# Factors That Affect Liquefaction-Induced Lateral Spreading in Large Subduction Earthquakes
## 3 Validation of the Numerical Methodology
### Validation with Historical Cases
#### 3.2.1 Description of Field Conditions  
For the Lo Rojas site, there is reliable information on layer stratification, in situ testing, and laboratory tests documented in [PERSON] et al. (2017) [22] and [PERSON] et al. (2017) [41]. Likewise, the papers of [PERSON] (1992) [42] and [PERSON] (2014) [19] show test field data from the Matanuska site.  
For the Lo Rojas site, the same modeling section selected by [PERSON] et al. (2017) [22] was used for validation. This geotechnical model was developed according to the bathymetry and field test information provided by the Ports Department of the Ministry of Public Works. According to [PERSON] et al. (2017) [41], the soil profile was composed of four soil units, from top to bottom: poorly graded sand (\(\sim\)10 m thick), clayey sand (\(\sim\)9 m thick), high plasticity clay (\(\sim\)5 m thick), and low plasticity clay (down to 70 m deep before a highly cemented soil). Several laboratory tests were conducted to obtain the mechanical parameters for the soil layers: monotonic triaxial, cyclic triaxial, and column shear test (details in [PERSON] et al. (2017) [22] and [PERSON] et al. (2017) [41]). Table 6 shows the calibrated parameters used for the Lo Rojas model in this study. Using the pore water pressure-based criteria by [PERSON] et al. 2004 [43], the numerical results show that the upper poorly graded sand liquefied as the excess pore pressure ratio (r\({}_{\text{u}}\)) reached 1.0 after 20 seconds during the seismic event.  
For the Matanuska site, the modeling section was developed considering the boreholes taken at the Railroad Bridge Mile Post near the Matanuska River ([PERSON] and [PERSON] (1992) [42]). According to [PERSON] and [PERSON] (2014) [19] the selected soil profile was composed, from top to bottom, of gravel sand (\(\sim\)6 m thick), well-graded gravel (\(\sim\)2 m thick), poorly graded sand (\(\sim\)5 m thick), clayed sand (\(\sim\)9 m thick), and low plasticity clay (down to 70 m deep before a highly cemented soil). Table 7 shows the parameters used in the Matanuska model. Figure 15 shows the soil geotechnical layout at both sites.  
The Lo Rojas and the Matanuska sites have a stratigraphy of alluvial sediments characterized by upper layers of liquefiable sands underlain by clay. For both sites, default values of Cyclid1D were adopted for the contraction, dilation, and liquefaction parameters (c1, c2, d1, d2, liq), and the number of yield surfaces ([PERSON] et al. (2015) [26]). The coefficient of lateral pressure was estimated using [PERSON]'s equation ([PERSON] (1944) [37]). Mass density was estimated from the Standard Penetration Test (SPT) sounding from [PERSON] et al. (2017) [22] for the Lo Rojas case, and the SPT sounding from [PERSON] and [PERSON] (2014) [19] for the Matanuska case. Shear wave velocities were obtained from geophysical field tests from [PERSON] et al. (2017) [41] for the Lo Rojas case, and using [PERSON] (2007) [44] correlations for the Matanuska case. For the clays in the Lo Rojas site, peak shear strain, friction angle, and undrained shear strength were obtained from the geotechnical model of [PERSON] et al. (2017) [22] and [PERSON] et al. (2017) [41] which were based on monotonic and dynamic  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Unit [USCS]** & **Depth [m]** & \(\rho\) [kN/m\({}^{3}\)] & **Vs [m/s]** & **coeff** & **k\({}_{\text{0}}\)** & \(\Phi\) [\({}^{\circ}\)] & **PT [\({}^{\circ}\)]** & **Su [kPa]** & **K [m/s]** & **NYS** \\ \hline SP & 0-10 & 16 & 203 & 0.50 & 0.50 & 31.4 & 26.5 & - & \(3.3\times 10^{-5}\) & 25 \\ SC & 10–20 & 20 & 224 & 0.50 & 0.65 & 35 & 26.5 & - & \(6.6\times 10^{-5}\) & 20 \\ CH & 20-35 & 20 & 224 & 0 & 0.65 & - & - & 75 & \(1.0\triaxial tests. For the Matanuska site, we chose pre-defined Cyclic 1D values based on the information from the boreholes documented in [PERSON] (1992) [42] and [PERSON] (2014) [19].