> ## Documentation Index
> Fetch the complete documentation index at: https://www.worldmonitor.app/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Natural Disaster Tracking

> Multi-source natural disaster monitoring via GDACS and NASA EONET with deduplication and filtering for earthquakes, wildfires, and cyclones.

The Natural layer combines two authoritative sources for comprehensive disaster monitoring, providing real-time alerts with severity assessments and satellite-derived event detection.

## GDACS (Global Disaster Alert and Coordination System)

UN-backed disaster alert system providing official severity assessments:

| Event Type       | Code | Icon       | Sources           |
| ---------------- | ---- | ---------- | ----------------- |
| Earthquake       | EQ   | Red circle | USGS, EMSC        |
| Flood            | FL   | Wave       | Satellite imagery |
| Tropical Cyclone | TC   | Cyclone    | NOAA, JMA         |
| Volcano          | VO   | Volcano    | Smithsonian GVP   |
| Wildfire         | WF   | Fire       | MODIS, VIIRS      |
| Drought          | DR   | Sun        | Multiple sources  |

**Alert Levels**:

| Level      | Color    | Meaning                                  |
| ---------- | -------- | ---------------------------------------- |
| **Red**    | Critical | Significant humanitarian impact expected |
| **Orange** | Alert    | Moderate impact, monitoring required     |
| **Green**  | Advisory | Minor event, localized impact            |

## NASA EONET (Earth Observatory Natural Event Tracker)

Near-real-time natural event detection from satellite observation:

| Category      | Detection Method        | Typical Delay |
| ------------- | ----------------------- | ------------- |
| Severe Storms | GOES/Himawari imagery   | Minutes       |
| Wildfires     | MODIS thermal anomalies | 4-6 hours     |
| Volcanoes     | Thermal + SO2 emissions | Hours         |
| Floods        | SAR imagery + gauges    | Hours to days |
| Sea/Lake Ice  | Passive microwave       | Daily         |
| Dust/Haze     | Aerosol optical depth   | Hours         |

## Multi-Source Deduplication

When both GDACS and EONET report the same event:

1. Events within 100km and 48 hours are considered duplicates
2. GDACS severity takes precedence (human-verified)
3. EONET geometry provides more precise coordinates
4. Combined entry shows both source attributions

## Filtering Logic

To prevent map clutter, natural events are filtered:

* **Wildfires**: Only events \< 48 hours old (older fires are either contained or well-known)
* **Earthquakes**: M4.5+ globally, lower threshold for populated areas
* **Storms**: Only named storms or those with warnings