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The motivation of this study stems from a retaining wall made of waste tires. The wall did not suffer any earthquake or tsunami-induced damage during the 2011 Off the Pacific Coast of Tohoku Earthquake, Japan. This paper deals with a case study on this tire retaining wall. Results from a series of field and laboratory investigations are first described. A numerical simulation is also described in which whole tires were used as protective layers in an embankment. The results show that confining effect of each tire, friction between the tires, ductility, and damping inherent in tires contribute towards the excellent performance of the retaining wall during the earthquake loading. The case study also reveals that it is the isolation mechanism due to the vibration absorption capability of rubber particles in tires, which could protect tire retaining structure during the earthquake. [ABSTRACT FROM AUTHOR]

To date, multiple ground-motion prediction equations (GMPEs) for the significant duration (DS) of shallow crustal earthquakes have been proposed, but there are few GMPEs for subduction intraslab and interface earthquakes in Japan, and corresponding spatial correlation models have not been published. To address this issue, we first select ground-motion records with moment magnitude 4 ≤ Mw ≤ 9, rupture distance Rrup ≤ 300 km, and peak ground acceleration ≥ 10 gal based on the K-NET and KiK-net databases. Then, for intraslab and interface earthquakes in the subduction zone, based on previous works, the traditional source duration term is simplified, a depth term is added, and new GMPEs for DS of earthquakes in the subduction zone in Japan are developed. The rationality and reliability of the prediction model proposed in this study are verified by residual analysis and comparison with the previous models. Finally, according to the intra-event residuals, a spatial correlation model of DS is established by using a semivariogram and exponential model. The results show that DS of subduction interface earthquakes is larger than that of subduction intraslab earthquakes on the whole, but the spatial correlation coefficient of subduction interface earthquakes decreases more slowly with increasing separation distance than that of subduction intraslab earthquakes, and the significant duration of the spatial correlation is related to site effects and path effects. The results provide a reference for the development of GMPEs based on nonergodic assumptions, regional seismic hazard analysis and loss assessment. [ABSTRACT FROM AUTHOR]

Based on the observed strong-motion records of K-NET and KiK-net, we utilized 1,065 earthquake observation stations installed throughout Japan, gathering more than 140,000 recordings for weak motions with a peak ground acceleration (PGA) of less than 100 cm/s2 and more than 5,300 records for strong motions with a PGA of more than 100 cm/s2. These 1,065 sites detected at least one recording with a PGA value greater than 100 cm/s2. These recordings were used to quantify the horizontal-to-vertical spectral ratio (HVSR) difference between weak and strong shakings. Based on the observations, the discrepancy in HVSR between weak and strong shakings can be depicted as a shift both in the frequency and amplitude axes in the logarithmic coordinate system. This kind of shift can be favorably interpreted by an established diffused field theory of the HVSR of earthquakes. Based on the concept of shifts, new empirical functions are proposed to modify the averaged HVSR in linear cases in order to acquire the HVSR in nonlinear regimes. Subsequently, an improved vertical amplification correction function, which considers the time-averaged shear wave velocity down to 30 m, was used to convert the modified HVSR into the horizontal site amplification factor (HSAF) in nonlinear regimes. The new methodology adopted in this study, which does not require detailed soil layer information, is convenient for obtaining the HSAF by considering empirically obtained nonlinear soil behaviors. [ABSTRACT FROM AUTHOR]

Ground motion prediction equations (GMPEs) have a major impact on seismic hazard estimates, because they control the predicted amplitudes of ground shaking. The prediction of ground-motion amplitudes due to mega-thrust earthquakes in subduction zones has been hampered by a paucity of empirical ground-motion data for the very large magnitudes (moment magnitude ( M) $$>$$ 7) of most interest to hazard analysis. Recent data from Tohoku M9.0 2011 earthquake are important in this regard, as this is the largest well-recorded subduction event, and the only such event with sufficient data to enable a clear separation of the overall source, path and site effects. In this study, we use strong-ground-motion records from the M9 Tohoku event to derive an event-specific GMPE. We then extend this M9 GMPE to represent the shaking from other M $$>$$ 7 interface events in Japan by adjusting the source term. We focus on events in Japan to reduce ambiguity that results when combining data in different regions having different source, path and site effect attributes. Source levels (adjustment factors) for other Japanese events are determined as the average residuals of ground-motions with respect to the Tohoku GMPE, keeping all other coefficients fixed. The mean residuals (source terms) scale most steeply with magnitude at the lower frequencies; this is in accord with expectations based on overall source-scaling concepts. Interpolating source terms over the magnitude range of 7.0-9.0, we produce a GMPE for large interface events of M7- M9, for NEHRP B/C boundary site conditions (time-averaged shear-wave velocity of 760 m/s over the top 30 m) in both fore-arc and back-arc regions of Japan. We show how these equations may be adjusted to account for the deeper soil profiles (for the same value of $$\hbox {V}_\mathrm{S30})$$ in western North America. The proposed GMPE predicts lower motions at very long periods, higher motions at short periods, and similar motions at intermediate periods, relative to the simulation-based GMPE model of Atkinson and Macias () for the Cascadia subduction zone. [ABSTRACT FROM AUTHOR]