TY  - JOUR
A1  - Zhu, Chuanbin
A1  - Cotton, Fabrice
A1  - Kawase, Hiroshi
A1  - Händel, Annabel
A1  - Pilz, Marco
A1  - Nakano, Kenichi
T1  - How well can we predict earthquake site response so far?
BT  - site-specific approaches
JF  - Earthquake spectra : the professional journal of the Earthquake Engineering Research Institute
N2  - Earthquake site responses or site effects are the modifications of surface geology to seismic waves. How well can we predict the site effects (average over many earthquakes) at individual sites so far? To address this question, we tested and compared the effectiveness of different estimation techniques in predicting the outcrop Fourier site responses separated using the general inversion technique (GIT) from recordings. Techniques being evaluated are (a) the empirical correction to the horizontal-to-vertical spectral ratio of earthquakes (c-HVSR), (b) one-dimensional ground response analysis (GRA), and (c) the square-root-impedance (SRI) method (also called the quarter-wavelength approach). Our results show that c-HVSR can capture significantly more site-specific features in site responses than both GRA and SRI in the aggregate, especially at relatively high frequencies. c-HVSR achieves a "good match" in spectral shape at similar to 80%-90% of 145 testing sites, whereas GRA and SRI fail at most sites. GRA and SRI results have a high level of parametric and/or modeling errors which can be constrained, to some extent, by collecting on-site recordings.
KW  - Site response
KW  - site effects
KW  - HVSR
KW  - ground response analysis
KW  - square-root-impedance
KW  - earthquake
Y1  - 2022
U6  - https://doi.org/10.1177/87552930211060859
SN  - 8755-2930
SN  - 1944-8201
VL  - 38
IS  - 2
SP  - 1047
EP  - 1075
PB  - Sage Publ.
CY  - Thousand Oaks
ER  - 
TY  - JOUR
A1  - Ktenidou, Olga-Joan
A1  - Roumelioti, Zafeiria
A1  - Abrahamson, Norman
A1  - Cotton, Fabrice
A1  - Pitilakis, Kyriazis
A1  - Hollender, Fabrice
T1  - Understanding single-station ground motion variability and uncertainty (sigma)
BT  - lessons learnt from EUROSEISTEST
JF  - Bulletin of earthquake engineering : official publication of the European Association for Earthquake Engineering
N2  - Accelerometric data from the well-studied valley EUROSEISTEST are used to investigate ground motion uncertainty and variability. We define a simple local ground motion prediction equation (GMPE) and investigate changes in standard deviation (σ) and its components, the between-event variability (τ) and within-event variability (φ). Improving seismological metadata significantly reduces τ (30–50%), which in turn reduces the total σ. Improving site information reduces the systematic site-to-site variability, φ S2S (20–30%), in turn reducing φ, and ultimately, σ. Our values of standard deviations are lower than global values from literature, and closer to path-specific than site-specific values. However, our data have insufficient azimuthal coverage for single-path analysis. Certain stations have higher ground-motion variability, possibly due to topography, basin edge or downgoing wave effects. Sensitivity checks show that 3 recordings per event is a sufficient data selection criterion, however, one of the dataset’s advantages is the large number of recordings per station (9–90) that yields good site term estimates. We examine uncertainty components binning our data with magnitude from 0.01 to 2 s; at smaller magnitudes, τ decreases and φ SS increases, possibly due to κ and source-site trade-offs Finally, we investigate the alternative approach of computing φ SS using existing GMPEs instead of creating an ad hoc local GMPE. This is important where data are insufficient to create one, or when site-specific PSHA is performed. We show that global GMPEs may still capture φ SS , provided that: (1) the magnitude scaling errors are accommodated by the event terms; (2) there are no distance scaling errors (use of a regionally applicable model). Site terms (φ S2S ) computed by different global GMPEs (using different site-proxies) vary significantly, especially for hard-rock sites. This indicates that GMPEs may be poorly constrained where they are sometimes most needed, i.e., for hard rock.
KW  - Ground motion
KW  - Variability
KW  - Uncertainty
KW  - Single station sigma
KW  - Site response
Y1  - 2018
U6  - https://doi.org/10.1007/s10518-017-0098-6
SN  - 1570-761X
SN  - 1573-1456
VL  - 16
IS  - 6
SP  - 2311
EP  - 2336
PB  - Springer
CY  - Dordrecht
ER  -