ORCID Profile
0000-0002-1455-2514
Current Organisation
Colorado School of Mines
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Publisher: Society of Exploration Geophysicists
Date: 09-2016
Publisher: Society of Exploration Geophysicists
Date: 09-2021
Publisher: Society of Exploration Geophysicists
Date: 04-09-2023
Abstract: Motivated by existing cabled seismic land-streamer designs, we develop a distributed acoustic sensing (DAS) land-streamer system for high-resolution near-surface seismic data acquisition. The system consists of a DAS interrogator unit (IU), fiber optic cable attached beneath a fire hose assembly for environmental isolation and improved fiber-ground coupling, and a vehicle-mounted accelerated weight-drop source. The DAS land streamer is easily deployed and towed along the ground surface, allowing for spatially dense data acquisition. We present two field tests with the developed hardware to evaluate the DAS land-streamer performance. The first test investigates the effects of hose weight on the surface-deployed fiber and shows that this approach improves fiber-ground coupling and leads to improved signal-to-noise ratio (SNR). The second test demonstrates that the DAS land streamer records waveforms with similar phase and moveouts as those recorded by horizontal geophones, but offers a higher native spatial density advantage than standard geophone arrays, leading to spatially dense waveforms, improved SNR after post-processing, and superior surface-wave acquisition array mobility. Our findings suggest that a DAS land streamer is a promising alternative to traditional geophone-based surveys and may offer several advantages including faster survey acquisition speed and lower field costs due to reduced acquisition hardware requirements. However, methodological limitations include recording a single horizontal ground-motion component, a dependence on favorable fiber-ground coupling conditions, and the upfront cost of IU procurement. A DAS land streamer may be useful in numerous subsurface applications, including (pseudo) 1-D multi-channel analysis of surface waves (MASW) or 2-D surface-wave inversion for shear-wave velocity model estimation for geophysical, geological, geotechnical, and environmental investigations.
Publisher: Society of Exploration Geophysicists
Date: 23-12-2022
Abstract: Long-time marine seismic recordings are becoming more common with the increased use of ocean-bottom nodes (OBNs), which can measure ambient seismic energy at frequencies lower than the typical minimum values in active-source compressed air-gun surveys. Interferometric processing on long-time ambient multicomponent data allows for the extraction of low-frequency (sub-2.0 Hz) responses in virtual source gathers (VSGs). Using 40 days of continuous OBN recordings acquired on a large dense array during a field experiment in the Gulf of Mexico, we find that sub-2.0 Hz surface-wave energy in the computed VSGs is strongly coherent and exhibits an identifiable spatially varying character. In particular, after rotating the data components from a Cartesian geographic into a polar wave-vector reference frame, we find that radial VSGs (i.e., oriented along the vector connecting the virtual source and receiver) clearly indicate that surface-wave propagation is influenced by salt bodies as identified in a colocated active-source survey situated at a minimum of 0.7 km depth below the seafloor, an observation consistent with calculated 0.25–0.50 Hz surface-wave sensitivity kernels. This suggests that low-frequency ambient OBN surface-wave seismology could be important for estimating the long-wavelength elastic material properties (particularly S-wave velocity) and identifying the lateral boundaries of salt bodies without any prior knowledge of subsurface geology.
Publisher: MDPI AG
Date: 11-09-2023
DOI: 10.3390/SU151813574
Publisher: Society of Exploration Geophysicists
Date: 08-2020
Abstract: Since 2006, the SEG Challenge Bowl has brought students together from universities all over the world to compare geoscience and SEG knowledge in a contest of wit and speed.
Publisher: Society of Exploration Geophysicists
Date: 2010
DOI: 10.1190/1.3513744
Publisher: Wiley
Date: 11-03-2018
Publisher: Society of Exploration Geophysicists
Date: 05-2010
Abstract: After working on my geophysics education for several years, I am nearing completion of my master's degree through the IDEA-League, Joint Master's of Applied Geophysics at the University of Edinburgh. Sometimes I sit back and marvel at how I got to this exciting point in my life.
Publisher: Wiley
Date: 02-05-2019
Publisher: Wiley
Date: 29-04-2019
Publisher: Society of Exploration Geophysicists and American Association of Petroleum Geologists
Date: 15-08-2022
Location: Switzerland
No related grants have been discovered for Aaron Joseph Girard.