# README – Final_SC_station_data_phase1_and_2.csv

## Overview

This file contains seismic site characterisation results for all stations deployed during Phase 1 and Phase 2 of the WA Array network across southwestern Western Australia. Each row corresponds to one seismic station and summarises the key site parameters derived from surface wave analysis (array methods or HVSR) used to assign an Australian Seismic Site Classification Model (ASSCM) site class.

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## Column Definitions

| Column | Definition | Unit |
|--------|-----------|------|
| `CODE` | Unique station identifier code 
| `Network` | Seismic network code to which the station belongs 
| `Latitude` | Geographic latitude of the station location (negative = south) | Decimal degrees (°) |
| `Longitude` | Geographic longitude of the station location (positive = east) | Decimal degrees (°) |
| `ASSCM_SC` | Site class assigned following the Australian Seismic Site Classification Model (ASSCM); may indicate a transitional class (e.g. CD, DE) where the site straddles two class boundaries 
| `ASSCM_VS` | Time-averaged shear-wave velocity up to 30m depth (VS30) relevant under the ASSCM framework, used to determine the ASSCM site class | m/s |
| `USGS_VS` | Time-averaged shear-wave velocity up to 30 m depth (VS30) estimated using the USGS topographic slope proxy | m/s |
| `f0` | Fundamental site resonance frequency derived from the HVSR peak | Hz |
| `E_bed` | Depth to bedrock (engineering bedrock, defined by a velocity threshold > 760 m/s) | m |
| `G_bed` | Depth to bedrock (Geology bedrock, defined by a velocity threshold > 1500 m/s) | m |
| `VS30` | Measured time-averaged shear-wave velocity up to 30 m depth (VS30), calculated directly from the inverted velocity profiles | m/s |
| `SC` | Final assigned site class used for reporting purposes (may differ from ASSCM_SC) 
| `Measurment_type` | Method used to derive the site characterisation result: `Array` = multi-station surface wave array method (e.g. SPAC/FK); `HVSR` = single-station horizontal-to-vertical spectral ratio analysis 

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## Notes

- Stations with a transitional site class (e.g. `CD`, `DE`) in `ASSCM_SC` or `SC` indicate that the site velocity profile sits close to the boundary between two classes; 
- `ASSCM_VS` is the velocity metric defined in the ASSCM framework and may correspond to VS30 or a velocity averaged to a shallower depth, depending on the depth to bedrock at the site.
- `USGS_VS` is a proxy estimate derived from topographic slope and should be treated as indicative only; it is provided for comparison and is not used for the primary site classification.
- `E_bed` values are derived from the inverted shear-wave velocity profile and represent the depth at which velocity exceeds the engineering bedrock threshold (typically 760 m/s). Where bedrock was not encountered within the inversion depth range, values may be reported as the maximum profiled depth.
- `G_bed` values are derived from the inverted shear-wave velocity profile and represent the depth at which velocity exceeds the Geology bedrock threshold (typically 1500 m/s). Where bedrock was not encountered within the inversion depth range, values may be reported as the maximum profiled depth.
