Browsing Institutt for elektroniske systemer by Journals "Geophysics"
Now showing items 1-13 of 13
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An adapted eigenvalue-based filter for ocean ambient noise processing
(Peer reviewed; Journal article, 2020)Accurate approximations of Green’s functions retrieved from the correlations of ambient noise require a homogeneous distribution of random and uncorrelated noise sources. In the real world, the existence of highly coherent, ... -
Average Qp and Qs estimation in marine sediments using a dense receiver array
(Peer reviewed; Journal article, 2023) -
Comparing the broadband acoustic frequency response of single, clustered and arrays of marine air guns
(Peer reviewed; Journal article, 2020)Field data acquired from a seismic vessel by a seabed hydrophone is used to analyze the broadband response (10 Hz to 62.5 kHz) for various source configurations: single air guns, clustered air guns, and a full array ... -
Distributed acoustic sensing for near-surface imaging using submarine telecommunication cable: A case study in the Trondheimsfjord, Norway
(Journal article; Peer reviewed, 2021) -
Distributed acoustic sensing of ocean-bottom seismo-acoustics and distant storms: A case study from Svalbard, Norway
(Peer reviewed; Journal article, 2023)Distributed acoustic sensing (DAS) leverages an ocean-bottom telecommunication fiber-optic cable into a densely sampled array of strain sensors. We demonstrate DAS applications to passive acoustic monitoring (PAM) through ... -
Estimating source signatures from source-over-spread marine seismic data
(Journal article; Peer reviewed, 2018)Recent developments in marine seismic acquisition include deploying a source vessel above a towed-streamer spread. We have developed an inversion algorithm to estimate source signatures for such acquisition configurations, ... -
Near-surface characterization using shear-wave resonances: A case study from offshore Svalbard, Norway
(Peer reviewed; Journal article, 2024)Shear-wave (S-wave) resonances are typically observed when the surficial marine sediments over a rock substrate have relatively low S-wave velocities. We observe these phenomena using ocean-bottom fiber-optic distributed ... -
Numerical study of the effect of cement defects on flexural-wave logging
(Journal article; Peer reviewed, 2019)Cement-bond evaluation is needed for new wells and plug and abandonment activities. The ultrasonic leaky Lamb-wave (also called the flexural-wave) technique, in combination with the pulse-echo technique, has been widely ... -
On low frequencies emitted by air guns at very shallow depths - An experimental study
(Journal article; Peer reviewed, 2019)In marine seismic acquisition, the enhancement of frequency amplitudes below 5 Hz is of special interest because it improves imaging of the subsurface. The frequency content of the air gun, the most commonly used marine ... -
Quick clay monitoring using distributed acoustic sensing: A case study from Rissa, Norway
(Peer reviewed; Journal article, 2023)Quick clay avalanche is one of the most devastating landslide types worldwide. Hence, an early warning system is in demand to mitigate the fatal consequences caused by such events. To address this, distributed acoustic ... -
Repeatability of high-resolution 3D seismic data
(Journal article; Peer reviewed, 2018)High-resolution 4D (HR4D) seismic data have the potential for improving the current state-of-the-art in detecting shallow (≤ 500 − 1000 m below seafloor) subsurface changes on a very fine scale (approximately 3–6 m). ... -
Three-dimensional magnetotelluric modelling in a mixed space-wavenumber domain
(Peer reviewed; Journal article, 2022)We have developed a new 3D magnetotelluric modeling scheme in a mixed space-wavenumber domain. The modeling scheme is based on using a 2D Fourier transform along two horizontal directions to solve a vector-scalar potential ... -
Tube-wave monitoring as a method to detect shear modulus changes around boreholes: A case study
(Peer reviewed; Journal article, 2021)Monitoring the shear modulus of formations around boreholes is of interest for various applications, ranging from near-surface investigation to reservoir monitoring. Downhole logging tools and borehole seismic are common ...