Risk explorer
Pick a point and check the earthquakes recorded around it since 1976 (USGS) and what its climate has been like over the last 20 years (NASA POWER): extreme heat, tropical nights, heavy rain and dry spells.
Exposure, not risk or prediction
It shows earthquakes already recorded and observed climate. It isn't an official hazard map, doesn't predict earthquakes or project future climate, and doesn't assess a building's vulnerability. For construction or insurance decisions, check the regulations and consult a professional.
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Calculation version: georisk-seismic@1.0.0 and georisk-climate@1.0.0. Cartography: Natural Earth.
How to use it
- 1Mark a point on the map or type its latitude and longitude, and choose the radius to search for earthquakes (50 to 300 km).
- 2Press “Check earthquakes and climate”. The first query for a point takes longer; after that it's cached.
- 3Check the recorded earthquakes by magnitude, the strongest and the nearest of magnitude 6 or more, and the climate indicators year by year.
- 4For floods in Spain, open the official SNCZI viewer linked at the end.
How it calculates
- Earthquakes: USGS ComCat catalogue, magnitude 4.5 or above since 1 January 1976, at a straight-line distance (haversine) smaller than the radius. Observed frequency = earthquakes / years in the period.
- Climate: NASA POWER daily data (MERRA-2 reanalysis) for the last 20 complete calendar years. Years with fewer than 90% of days with data are discarded.
- Extreme heat days: maximum ≥ 35 °C. Tropical nights: minimum ≥ 20 °C. Heavy rain: ≥ 20 mm in the day (R20mm). Dry spell: maximum number of consecutive days with less than 1 mm (CDD).
- “Between halves” = average of the last 10 years − average of the first 10. It's descriptive: not a statistical trend or a projection.
Verifiable example
With real USGS data: for a point in central Los Angeles (34.0537, −118.2427) and a 100 km radius, the Northridge earthquake of 17 January 1994 (magnitude 6.7) appears about 32 km away, in the 6.0 to 6.9 band. If 25 earthquakes of magnitude 4.5 or more are recorded within the radius over 50 years, the observed frequency is 0.5 per year, which doesn't mean there's a 50% chance of one next year.
Limitations
- Recorded seismicity isn't a hazard map or a probability: areas quiet for 50 years can have strong earthquakes with long return periods.
- The global catalogue is reasonably complete for magnitude 4.5 or above; smaller earthquakes, which can also cause local damage, aren't included.
- The climate comes from a reanalysis with cells of about 50 km: it doesn't capture urban effects, exact altitude or sea breezes at local scale.
- No flood, wildfire, landslide or climate change projection data is included.