Methodology
How observations become a useful, accountable map.
Collection and validation
Server jobs collect USGS every minute and NASA/GDACS every 15 minutes. Requests have timeouts, retry backoff and rate-limit handling. Each record must have a source ID, a usable timestamp and valid geometry. Future timestamps beyond a five-minute clock tolerance are rejected. Invalid records are counted; valid records remain usable.
Normalization and revision history
Provider-specific adapters preserve source identities, units and raw input. PostgreSQL upserts use unique provider event IDs and source-content hashes. Changed records are stored in a revision table from the time TerraPulse first observes them. Different agencies are not automatically merged based on proximity. Cross-provider totals can count multiple reports about the same real-world event.
Country assignment
Point-in-polygon tests use Natural Earth 1:50m land boundaries. Place-name strings are not used to assign countries. Offshore and non-point events remain unassigned. This approximation is suitable for discovery, not legal boundary determinations. Country statistics exclude unassigned observations.
Filters and statistics
The explorer retains a rolling past 30 days. USGS filters use occurrence time; NASA filters use the latest reported geometry time. Magnitude and depth filters apply only to USGS earthquakes. Earthquake statistics count unique USGS IDs. Shallow is below 70 km; intermediate is 70 to below 300 km; deep is 300 km or more. Unknown magnitudes are never treated as zero.
Time and freshness
All timestamps are stored in UTC. The explorer can display UTC or the browser timezone; a precise incident-region timezone is not inferred without a reliable lookup. Provider feed generation time, provider event update time and collection time are separate. If a source fails, its last successful observations remain visible with an age and error indication.
Geometries and limitations
Original Point, Polygon, MultiPolygon and LineString geometries are supported. Geometry anchor coordinates are used for map navigation only. Non-point shapes are not replaced by fabricated single locations. NASA lines represent reported positions, not forecast tracks. Marker sizes are magnitude symbols, not affected areas.