# README – VS_SC_phase1_and_2 (median_vs_station_*.dat files)

## Overview

This folder contains one file per station giving the median shear-wave velocity (Vs) depth profile derived from inversion of HVSR and surface wave dispersion data. Each file represents the median model extracted from the accepted models for that station and provides a continuous 1-D Vs profile from the surface down to the maximum inversion depth. These profiles are the primary input used to compute VS30, engineering bedrock depth, and ASSCM site class assignments reported in `Final_SC_station_data_phase1_and_2.csv`.

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## File Naming Convention

Files are named using the format:

```
median_vs_station_<STATION_CODE>.dat
```

where `<STATION_CODE>` matches the `CODE` field in `Final_SC_station_data_phase1_and_2.csv`.

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## File Format

- **Columns:** 4 columns per row, in the following fixed order:

| Column position | Variable | Definition | Unit |
|----------------|----------|-----------|------|
| 1 | `Longitude` | Geographic longitude of the station (positive = east) | Decimal degrees (°) |
| 2 | `Latitude` | Geographic latitude of the station (negative = south) | Decimal degrees (°) |
| 3 | `Depth` | Depth below the surface at which the velocity value applies | m |
| 4 | `Vs` | Median shear-wave velocity at the corresponding depth | m/s |

**Example row:**
```
116.6529    -33.50367    0.0    413.15847061184
```

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## Notes

- Depth increments are 0.1 m, sampled uniformly from 0.0 m to the maximum inversion depth (typically 100–150 m depending on the station).
- Longitude and latitude are constant throughout each file (all rows correspond to a single station location).
- The coordinate system is WGS84 geographic (EPSG:4326).
