Article
Geochemistry & Geophysics
Yingjie Xia, Xuping Feng, Xiaofei Chen
Summary: This study provides a theoretical explanation for the burst of energy near zero time observed in the cross-correlation function (CCF) of seismic noise recorded at two stations. The phenomenon is attributed to the constructive interference of body waves radiating from sources near the mid-vertical plane between the receivers. The distribution of noise sources and the correlation of surface waves do not contribute to this interference.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Stefan Mroczek, Frederik Tilmann
Summary: In the field of seismic interferometry, cross-correlations are used to extract Green's function from ambient noise data. By applying a single station variation of the method, using autocorrelations, zero-offset reflections can be retrieved in a stratified Earth. However, the results targeting Moho signals with ambient noise autocorrelations can be ambiguous and require additional analysis with receiver functions to confirm the findings. The combination of autocorrelations and receiver functions allows for independent estimates of crustal parameters such as P and S velocities, as well as Moho depth.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Alberto Refice, Guido Pasquariello, Fabio Bovenga
Summary: This article introduces a viable parameter, fuzzy entropy (F-E), as a measure to characterize MTI time series. F-E can be used as a discriminative parameter to isolate meaningful MTI time series without the need for a predefined model. The calculation of F-E has low computational cost and can be easily performed as a prescreening filter.
IEEE GEOSCIENCE AND REMOTE SENSING LETTERS
(2022)
Article
Environmental Sciences
Fabio Bovenga, Guido Pasquariello, Alberto Refice
Summary: This study introduces a method for automatically identifying relevant changes in MTInSAR displacement time series, and proposes a procedure for automatically recognizing the minimum number of parameters needed for reliable modeling of a given time series. Through the use of polynomial models, it is possible to effectively approximate the piecewise linear trends used to model warning signals preceding the failure of structures. Finally, the proposed procedure is demonstrated on displacement time series derived from processing Sentinel-1 data.
Article
Geochemistry & Geophysics
Ruth A. Beckel, Christopher Juhlin
Summary: Passive reflection seismic interferometry (PRSI) faces challenges in imaging the subsurface structure due to the difficulty in meeting the illumination requirements, which can introduce artefacts in the results. The study found that dipping reflectors have a significant impact on the results, with contributions mainly from the hangingwall and weak and kinematically incorrect contributions from the footwall. The type and position of artefacts depend on source azimuth and modelling type, and it is crucial to distinguish between meaningful reflections and artefacts during interpretation.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Youngseok Song, Soon Jee Seol, Joongmoo Byun, Koichi Hayashi, Shunjia Tan
Summary: The imaging of subsurface structures is crucial in subsurface engineering projects, providing valuable information about active faults and layer boundaries. The body wave imaging method using urban traffic noise has gained attention for its low cost and continuous measurement capabilities in urban areas. This study systematically analyzed traffic noise sources using field data from the Xiadian fault in Hebei province, China. By modifying the data processing workflow, spurious events were suppressed and reflections were imaged more clearly in the final stacked image. The fault spatial locations and layer boundary depth variation obtained were consistent with previous studies.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Physics, Multidisciplinary
Jungmin Kim, Dayeong Lee, Sunkyu Yu, Namkyoo Park
Summary: Photonic systems can utilize time as an alternative to space, eliminating the need for spatial patterning. Recent studies have shown the importance of temporal degree of freedom in photonics and its analogy with spatial axes. In this research, we investigate the design of photonic time disorder to achieve optical functionalities without spatial patterning.
Article
Mechanics
K. A. Shishmarev, T. I. Khabakhpasheva, A. A. Korobkin
Summary: This study investigates the unsteady two-dimensional problem of a thin liquid layer with prescribed time-dependent influx. The ratio of the liquid thickness variation to the influx velocity serves as a small parameter. The study recovers the flow structure near a singularity caused by unbounded growth of the liquid layer thickness using asymptotic analysis. The inner free-surface flow is shown to be two-dimensional, potential, non-linear, and independent of the original problem's parameters.
Article
Engineering, Electrical & Electronic
Yuta Izumi, Othmar Frey, Simone Baffelli, Irena Hajnsek, Motoyuki Sato
Summary: This paper presents a practical and efficient method for atmospheric phase screen mitigation based on the coherent pixels technique (CPT) displacement velocity estimation algorithm, suitable for terrestrial radar interferometry (TRI) applications. Through the introduction of a continuous operational mode processing framework and validation and algorithm comparison studies on TRI data from a Swiss mountainous region, the efficiency of the proposed approach was demonstrated.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2021)
Article
Computer Science, Artificial Intelligence
Lasitha S. Vidyaratne, Mahbubul Alam, Alexander M. Glandon, Anna Shabalina, Chris Tennant, Khan M. Iftekharuddin
Summary: The study introduces a novel deep cellular recurrent neural network (DCRNN) architecture to efficiently process complex multidimensional time-series data with spatial information. The cellular recurrent architecture enables location-aware synchronous processing of time-series data while ensuring efficiency in dealing with high-dimensional inputs.
IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS
(2022)
Article
Geochemistry & Geophysics
Clara Gomez-Garcia, Sergei Lebedev, Thomas Meier, Yihe Xu, Florian Le Pape, Lars Wiesenberg
Summary: Ambient noise autocorrelations can be used to reconstruct seismic reflection response without active sources or earthquakes. Previous studies have located and mapped discontinuities at different crustal depths using this technique. A method design is required to determine a reliable reflection response, and in this study, a workflow is designed to obtain the P-wave reflectivity with a focus on the Moho depth.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
M. Rezaeifar, F. Lavoue, G. Maggio, Y. Xu, C. J. Bean, L. Pinzon-Rincon, S. Lebedev, F. Brenguier
Summary: Train-induced vibrations can be utilized as a powerful source for high-resolution subsurface imaging through seismic interferometry, as demonstrated in this study using three days of railroad traffic data recorded by a seismograph array in Dublin, Ireland. The results from our interferometry approaches show significant surface and body wave energy, consistent with nearby borehole data and an active seismic profile. These findings confirm the value of train-generated vibrations as a signal source for high-resolution subsurface imaging, while also highlighting the need for consideration of train geometry and the cross-correlation approach in body wave interferometry studies.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Environmental Sciences
Evandro Balbi, Martino Terrone, Francesco Faccini, Davide Scafidi, Simone Barani, Silvano Tosi, Laura Crispini, Paola Cianfarra, Flavio Poggi, Gabriele Ferretti
Summary: In this study, PS interferometry was applied to investigate a landslide in Santo Stefano d'Aveto, Italy. Cross-correlation analysis was used to divide the landslide into different sectors with specific types of movement, possibly influenced by the geomorphological setting and regional tectonics of the area.
Article
Geography, Physical
Matthias Schlogl, Barbara Widhalm, Michael Avian
Summary: The study presents a methodological framework for structural deformation monitoring of critical infrastructure assets using differential SAR interferometry, which derives daily rates for vertical and horizontal deformation components through post-processing analysis, showcasing its applicability in continuous monitoring of key infrastructure assets.
ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING
(2021)
Article
Environmental Sciences
Yoon Taek Jung, Sang-Eun Park, Hyun-Cheol Kim
Summary: The objective of this study is to extend the InSAR analysis of seasonal ground deformations to boreal forest regions, where monitoring ground deformation is particularly important in terms of better understanding active layer dynamics under various ecological and geological conditions. This study presented a strategy to analyze the time series SAR data in the freezing season to estimate the differential phase for seasonal ground deformation while overcoming the problem of coherence losses due to the rapid growth of vegetation during the short growing season. The results for the Yakutian lowlands illustrated the potential of SAR remote sensing to observe and quantify spatial details of the thermal and hydrological properties inside the active layer soil even in highly vegetated subarctic boreal forest areas.
REMOTE SENSING OF ENVIRONMENT
(2023)
Article
Engineering, Geological
Rafal Czarny, Zenon Pilecki, Nori Nakata, Elzbieta Pilecka, Krzysztof Krawiec, Paulina Harba, Maciej Barnas
ENGINEERING GEOLOGY
(2019)
Article
Geochemistry & Geophysics
Jing Jian, Roel Snieder, Nori Nakata
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2020)
Article
Geochemistry & Geophysics
Rie Nakata, David Lumley, Gary Hampson, Kurt Nihei, Nori Nakata
Article
Geochemistry & Geophysics
Fangyu Li, Tong Bai, Nori Nakata, Bin Lyu, Wenzhan Song
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2020)
Editorial Material
Geochemistry & Geophysics
Malcolm C. A. White, Hongjian Fang, Nori Nakata, Yehuda Ben-Zion
SEISMOLOGICAL RESEARCH LETTERS
(2020)
Article
Geochemistry & Geophysics
Bin Lyu, Non Nakata
GEOPHYSICAL JOURNAL INTERNATIONAL
(2020)
Article
Geochemistry & Geophysics
Tong Bai, Bin Lyu, Paul Williamson, Nori Nakata
Summary: Geometric-mean reverse time migration (GmRTM) is a powerful imaging method that generates high-resolution source images and is robust to noise. We proposed two grouping strategies and evaluated their performance using synthetic and field data, demonstrating the advantages of each strategy in different scenarios.
Article
Geography, Physical
Julien Chaput, Rick Aster, Marianne Karplus, Nori Nakata
Summary: Researchers collected high-frequency seismic data on the Antarctic ice sheet and identified three Rayleigh wave modes with systematic spatial particle motion characteristics at frequencies up to 50 Hz. These observations are consistent with shallow lateral structural variations in Antarctic firn.
JOURNAL OF GLACIOLOGY
(2022)
Article
Environmental Sciences
Hilary Chang, Nori Nakata
Summary: Distributed acoustic sensing (DAS) has great potential for monitoring natural-resource reservoirs and borehole conditions. This study demonstrates that seismic interferometry based on deconvolution is a convenient tool for analyzing the complicated wavefield in DAS data. However, good coupling is still required to extract the signal of interest. The study also explores the applications of this technique in monitoring borehole conditions and changes in reservoir properties.
Article
Geochemistry & Geophysics
Colin N. Pennington, Hilary Chang, Justin L. Rubinstein, Rachel E. Abercrombie, Nori Nakata, Takahiko Uchide, Elizabeth S. Cochran
Summary: This study investigates the sensitivity of slip inversions to station distribution and choice of EGF. By using a dense distribution of geophones, accurate slip inversions are achieved, allowing for the exploration of the sensitivity of slip inversions. Results show that station distributions with uniform coverage of azimuth and distance can retrieve the overall pattern of slip, but the estimated amplitude of slip can vary. The choice of EGF can also shift the location and amplitude of resolved slip areas.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2022)
Article
Geochemistry & Geophysics
Tong Bai, Bin Lyu, Fangyu Li, Paul Williamson, Nori Nakata
Summary: Passive source location is a crucial problem in earthquake seismology and reservoir characterization. In this study, we propose an extended GmRTM imaging method that can be applied to elastic media. By conducting back-propagation and Helmholtz decomposition individually for each receiver wavefield, we obtain corresponding source images by cross-correlating the decoupled P and/or S wavefields. Testing and validation on synthetic models and field data demonstrate the advantages of this method.
Article
Geosciences, Multidisciplinary
Lei Qin, Jamison H. Steidl, Hongrui Qiu, Nori Nakata, Yehuda Ben-Zion
Summary: Subsurface structures play significant roles in seismic ground motion, crustal hydrology, and stability of the built environment. By constraining the temporal changes of subsurface shear wave velocity, valuable information can be provided for these topics and the field of hydrological monitoring using seismic velocity.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Lei Qin, Hongrui Qiu, Nori Nakata, Sizhuang Deng, Alan Levander, Yehuda Ben-Zion
Summary: High-frequency seismic data on Mars are dominated by wind-generated lander vibrations, which are partially radiated to the subsurface. Autocorrelation functions (ACFs) of seismic data on Mars filtered between 1 and 5 Hz show clear phases at around 1.3, 2.6, and 3.9 seconds. Daily changes in arrival times correlate well with ground temperature changes, exhibiting a 5% daily variation and a 50-minute apparent phase delay. Two possible mechanisms are proposed to explain these observations: interference of two predominant spectral peaks at around 3.3 and 4.1 Hz, assumed to be lander resonance modes, and interference of lander vibration and its reflection from an interface approximately 200 meters below the lander. The driving mechanism behind the 50-minute delay is likely thermoelastic strain affecting the lander-ground coupling and subsurface structures. The presented methodology and results contribute to the analysis of ACFs with limited data and enhance our understanding of subsurface materials on Mars.
SEISMOLOGICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Zhendong Zhang, Nori Nakata, Marianne Karplus, Galen Kaip, Jia Yi
Summary: Seismic imaging methods are used to estimate shear-wave speeds and image seismic discontinuities within the polar ice sheet. These parameters are critical for evaluating ice sheet stability and understanding ice dynamics and thermodynamics.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2022)
Article
Geochemistry & Geophysics
Zhendong Zhang, Malcolm C. A. White, Tong Bai, Hongrui Qiu, Nori Nakata
Summary: This study analyzes the behavior of microseismicity induced by hydraulic fracturing in the Montney Formation and performs imaging using distributed acoustic sensing (DAS) data. The lack of 2D/3D variations in the fiber geometry increases the nonuniqueness of the image point location, but P-wave particle motions derived from three-component (3C) geophones data can effectively eliminate the location ambiguity. The updated spatiotemporal distribution of earthquake locations agrees with the fracking schedule, and the predicted travel times also match the observed waveforms.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2023)
