Evo Earthquake Distance

Earthquake Distance to Plate Boundary Analysis

This skill finds the earthquake that occurred furthest from a tectonic plate boundary within the plate itself, using GeoPandas projections.

Workflow

1. Load plate polygon geometry from PB2002_plates.json
2. Load all boundary segments for the plate from PB2002_boundaries.json
3. Load earthquake data from USGS GeoJSON format
4. Filter earthquakes to those within the plate polygon (point-in-polygon in EPSG:4326)
5. Project both earthquake points and boundary geometry to EPSG:4087 (equidistant cylindrical)
6. Compute minimum distance from each earthquake to the merged boundary
7. Find the earthquake with maximum distance
8. Output result as JSON with required fields

Usage Example

pythonCopy code
import sys
sys.path.insert(0, '/app/environment/skills/evo-earthquake-distance/scripts')
from utils import find_furthest_earthquake, validate_output

# Run end-to-end analysis
result = find_furthest_earthquake(
    earthquakes_path='/root/earthquakes_2024.json',
    plates_path='/root/PB2002_plates.json',
    boundaries_path='/root/PB2002_boundaries.json',
    output_path='/root/answer.json',
    plate_code='PA',
    target_crs='EPSG:4087'
)

# Validate output
validate_output('/root/answer.json')

Key Design Decisions

• EPSG:4087 (World Equidistant Cylindrical) is used for distance computation as it provides reasonable distance accuracy across the entire Pacific plate
• Point-in-polygon testing is done in EPSG:4326 to avoid projection distortion at plate edges
• All boundary segments containing the plate code are included (not just one neighbor)
• Time conversion: USGS timestamps are in milliseconds, divided by 1000 before conversion to ISO 8601
• Pacific plate is a MultiPolygon due to antimeridian crossing; handled automatically by GeoPandas

Utility Functions

• load_plate_polygon(plates_path, plate_code) - Load unified plate polygon
• load_plate_boundaries(boundaries_path, plate_code) - Load merged boundary geometry
• load_earthquakes(earthquakes_path) - Load earthquakes as GeoDataFrame
• filter_earthquakes_in_plate(earthquakes_gdf, plate_geom) - Spatial filter
• compute_distances_to_boundary(earthquakes_gdf, boundary_geom, target_crs) - Distance computation
• ms_to_iso8601(time_ms) - Timestamp conversion
• find_furthest_earthquake(...) - End-to-end entry point
• validate_output(output_path) - Output validation