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Acquisition and processing pitfall with clipped traces in surface-wave analysis

Gao, Lingli; Pan, Yudi

Abstract: Multichannel analysis of surface waves (MASW) is widely used in estimating near-surface shear (S)-wave velocity. In the MASW method, generating a reliable dispersion image in the frequency–velocity (f–v) domain is an important processing step. A locus along peaks of dispersion energy at different frequencies allows the dispersion curves to be constructed for inversion. When the offsets are short, the output seismic data may exceed the dynamic ranges of geophones/seismograph, as a result of which, peaks and (or) troughs of traces will be squared off in recorded shot gathers. Dispersion images generated by the raw shot gathers with clipped traces would be contaminated by artifacts, which might be misidentified as Rayleigh-wave phase velocities or body-wave velocities and potentially lead to incorrect results. We performed some synthetic models containing clipped traces, and analyzed amplitude spectra of unclipped and clipped waves. The results indicate that artifacts in the dispersion image are dependent on the level of clipping. A real-world example also shows how clipped traces would affect the dispersion image. All the results suggest that clipped traces should be removed from the shot gathers before generating dispersion images, in order to pick accurate phase velocities and set reasonable initial inversion models.

Zugehörige Institution(en) am KIT Geophysikalisches Institut (GPI)
Publikationstyp Zeitschriftenaufsatz
Jahr 2016
Sprache Englisch
Identifikator DOI: 10.1016/j.jappgeo.2015.12.004
ISSN: 0926-9851, 1879-1859
KITopen ID: 1000059091
Erschienen in Journal of applied geophysics
Band 125
Seiten 1-6
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