Seismic Ground Roll Absorption and Reemission by Sand Dunes. Issue 7 (5th July 2018)

• Record Type: Journal Article
• Authors: Arran, M. I.; Vriend, N. M.; Muyzert, E.
• Is Part Of: Journal of geophysical research. Volume 123:Issue 7(2018)
• Page Start: 5675
• Page End: 5689
• Publication Date: 2018-07-05
• Subjects: exploration geophysics -- near‐surface -- surface waves -- Rayleigh waves -- barchans -- resonance; Geomagnetism -- Periodicals; Geochemistry -- Periodicals; Geophysics -- Periodicals; Earth sciences -- Periodicals; 551.1
• DOI: 10.1029/2018JB015580
• Languages: English
• ISSNs: 2169-9313

Abstract

Abstract: Ground roll is a significant source of noise in land seismic data, with crossline scattered ground roll particularly difficult to suppress. This noise arises from surface heterogeneities lateral to the receiver spread, and in desert regions sand dunes are a major contributor. However, the nature of this noise is poorly understood, preventing the design of more effective data acquisition or processing techniques. Here we present numerical simulations demonstrating that a barchan sand dune acts as a resonator, absorbing energy from ground roll and reemitting it over an extensive period of time. We derive and validate a mathematical framework that quantitatively describes the properties of the emitted waves and demonstrate that wave amplitude is estimable from easily measurable bulk properties of the dune. Having identified regions in time, space, and frequency space at which noise will be more significant, we propose reducing dune‐scattered noise through careful survey design and data processing. In particular, we predict that seismic noise will be lower upwind of barchan dunes, and at frequencies far from a resonant frequency 2 c S / H, for dune height H and typical seismic velocity within the dune c S . This work is especially relevant to seismic acquisition in the vicinity of a dune field, where scattered noise appears incoherent and difficulties arise with alternative approaches to noise suppression. Key Points: In seismic surveys, sand dunes will exhibit absorption and reemission of ground roll, causing noise We present a simple analytic model that successfully predicts the amplitude of this noise The noise is lower upwind of a barchan dune and away from a resonant frequency of the dune