000020176 001__ 20176
000020176 005__ 20170118182358.0
000020176 04107 $$aeng
000020176 046__ $$k2017-01-09
000020176 100__ $$aYamanaka, Hiroaki
000020176 24500 $$aA Proposal of An Index Based on Microtremor Measurements To Discriminate Irregularity of Subsurface Boundary

000020176 24630 $$n16.$$pProceedings of the 16th World Conference on Earthquake Engineering
000020176 260__ $$b
000020176 506__ $$arestricted
000020176 520__ $$2eng$$aThe subject of this article is to see if a spatial variation of horizontal to vertical spectral ratios (HVSRs) of microtremors can be regarded as a proxy of an irregularity effect of sediment-basement interface in order to readily discriminate a flat layer site from an irregular layer site. We performed 3 investigations: 1) we evaluated coefficients of variation (CVs) of HVSRs’ peak periods at 4 sites based on densely mobile microtremor measurements, 2) evaluated sensitivity for CVs by numerical simulations for wave propagation with complex media, and 3) compared power spectral density estimated from CVs with that calculated from subsurface structure model. We found that CVs were 1) obviously different between flat layer sites and irregular layer sites in observed microtremors, and 2) sensitive to the slope angle of sediment interfaces. We also found that 3) CVs were related to the irregularity of the basement interfaces. As a result, we propose that CVs of 0.1 is a threshold to sort out flat layer sites where amplification factor can be approximately calculated assuming stratified media.

000020176 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000020176 653__ $$amicrotremors, H/V spectral ratio, peak period, coefficient of variation, power spectral density

000020176 7112_ $$a16th World Conference on Earthquake Engineering$$cSantiago (CL)$$d2017-01-09 / 2017-01-13$$gWCEE16
000020176 720__ $$aYamanaka, Hiroaki$$iTakesue, Kojiro$$iKato, Kenichi$$iWatanabe, Tetsushi$$iMotoki, Kentaro$$iIiba, Masanori
000020176 8560_ $$ffischerc@itam.cas.cz
000020176 8564_ $$s2084180$$uhttps://invenio.itam.cas.cz/record/20176/files/691.pdf$$yOriginal version of the author's contribution as presented on USB, paper 691.
000020176 962__ $$r16048
000020176 980__ $$aPAPER