## 5 Results and Discussion
### Application for Site-Specific Characterization
This was demonstrated by [PERSON] and [PERSON] (2021) [73], through utilizing refraction microtremors in two-dimensional shear wave velocity mapping, thereby extending subsurface characterization and mapping lateral variations between spot boreholes. Alternatively, shear wave velocity surveys might not be feasible in some urban areas, due to a lack of availability of open space to lay the linear geophone array, which is a technical requirement of some geophysical tests. These sites instead might have robust borehole survey results acquired before the building's construction. Compilation of these SPT datasets can be utilized and converted to shear wave values, to produce or refine seismic microzonation maps. The derived empirical correlations of V\({}_{\rm s}\) and reliable static field data such as the SPT N-value can be an alternative way to determine these seismic parameters, such as the V\({}_{\rm s30}\). However, an important caveat, before the application of the proposed empirical relations, is to ensure the reliability of obtained SPT data to estimate the corresponding V\({}_{\rm s}\) values. On the other hand, the processing of geophysical data to acquire V\({}_{\rm s}\) must also be performed with utmost caution, to minimize uncertainty before applying it for basic soil strength classification. Furthermore, these empirical correlations must be applied with \begin{table}
\begin{tabular}{c c c} \hline \hline
**Soil Description** & **V\({}_{\rm s}\) (m/s)** & **SPT N-value** \\ \hline Very soft to soft soils & \textless{}180 m/s & \textless{}10 \\ Stiff soils & 180–360 m/s & 10–45 \\ Very dense soils & 360–760 m/s & \textgreater{}45 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Simplified correlation of V\({}_{\rm s}\) and SPT-N for different soil strength classifications in this study. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Location** & **Coordinates** & \begin{tabular}{c} **Generalized Soil** \\ **Profile Description** \\ \end{tabular} & \
\begin{tabular}{c} **V\({}_{\rm s30}\) Using Proposed** \\ **Correlation for All Soil Types** \\ \end{tabular} &
\begin{tabular}{c} **Site Class Per** \\ **NSCP (2015)** \\ \end{tabular} \\ \hline J. A. Santos High School, & 120.972674\({}^{\circ}\) E, & poorly graded & & \\ Manila City & 14.597179\({}^{\circ}\) N & to silty sand, silt & 187.30 & Class D \\ T. Paez Elementary School, & 120.966613\({}^{\circ}\) E & silt, well-graded & & \\ Manila City & 14.630679\({}^{\circ}\) N & and silty sand & 243.10 & Class D \\ Among Rodriguez & 120.949242\({}^{\circ}\) E & silty gravel, & & \\ Elementary School, & 14.671821\({}^{\circ}\) N & silty sand, clays & 320.08 & Class D \\ Talagos I Elementary School, & 120.932371\({}^{\circ}\) E & poorly graded & & \\ Navotas City & 14.673729\({}^{\circ}\) N & to silty sand, silt & 274.71 & Class D \\ Jose Rizal Elementary School, & 120.997418\({}^{\circ}\) E & well graded to & 330.05 & Class D \\ Pasay City & 14.543973\({}^{\circ}\) N & silty sand, silt & & \\ V.E. Fugoso Memorial & 121.118325\({}^{\circ}\) E & high plasticity silt, & & \\ Elementary School, & 14.666042\({}^{\circ}\) N & low plasticity clay & 225.04 & Class D \\ Marikina City & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Typical average shear wave velocity to a 30-m depth (V\({}_{\rm s30}\)) of all soils at various locations in Metro Manila. cution and with consideration to the geologic, geomorphologic, and geotechnical setting of an area. Areas with a very different environment must utilize other empirical functions that are more suitable to the locality.