring active magma storage at sparsely instrumented volcanoes worldwide.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Michal Chamarczuk, Michal Malinowski, Deyan Draganov, Emilia Koivisto, Suvi Heinonen, Sanna Rotsa
Summary: This study applies full-scale 3D seismic virtual-source survey (VSS) for near-mine mineral exploration, using ambient noise data for analysis and imaging. The results demonstrate the capability of VSS in providing high-quality geological images in areas with terrain restrictions.
Article
Geosciences, Multidisciplinary
Tianze Liu, Peter M. Shearer
Summary: Seismic noise, including both surface waves and body waves, has been widely used for imaging Earth's structure. This study focuses on identifying and analyzing body-wave noise, specifically PKP waves, using array analyses. The results suggest that the phase differential between PKS and PKP can potentially be used for shear-wave-splitting analysis. Additionally, the study highlights the heterogeneous nature of sources for body-wave noise in both space and time, which should be taken into account in future studies.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Victor C. Tsai, Korbinian Sager
Summary: This study demonstrates the use of Bayesian inference approach in calculating the expected cross correlation of seismic signals, leading to a better understanding of its relationship with the Green's function. The Bayesian derivation replicates the equipartition result, and with stronger constraints, deviation from the expected Green's function is observed, allowing for more reliable comparison with observations.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Daniel Wells, Fan-Chi Lin, Kristine Pankow, Ben Baker, John Bartley
Summary: South-central Utah is characterized by volcanic and geothermal activity, as well as high surface heat flux. This study used seismic tomography to investigate the subsurface shear velocity structure in the region. The results showed a correlation between low velocity anomalies and high heat flux and geothermal activity, indicating a possible common heat source from the mantle.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
J. Mueller, M. van Laaten, T. Eulenfeld, U. Wegler
Summary: The M-w 7.8 earthquake in Turkey on 6 February 2023 was unique because of its shallow depth, long fault plane, and extensive network of seismic instruments. The earthquake resulted in significant casualties and material losses in both Turkey and Syria. However, the abundance of seismic observations and aftershocks provides an opportunity to enhance our understanding of earthquake processes.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Engineering, Civil
Caroline Le Bouteiller, Guillaume Chambon, Florence Naaim-Bouvet, Nicolle Mathys
Summary: The experimental study focused on natural hyperconcentrated flows of fine sediment from the Draix-Bleone observatory. The research showed a transition from turbulent Newtonian flows to laminar non-Newtonian flows as concentration increased. Yield stress was found to appear for volumetric concentrations higher than 26-29%, and a unique trend was observed in the relationship between Reynolds number and friction coefficient for all flume experiments, allowing identification of different flow regimes.
JOURNAL OF HYDRAULIC RESEARCH
(2021)
Article
Engineering, Geological
Sylvain Fiolleau, Denis Jongmans, Gregory Bievre, Guillaume Chambon, Pascal Lacroix, Agnes Helmstetter, Marc Wathelet, Michel Demierre
Summary: The study reveals that the Harmaliere landslide exhibits two types of behaviors - upper sliding and lower flowing, with a total mass transfer of over 6 x 10(6) m(3) during multiple reactivations, and a mass transfer of 1 x 10(6) m(3) during the 2016 reactivation.
Article
Mechanics
Olivier Ozenda, Pierre Saramito, Guillaume Chambon
Summary: A two-velocity fluid model is proposed to describe particle migration in mono-disperse suspensions, allowing explicit boundary conditions on particle velocity and strict enforcement of mass conservation and jamming limit.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2022)
Article
Geochemistry & Geophysics
Yara Maalouf, Gregory Bievre, Christophe Voisin, Naji Khoury
Summary: Earth dams are globally important for water management, but internal erosion caused by water seepage is a major concern. This study conducted a controlled laboratory experiment to detect and monitor water seepage using various techniques. The findings suggest that seismic monitoring methods can effectively describe the complex process of internal erosion and potentially differentiate different phases.
NEAR SURFACE GEOPHYSICS
(2022)
Article
Chemistry, Analytical
Stijn Wielandt, Sebastian Uhlemann, Sylvain Fiolleau, Baptiste Dafflon
Summary: Landslides are a global and frequent natural hazard, and current instruments for slope stability monitoring often have limitations such as high cost, complex installation, and low resolution. This research introduces a novel sensing approach using low-cost accelerometer arrays for monitoring soil deformation, providing depth-resolved measurements that can inform about shallow sliding surfaces. Wireless sensor networks comprising these sensors are shown to be crucial for landslide early warning systems.
Article
Geography, Physical
Sylvain Fiolleau, Denis Jongmans, Gregory Bievre, Guillaume Chambon, Olivier Michel, Laurent Borgniet
Summary: Flow-like landslides in clay slopes pose major threats to people and infrastructure, but the mechanisms leading to solid-fluid transition in clay are poorly understood. This study uses unmanned aerial vehicle (UAV) acquisitions to quantify the degradation of clay at the surface of a landslide. The study shows that the applied methodology is appropriate to analyze the material degradation pattern and reveals the degradation rate and differences in different areas.
EARTH SURFACE PROCESSES AND LANDFORMS
(2022)
Article
Geography, Physical
Sylvain Fiolleau, Sebastian Uhlemann, Nicola Falco, Baptiste Dafflon
Summary: This study proposes a novel framework to estimate the probability of failure in highly developed urban areas by combining remote sensing and geophysical data. The results show that slope angle, soil thickness, and cohesion are the most important parameters. Seismic noise measurements were performed to estimate soil thickness, and supervised classification of remote sensing data was used to map vegetation type and related root cohesion. The developed approach can be applied to other study sites and is particularly important in areas of active vegetation management.
Article
Automation & Control Systems
Mohit Mishra, Gildas Besancon, Guillaume Chambon, Laurent Baillet
Summary: This paper presents an optimal estimation method for state and parameter in a special class of ODE-PDE system based on Lagrangian multiplier and adjoint state method. The effectiveness of this method is validated through two application examples of different landslide models.
INTERNATIONAL JOURNAL OF CONTROL
(2022)
Article
Geography, Physical
Antoine Bernard, Pascal Hagenmuller, Maurine Montagnat, Guillaume Chambon
Summary: Snow settles due to metamorphism and deformation of the ice matrix under gravity. The compression tests and monitoring of snow microstructure showed that deformation mainly reduces the pore space and increases the coordination number, while metamorphism mainly affects the grain and bond sizes.
JOURNAL OF GLACIOLOGY
(2023)
Article
Computer Science, Information Systems
Stijn Wielandt, Sebastian Uhlemann, Sylvain Fiolleau, Baptiste Dafflon
Summary: Densely distributed sensor networks can greatly improve environmental observations by providing real-time data with high spatiotemporal resolution. This study presents a framework for wirelessly connected distributed sensor arrays for monitoring temperature and/or deformation near the surface. The researchers focused on implementing a novel time division duplex version of the LoRa protocol to enable battery powered base stations and enhance network efficiency. They also proposed a delta encoding algorithm to minimize transmissions and improve battery life. The results demonstrate the feasibility of these methods for low-power environmental wireless sensor networks.
JOURNAL OF SIGNAL PROCESSING SYSTEMS FOR SIGNAL IMAGE AND VIDEO TECHNOLOGY
(2023)
Article
Geosciences, Multidisciplinary
S. Uhlemann, I. Shirley, S. Wielandt, C. Ulrich, C. Wang, S. Fiolleau, J. Peterson, J. Lamb, E. Thaler, J. Rowland, S. S. Hubbard, B. Dafflon
Summary: Assessing the extent of permafrost is crucial for understanding the impact of climate change on Arctic ecosystems. This study proposes a new method that combines temperature and electrical resistivity measurements to estimate the distribution of permafrost. The results show that certain vegetation and slope characteristics are associated with warmer and smaller permafrost bodies, as well as a higher occurrence of taliks.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Sylvain Fiolleau, Sebastian Uhlemann, Stijn Wielandt, Baptiste Dafflon
Summary: A novel approach combining passive seismic and low-cost inclinometer monitoring methods is presented in this study to improve understanding of landslide activation mechanisms and their controls. The results show the value of combining these two methods for observing and monitoring landslide hazards. The combination of passive seismic monitoring and low-cost inclinometers enables quantification of sliding mechanisms and the design of landslide early warning systems.
JOURNAL OF APPLIED GEOPHYSICS
(2023)
Article
Mechanics
Danila Denisenko, Gael Loic Richard, Guillaume Chambon
Summary: This study presents a model for the flow of Bingham fluids down an inclined plane using an asymptotic method in the shallow-flow approximation. The model incorporates a specific regularization technique to avoid the divergence of the strain rate and introduces a true yield stress to characterize the material behavior. The model is derived by averaging the mass, momentum, and energy balance equations over the depth, resulting in three hyperbolic equations for the fluid depth, average velocity, and enstrophy. The model features new relaxation source terms and exhibits stabilizing effects of plasticity.
JOURNAL OF NON-NEWTONIAN FLUID MECHANICS
(2023)
Article
Geography, Physical
Baptiste Dafflon, Stijn Wielandt, John Lamb, Patrick McClure, Ian Shirley, Sebastian Uhlemann, Chen Wang, Sylvain Fiolleau, Carlotta Brunetti, Franklin H. Akins, John Fitzpatrick, Samuel Pullman, Robert Busey, Craig Ulrich, John Peterson, Susan S. Hubbard
Summary: This study presents the development and validation of a novel distributed temperature profiling (DTP) system for measuring soil and snow temperature. The system provides high-resolution temperature measurements with low cost and power consumption, enabling advances in understanding various cryospheric and hydro-biogeochemical processes.
