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Smooth bumps in H/V curves over a broad area from single‐station ambient noise recordings are meaningful and reveal the importance of Q in array processing: The Boumerdes (Algeria) case
Author(s) -
Guillier B.,
Chatelain J.L.,
Hellel M.,
Machane D.,
Mezouer N.,
Ben Salem R.,
Oubaiche E. H.
Publication year - 2005
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2005gl023726
Subject(s) - microtremor , geology , ambient noise level , attenuation , noise (video) , sedimentary rock , seismology , mineralogy , optics , physics , geomorphology , paleontology , sound (geography) , artificial intelligence , computer science , image (mathematics)
Single‐station H/V curves from ambient noise recordings in Boumerdes (Algeria) show smooth bumps around 1 and 3 Hz. A complementary microtremor study, based on two 34 and 134‐meter aperture arrays, evidences that these bumps are indeed real peaks produced by two strong V S contrasts at 37 and 118 meters depth, strongly smoothed by very high S‐wave attenuation in the two sedimentary layers. These two H/V bumps, observed over a broad area, are meaningful and reveal the importance of Q in S‐wave velocity modeling from microtremor array data processing. It also appears that Tertiary rocks should be, at least in some cases, taken into account, together with the Quaternary sediments, to explain single‐station H/V frequency peaks, and therefore that considering only the first 30 m of soil for V S amplification evaluation, as usually recommended, sometimes leads to flaky results by artificially eliminating non‐explained low‐frequency peaks from the analysis.