All earthquake records come from the USGS Earthquake Hazards Program. We refresh the live feed every minute, keep five years of magnitude 2.5 and larger history, and compute local statistics as simple counts within 100 km of a city.

Sources

Earthquakes: USGS real-time GeoJSON feeds and the FDSN event web service. USGS data is in the public domain.
Places: GeoNames cities with population over 15,000, licensed CC BY 4.0.
Base map: OpenFreeMap tiles from OpenStreetMap data.

Update cadence

The past-day feed is fetched every minute and the past-week feed every hour. Events USGS later deletes are removed from our database. Magnitudes and locations of recent events are often revised in the first hours, and our pages show the latest USGS values.

Distances

Distance is the great-circle (haversine) distance in kilometres between the place’s coordinates and the earthquake epicentre, also shown in miles.

Local statistics

Counts on place pages include only earthquakes of magnitude 2.5 and above within 100 km, so that the 24-hour, 7-day, 30-day, 1-year and 5-year numbers are comparable.
The “1 year vs 5-year average” comparison divides the 5-year count by five.
Place pages are indexed by search engines only if the place had at least 100 such earthquakes in five years; quieter places remain reachable but are marked noindex.
Statistics are refreshed every six hours.

Regions and countries

For U.S. states, an earthquake belongs to the state USGS names at the end of its location (for example “…, Alaska” or “…, CA”). Everywhere else, and for country totals, each earthquake is counted once for the region of the nearest listed city within 300 km of its epicentre, and open-ocean earthquakes with no city in range are left out. Within one country counts use magnitude 2.5 and above. Countries are compared at magnitude 4.5 and above, the level at which the USGS catalogue is complete worldwide, because smaller earthquakes are detected much more thoroughly in some countries than others. All windows are the last five years.

Limits

Below about magnitude 2.5 the catalogue is complete only in the U.S. and a few other well-instrumented regions, so “no earthquakes” can mean “none detected”.
Counts describe past activity. They are not forecasts and not a hazard or risk assessment.
Event times are shown in UTC.

Questions or corrections: see contact.