# Study on Classification Method of Soil Liquefaction Potential Based on Decision Tree
## 6 Criteria Table of Liquefaction Potential Grade
### Evaluation of Rationality of Liquefaction Potential Grade Criterion  
The judgement criteria were applied to the data in database C, which was published by [PERSON] et al. (2013), for verification, and the obtained discrimination results are shown in Table 8. Of the prediction results, 85% of the sites predicted to be low-grade were originally non-liquefied, and 90% of the sites predicted to be high-grade were originally liquefied. This indicated that the assessment accuracy of the liquefied sites and the non-liquefied sites was high for both low and high grades.  
The 235 sites predicted to be intermediate grade included 150 originally liquefied sites and 85 originally non-liquefied sites. A total of 70% of these liquefied sites were predicted  
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline \multirow{2}{*}{**Actual Value**} & \multicolumn{2}{c}{**Predicted Value**} & \multicolumn{1}{c}{\multirow{2}{*}{**Recall**}} \\ \cline{2-2} \cline{4-5}  & **Low** & **Medium-Low** & **Medium-High** & **High** & \\ \hline Low & 47 & 27 & 0 & 0 & 64\% \\ Medium-low & 8 & 90 & 29 & 0 & 71\% \\ Medium-high & 0 & 21 & 101 & 47 & 60\% \\ High & 3 & 0 & 4 & 96 & 93\% \\ Precision & 81\% & 65\% & 75\% & 67\% & 71\% \\ \hline \hline \end{tabular}
\end{table}
Table 7: Confusion matrix for verification of liquefaction potential grade criteria.  
\begin{table}
\begin{tabular}{l l l l l l l} \hline \hline
**Grade** & \multicolumn{2}{c}{**Total (415)**} & \multicolumn{2}{c}{**Non-Liquefaction (128)**} & \multicolumn{2}{c}{**Liquefaction (287)**} \\ \hline Low & \multicolumn{2}{c}{34 (100\%)} & \multicolumn{2}{c}{29 (85\%)} & \multicolumn{2}{c}{5 (15\%)} \\ \hline Medium & \multicolumn{2}{c}{Medium-low} & \multicolumn{1}{c}{235} & \multicolumn{1}{c}{89} & \multicolumn{1}{c}{44} & \multicolumn{1}{c}{150} & \multicolumn{1}{c}{45} \\ \cline{2-6}  & \multicolumn{1}{c}{Medium-high} & \multicolumn{1}{c}{146} & \multicolumn{1}{c}{85} & \multicolumn{1}{c}{41} & \multicolumn{1}{c}{150} \\ \hline High & \multicolumn{2}{c}{146 (100\%)} & \multicolumn{2}{c}{14 (10\%)} & \multicolumn{2}{c}{132 (90\%)} \\ \hline \hline \end{tabular}
\end{table}
Table 8: Accuracy of evaluation for the criteria table of liquefaction potential grade.  
to be medium to high grade, while the non-liquefied sites were predicted roughly evenly to be medium-low and medium-high grades.  
As shown in Table 8, the prediction accuracies of the low and high grades were high (more than 85%). After the segmentation of the middle grade, the accuracy of the middle and high grades was also ideal, but the distinction ability between the liquefied and non-liquefied sites of the middle and low grades was not high, which was directly related to the high confusion of the liquefied and non-liquefied sites near the 50% liquefaction probability critical line. In a follow-up study, this part of the data will be deeply analyzed. Other parameters can be further introduced into the judgement criteria to distinguish the middle-grade data more accurately and further improve the practicability and accuracy of the method.