The open data landscape for disaster monitoring
One of the most remarkable developments in disaster monitoring over the past decade is the availability of real-time, machine-readable data feeds from authoritative government and international sources — completely free of charge. NASA, USGS, NOAA, GDACS, and other organizations publish API endpoints that anyone can integrate into applications without licensing fees, usage limits (within reason), or institutional affiliation requirements.
This guide covers the most useful free APIs for building disaster monitoring tools, based on practical experience building PlanetSentry. Each API has different strengths, data models, update frequencies, and quirks. Understanding these differences is essential for building reliable applications.
NASA EONET: the multi-hazard event backbone
The Earth Observatory Natural Event Tracker (EONET) API provides a curated feed of natural events categorized by type: wildfires, severe storms, volcanoes, floods, earthquakes, sea and lake ice, landslides, and others. Events include geographic coordinates, source references, temporal extent, and status (open or closed).
EONET is not an automated detection system — events are curated by NASA staff based on reports from authoritative sources. This curation means the data quality is high, but there is a latency between event occurrence and EONET listing that can range from hours to days. EONET is best used as a reliable backbone for known events rather than a real-time alerting trigger.
- Base URL: https://eonet.gsfc.nasa.gov/api/v3/events
- Format: JSON (GeoJSON-compatible geometry)
- Rate limits: reasonable use, no formal key required
- Update frequency: events are added and updated as information becomes available
- Key parameters: status (open/closed), category, days, source
USGS Earthquake Hazards API: real-time seismic data
The USGS Earthquake Hazards Program API provides real-time and historical earthquake data in GeoJSON format. It is the most comprehensive publicly available earthquake feed, covering global events down to very small magnitudes in well-instrumented regions.
The API supports flexible queries by time range, magnitude range, geographic bounds, and other parameters. Real-time feeds are updated every minute and include events from the past hour, day, week, and month at various magnitude thresholds. For applications that need the latest earthquake data with minimal latency, this is the primary source.
- Base URL: https://earthquake.usgs.gov/fdsnws/event/1/query
- Format: GeoJSON, CSV, XML, QuakeML
- Update frequency: every 1 minute for real-time feeds
- Key fields: magnitude, depth, location, time, felt reports, tsunami flag, alert level
- Detail endpoint: full event page with moment tensors, shakemaps, and DYFI data
GDACS: alert-level disaster assessment
The Global Disaster Alert and Coordination System provides alert-level assessments for earthquakes, floods, tropical cyclones, volcanic eruptions, droughts, and wildfires. Unlike raw event feeds, GDACS applies impact estimation models that consider population exposure and vulnerability to assign severity levels: Green (low humanitarian impact), Orange (moderate), and Red (high).
GDACS data is available through RSS/XML feeds and a GeoJSON API. The alert assessments are particularly valuable because they provide context that raw detection feeds lack — knowing that an earthquake occurred is less useful than knowing that it occurred near a densely populated area with vulnerable building stock.
NASA FIRMS: active fire detections
The Fire Information for Resource Management System provides near-real-time active fire detection data from MODIS and VIIRS satellite instruments. Data is available in multiple formats including CSV, shapefile, KML, and WMS/WFS services.
FIRMS offers both a global download and a map-based API that returns fire detections within a specified area and time range. Registration for a free MAP_KEY is required. The data includes fire coordinates, confidence level, fire radiative power, satellite identifier, and overpass time. For wildfire monitoring applications, FIRMS provides the highest-density point data available from any free source.
Additional valuable APIs
Beyond the core four, several other free APIs provide useful data for disaster monitoring applications. NOAA's National Hurricane Center publishes forecast advisory data and GIS shapefiles for active tropical cyclones. The Smithsonian Global Volcanism Program maintains a database of active volcanoes and recent eruptions. ReliefWeb's API provides humanitarian reports and situation updates for ongoing disasters.
For weather context, the Open-Meteo API provides free weather forecast and historical data. The NOAA Climate Data Online API offers long-term climate records. The European Copernicus Emergency Management Service provides activation maps for major disasters using satellite imagery analysis.
- NHC GIS data: https://www.nhc.noaa.gov/gis/ — active storm tracks, forecast cones, wind probabilities
- GVP: https://volcano.si.edu/ — volcano database, weekly reports
- ReliefWeb API: https://api.reliefweb.int/ — humanitarian reports and updates
- Open-Meteo: https://open-meteo.com/ — free weather forecast API, no key required
- Copernicus EMS: https://emergency.copernicus.eu/ — satellite-based damage assessment maps
Practical architecture advice
When building with multiple APIs, implement each as an isolated adapter that normalizes the source data into your internal model. This isolation means that when an API changes its format (and they do), you only need to update one adapter rather than touching your entire application.
Cache aggressively. Most of these APIs return data that changes at most every few minutes. There is no reason to hit them on every user request. Server-side caching with appropriate TTLs reduces your load on the APIs (being a good citizen) and dramatically improves your application's response time and reliability.
Building on PlanetSentry's open-source approach
PlanetSentry is built entirely on these free, open data sources. The codebase demonstrates practical patterns for integrating, normalizing, and displaying multi-source disaster data on an interactive globe. Developers interested in building similar tools can learn from the source structure: API routes for each data source, a shared event model, and presentation layers that work with the normalized data.
The open data ecosystem for disaster monitoring is deep enough to build sophisticated applications without any paid data subscriptions. The challenge is not data availability — it is integration quality, update reliability, and user experience. Those are engineering problems, not access problems.