Data sources and methods
Every figure on this site can be traced to a public scientific dataset. Here is where each one comes from and how we processed it.
Plate outlines and boundaries
Bird, P. (2003), An updated digital model of plate boundaries, Geochemistry, Geophysics, Geosystems, 4(3), 1027. We use the GeoJSON conversion by Hugo Ahlenius (github.com/fraxen/tectonicplates, Open Data Commons Attribution License). The model has 52 plates and 260,794 km of boundaries split into about 5,800 short steps, each classified as a subduction zone, oceanic or continental convergent boundary, spreading ridge, continental rift, or oceanic or continental transform fault, with the relative velocity of the two plates.
- Plate area is computed on the sphere from the plate polygons. All 52 add up to Earth's surface area within 0.01%.
- Boundary type for a pair of plates is the type that covers the greatest length of their shared boundary.
- Plate speeds are relative speeds between neighboring plates along their boundary, averaged by length. They are not speeds relative to a fixed point on Earth.
Countries
Country and territory outlines are from Natural Earth (1:50 million, public domain). We intersect each of the 213 outlines with each plate to measure what share of its land lies on which plate. Small islands and coastlines are simplified, so tiny shares (under 0.1%) are shown as "less than 0.1%".
Satellite imagery
The imagery behind every interactive map is NASA's Blue Marble Next Generation with topography and bathymetry (July 2004 composite, NASA Earth Observatory, Reto Stöckli). It is a cloud-free mosaic of MODIS satellite images with the shape of the sea floor shaded in, which is why mid-ocean ridges and deep trenches show up next to the plate boundaries. We cut it into map tiles ourselves and serve them from this site.
Earthquakes
Historic earthquakes are all magnitude 6.5 and larger events since 1900 in the USGS ComCat catalog. Each event is assigned to the plate that contains its epicenter, and to a country if the epicenter falls inside the country or the USGS place name refers to it (which captures offshore quakes). The live earthquake map reads the USGS real-time GeoJSON summary feeds.
Volcanoes
Global Volcanism Program (Smithsonian Institution), Volcanoes of the World, Holocene volcano list (1,214 volcanoes). Last eruption dates are as listed there. Volcanoes are assigned to plates by location.
Tropical cyclones
Active storms: GDACS, the Global Disaster Alert and Coordination System (European Commission Joint Research Centre and UN OCHA), which compiles advisories from the US National Hurricane Center, the Joint Typhoon Warning Center and others. Past seasons: NOAA National Hurricane Center HURDAT2 best-track data for the Atlantic and northeast Pacific basins.
Aurora
NOAA Space Weather Prediction Center: OVATION aurora 30-minute forecast, planetary K-index (1-minute estimate) and 3-day Kp forecast.
Updates
Plate geometry and country outlines change rarely. Historic earthquake and volcano statistics are rebuilt periodically. Live maps always use the latest available feed.