Article
Engineering, Marine
Marie-Noel R. Matthews, Darren S. Ireland, David G. Zeddies, Robert H. Brune, Cynthia D. Pyc
Summary: Concerns about environmental impacts of air gun surveys drive research on marine vibroseis systems which produce lower acoustic pressure but longer duration signals compared to air guns. Studies show more behavioral disturbance for marine mammals with MV arrays than air gun arrays.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
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
Multidisciplinary Sciences
Lise Retailleau, Lucia Gualtieri
Summary: This study investigates the seismic signals generated by typhoons during their extra-tropical transition, comparing observed sources with theoretical sources from a numerical ocean wave model and assessing the impact of ocean resonance and coastal reflection. The location and lateral extent of the seismic source are shown to be period- and phase-dependent, providing crucial information for ambient noise imaging and complementing satellite data. The authors locate the maximum seismic energy imprint and lateral extent of seismic sources, presenting a new tool to understand the generation mechanism of secondary microseisms body waves.
NATURE COMMUNICATIONS
(2021)
Article
Geochemistry & Geophysics
Yizhi Wang, Ting Yang, Yuechu Wu, Dan Liu, Xinfeng Huang, Jun Wang, Weixing Zhong, Haitao Shou, Yong Zhou, Yongshun Chen
Summary: This study analyzes the ambient noise features in the South China Sea using seismic data collected by newly developed ocean bottom seismographs. The results reveal unique noise characteristics, including distinct spectra for double frequency microseisms and weak spectra for single frequency microseisms. The study also identifies a long-period Earth's hum signal in the vertical component at periods greater than 50 s.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Sirawich Pipatprathanporn, Frederik J. Simons
Summary: A fleet of autonomously drifting profiling floats known as mermaid monitors seismic activity using hydrophones inside oceans. The floats recorded signals from 213 global earthquakes, with only 10 automatically reported. After removing seismic and other signals, infrasonic ambient noise recorded at 1500 m depth was analyzed, showing interactions of oceanic surface gravity waves.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
L. A. Ermert, K. Sager, T. Nissen-Meyer, A. Fichtner
Summary: The method developed in the study effectively constrained the global source distribution of the Earth's hum, with dominant sources in the Southern Hemisphere during winter and exceptions in the Izu-Bonin-Mariana arc. Strong hum sources were found to be associated with coastlines or bathymetric highs. The practical feasibility of frequency-dependent noise source inversion was demonstrated, potentially improving full-waveform ambient noise inversions and enhancing our understanding of noise generation physics.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Wenbo Wu, Zhichao Shen, Shirui Peng, Zhongwen Zhan, Jorn Callies
Summary: Limited observational coverage makes monitoring the global ocean warming a challenging problem. Seismic ocean thermometry (SOT) complements existing point measurements by inferring large-scale ocean temperature changes using sound waves generated by submarine earthquakes. The application of SOT on CTBTO hydrophones in the East Indian Ocean exhibits higher signal-to-noise ratio and improved temporal resolution.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Wenbo Wu, Zhichao Shen, Shirui Peng, Zhongwen Zhan, Joern Callies
Summary: Limited observational coverage makes monitoring global ocean warming, especially in the deep ocean, challenging. Seismic ocean thermometry (SOT) uses sound waves generated by submarine earthquakes to infer large-scale ocean temperature changes. This study demonstrates that hydrophones from the Comprehensive Nuclear-Test-Ban Treaty Organization can record T waves with higher signal-to-noise ratio compared to land-based T-wave stations, improving the temporal resolution of SOT.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Yann Capdeville
Summary: This work introduces a new method to replace Dirac point sources in seismic wave equations with a smooth source term using the non-periodic two-scale homogenization method, leading to accurate results in both far-source and near-source wavefields. The method has potential significance in solving forward and inverse seismic problems.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Linjia Li, Huailiang Li, Xianguo Tuo, Zhen Yang, Wenzheng Rong
Summary: In this study, a time-domain polarization estimation method based on the instantaneous frequency of the seismic signals is proposed. An optimal time window is constructed to estimate the polarization parameters. Compared with the conventional time window, the polarization properties estimated using the optimal time window can achieve more accurate seismic phase identification and effectively denoise noisy seismic recordings while increasing the signal-to-noise ratio and preserving signal information.
SEISMOLOGICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
C. J. Ebinger, Miriam C. Reiss, Ian Bastow, Mary M. Karanja
Summary: The East African rift system is formed above mantle upwellings and the formation of rifts is related to lithospheric thinning and magmatic activity. The amount of splitting varies spatially and the fast axes are predominantly parallel to the orientation of the rifts. Thick lithospheric modules have less splitting and different orientations, which may indicate mantle plume flow. Splitting rotates and increases in strength as it enters the rift zones, suggesting that the anisotropy is mainly present at shallow depths.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geosciences, Multidisciplinary
Han Xiao, Toshiro Tanimoto, Zack J. Spica, Beatriz Gaite, Sandra Ruiz-Barajas, Mohan Pan, Loic Viens
Summary: This study used DAS data to analyze the sources of high-frequency microseisms, finding that they are located within 7 to 27 km from the shore and move quickly along narrow areas. This new method provides a new approach for understanding the complex seismic phenomena happening in the oceans.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Jeremy Boger-Lombard, Yevgeny Slobodkin, Ori Katz
Summary: Non-line-of-sight (NLoS) imaging is a challenging task in various fields, such as autonomous vehicles, smart cities, and defense applications. Recent studies have focused on using active SONAR/LiDAR techniques to measure time-of-flight information and map the Green functions for hidden targets. In this study, we explore the possibility of localizing acoustic NLoS targets without controlled active sources by leveraging passive correlations-based imaging techniques. Our results show successful localization and tracking of a hidden human subject using correlations of uncontrolled noise sources recorded by multiple detectors, suggesting that passive detectors can replace controlled active sources for NLoS localization when there is a sufficiently wideband noise present in the scene.
SCIENTIFIC REPORTS
(2023)
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
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
Sebastian Carrasco, Brigitte Knapmeyer-Endrun, Ludovic Margerin, Cedric Schmelzbach, Keisuke Onodera, Lu Pan, Philippe Lognonne, Sabrina Menina, Domenico Giardini, Eleonore Stutzmann, John Clinton, Simon Stahler, Martin Schimmel, Matthew Golombek, Manuel Hobiger, Miroslav Hallo, Sharon Kedar, William Bruce Banerdt
Summary: The study investigates the local subsurface structure at the InSight landing site on Mars using the horizontal-to-vertical (H/V) spectral ratio inversion technique. Different H/V curves were obtained from ambient vibrations and seismic events. The recordings during high-wind periods were less favorable for traditional analysis, while the S-wave coda of marsquakes provided better results. The derived H/V curve showed a trough at 2.4 Hz and a peak at 8 Hz.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Fisheries
M. F. Cronin, S. Swart, C. A. Marandino, C. Anderson, P. Browne, S. Chen, W. R. Joubert, U. Schuster, R. Venkatesan, C. Addey, O. Alves, F. Ardhuin, S. Battle, M. A. Bourassa, Z. Chen, M. Chory, C. Clayson, R. B. de Souza, M. du Plessis, M. Edmondson, J. B. Edson, S. T. Gille, J. Hermes, V Hormann, S. A. Josey, M. Kurz, T. Lee, F. Maicu, E. H. Moustahfid, S-A Nicholson, E. S. Nyadjro, J. Palter, R. G. Patterson, S. G. Penny, L. P. Pezzi, N. Pinardi, J. E. J. Reeves Eyre, N. Rome, A. C. Subramanian, C. Stienbarger, T. Steinhoff, A. J. Sutton, H. Tomita, S. M. Wills, C. Wilson, L. Yu
Summary: The Observing Air-Sea Interactions Strategy (OASIS) is a program that aims to improve Earth system forecasts, CO2 uptake assessments, and provide ocean information for decision makers. It focuses on creating a global network of mobile air-sea observing platforms, a satellite network optimized for measuring air-sea fluxes, and improving the representation of air-sea coupling in Earth system models. The program consists of various activities such as network design, model improvement, partnership building, and best practices experiments.
ICES JOURNAL OF MARINE SCIENCE
(2023)
Article
Astronomy & Astrophysics
Jiaqi Li, Caroline Beghein, Paul Davis, Mark. A. Wieczorek, Scott M. M. McLennan, Doyeon Kim, Ved Lekic, Matthew Golombek, Martin Schimmel, Eleonore Stutzmann, Philippe Lognonne, William Bruce Banerdt
Summary: The shallowest layer beneath the Mars InSight Lander site has low seismic wave velocity due to high porosity and other lithological factors. The SsPp phase was detected on Mars for the first time, confirming the existence of an 8 km interface and a large wave speed contrast across it. The average P-wave speed in the top crustal layer was found to be between 2.5 and 3.2 km/s, providing a more precise estimate than previous studies.
EARTH AND SPACE SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Antoine Hochet, Guillaume Dodet, Florian Sevellec, Marie-Noelle Bouin, Anindita Patra, Fabrice Ardhuin
Summary: Satellite observations over the past 30 years indicate that changes in wave height are primarily driven by internal variability and not yet significantly affected by anthropogenic climate change. The dominant influence of climate change on wave height trends is expected to emerge after 2050.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Zongbo Xu, Adrien Broquet, Nobuaki Fuji, Taichi Kawamura, Philippe Lognonne, Jean-Paul Montagner, Lu Pan, Martin Schimmel, Eleonore Stutzmann, William Bruce Banerdt
Summary: Understanding the Martian crust and uppermost mantle is crucial for studying the planet's evolution, and NASA's InSight mission has provided seismic data to reveal the interior structure. While most studies have focused on the crustal structure beneath the InSight lander, the seismic structure of other regions remains poorly known. This study investigates the crustal structure along the Medusa Fossae Formation and the dichotomy using surface-wave data, and the findings suggest the presence of a high-velocity layer and a common intra-crustal structure in this region.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
P. Lognonne, M. Schimmel, E. Stutzmann, P. Davis, M. Drilleau, G. Sainton, T. Kawamura, M. P. Panning, W. B. Banerdt
Summary: We have detected normal modes on Mars for the first time using vertical records from InSight's broad-band seismometer after a marsquake occurred on sol 1222. Our catalog includes 60 potential eigenfrequencies between 3 and 12 mHz, detected using the phasor walkout approach due to their low signal-to-noise ratio. The amplitudes of the normal modes are consistent with the upper limit of the S1222a magnitude and show high quality factors. Additionally, we have observed the first Martian hum before the quake at several frequencies. These proposed frequencies are within 1-sigma of those predicted by published models based on body wave travel time inversions. This detection of normal modes is significant as it is the first on a terrestrial planet other than Earth and can contribute to future interior models incorporating normal modes frequencies, surface waves velocities, and body wave travel times.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Oceanography
Matias Alday, Fabrice Ardhuin
Summary: Numerical wave models can reproduce wave evolution in all directions and wavelengths, though the understanding and representation of physical processes affecting wave energy distribution is limited. Models are typically adjusted to reproduce dominant wave characteristics, such as significant wave height, mean direction, and dominant wavelengths. Recent updates in wave dissipation parameterizations have shown realistic energy levels and directional distribution for shorter waves. This new formulation of wave energy sink can reproduce the variability of measured infrasound power and is sensitive to factors such as non-linear energy transfer and the influence of dominant and relatively long waves on the dissipation of shorter waves in other directions.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Geosciences, Multidisciplinary
G. A. Jones, A. M. G. Ferreira, B. Kulessa, M. Schimmel, A. Berbellini, A. Morelli
Summary: Rayleigh wave ellipticity measurements from seismic ambient noise recorded on the Greenland Ice Sheet (GrIS) show complex and anomalous behavior at wave periods sensitive to ice (T < 3-4 s). To understand these complex observations, we compare them with synthetic ellipticity measurements obtained from synthetic ambient noise computed for various seismic velocity and attenuation models, including surface wave overtone effects. We find that in dry snow conditions within the interior of the GrIS, to first order the anomalous ellipticity observations can be explained by ice models associated with the accumulation and densification of snow into firn. We also show that the distribution of ellipticity measurements is strongly sensitive to seismic attenuation and the thermal structure of the ice. Our results suggest that Rayleigh wave ellipticity is well suited for monitoring changes in firn properties and thermal composition of the Greenland and Antarctic ice sheets in a changing climate.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Sebastian Carrasco, Brigitte Knapmeyer-Endrun, Ludovic Margerin, Zongbo Xu, Rakshit Joshi, Martin Schimmel, Eleonore Stutzmann, Constantinos Charalambous, Philippe Lognonne, W. Bruce Banerdt
Summary: We measured the ellipticity of direct Rayleigh waves at intermediate periods (15-35 s) on Mars using recordings of three large seismic Martian events, including the largest event recorded by the InSight mission. These measurements, along with other seismic data, were used to determine the local crustal structure at the InSight landing site. The results suggest the presence of crustal discontinuities at depths around 10 km, 20 km, and a strong discontinuity at approximately 37 km, interpreted as the crust-mantle interface, as well as a shallow low-velocity layer of 2-3 km thickness.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Oceanography
Marine De Carlo, Fabrice Ardhuin, Annabelle Ollivier, Adrien Nigou
Summary: Recent satellite altimeter retracking and filtering methods have reduced noise in estimates of wave height, allowing for the study of processes with smaller scales. The contribution of wave groups to the uncertainty in wave height measurements is quantified using directional wave spectra measured by the China-France Ocean Satellite (CFOSAT). This study demonstrates that wave group effects account for a significant portion of the variance in wave height measurements, with the largest impact observed during storms and in the presence of long swells.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Geochemistry & Geophysics
Sergi Ventosa, Martin Schimmel
Summary: Seismic ambient noise has nonstationary time-frequency statistics, requiring better interstation correlation methods. The wavelet phase cross-correlation (WPCC) functions, incorporating ideas from the phase cross-correlation (PCC) method and wavelet cross-correlation, are introduced to analyze seismic ambient noise and extract clean broadband signals. WPCC has shown benefits in improving baseline corrections, signal extraction, and measurement accuracy compared to PCC. The use of GPU offsets the increase in computational cost, making WPCC an efficient approach for processing large data volumes in seismic interferometry studies.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
Article
Geochemistry & Geophysics
Jordi Diaz, Sergi Ventosa, Martin Schimmel, Mario Ruiz, Albert Macau, Anna Gabas, David Marti, Ozgenc Akin, Jaume Verges
Summary: In this study, ambient seismic noise acquired in the Cerdanya Basin was used to evaluate the capability of different methodologies to map the geometry of a small-scale sedimentary basin. The results from various techniques, including autocorrelations, ambient noise Rayleigh wave tomography, HVSR, and band-pass-filtered ambient noise amplitude mapping, consistently showed that the deeper part of the basin is located in its central part, reaching depths of 600-700 m close to the Tet fault trace. The overall consistency between the results provides solid constraints to the basement depth estimation and helps improve the geological characterization of the Cerdanya Basin.
Article
Geosciences, Multidisciplinary
Sebastian Carrasco, Brigitte Knapmeyer-Endrun, Ludovic Margerin, Zongbo Xu, Rakshit Joshi, Martin Schimmel, Eleonore Stutzmann, Constantinos Charalambous, Philippe Lognonne, W. Bruce Banerdt
Summary: In this study, we measured the ellipticity of direct Rayleigh waves at intermediate periods on Mars for the first time. These measurements, along with other seismic data, were used to infer the local crustal structure at the InSight landing site. Our results suggest the presence of intra-crustal discontinuities and a strong crust-mantle interface at around 37 km depth. We also found a shallow low-velocity layer of 2-3 km thickness. The lower seismic wave velocities in the crust compared to nearby regions indicate a higher porosity or alteration of the local crust.
GEOPHYSICAL RESEARCH LETTERS
(2023)