Comparison of near-field surface and borehole ground motion observed during the Kumamoto MW7.0 earthquake
Luo Cheng
Xie Junju
Wen Zengping
Abstract：We used the records of 82 near-field strong motion stations (KiK-net),which are within 200 km to the rupture fault of the Kumamoto MW7.0 earthquake,as database to derive near-field horizontal peak ground acceleration PGA,peak ground velocity PGV and spectra acceleration (period T=0.2,1,2,3,5,10 s),after baseline correction we further compared them with the NGA-West2 ground motion model predictions.We investigated the attenuation and residuals distribution characteristics of these intensity measures (IMs),and shallow siteamplification effects by comparing surface and borehole ground motion records.The following conclusions can be drawn from our study:In the boreholes,NGA-West2 predictions are obviously greater than observations of PGA and T=0.2 s spectra acceleration,but close to the measured value in long-period IMs (spectra acceleration with T=1,2,3 s) and PGV.On surface,the residuals of observed PGV and T=0.2-3 s spectra acceleration show linear decrease tendency with the increase of vS30,but the site effects affect little on the long-period spectra acceleration.Surface records are greater than borehole in PGA,PGV and T=0.2,1,2 s spectra acceleration,and the amplification effects decrease with the increase of shallow site shear velocity;whereas the site amplification has little effects on the long-period spectra acceleration with T=3,5,10s.
Keywords：Kumamoto earthquakestrong motionnear-fieldborehole recordings
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：13( 108-120 )