01 / What makes the Earth move?
Tectonic plates move slowly. When a locked fault slips suddenly, stored energy travels through the Earth as seismic waves. These waves cause the shaking we call an earthquake. Many events occur near plate boundaries, but earthquakes can also happen inside plates.
02 / Reading earthquake magnitude
Magnitude describes an earthquake’s size from seismic measurements. It is different from intensity: the shaking experienced at a particular location. The same earthquake can produce different intensities depending on distance, ground conditions and buildings. A magnitude number alone does not describe local damage.
03 / Epicenter, focus and depth
The focus, or hypocenter, is the place underground where rupture begins. The epicenter is the point on the surface directly above it. Depth indicates how far below the surface the event began. Shaking depends on depth as well as magnitude, distance and local geology.
04 / Aftershocks and tremors
Aftershocks are earthquakes that follow a larger event in the same general area as the crust readjusts. Sequences can continue for a long time. The tracker shows reported events; proximity alone does not prove that two earthquakes belong to the same sequence. “Tremor” is often used informally for light shaking.
05 / Why the world map looks uneven
Earthquakes cluster around active tectonic boundaries, including the Pacific Ring of Fire. Monitoring networks and reporting thresholds differ between regions. A quiet area on this map does not mean there is no earthquake hazard, and a busy period does not predict a larger event.
06 / A tracker, a forecast and a warning
An earthquake tracker displays detected events. A forecast estimates probabilities. An official early warning system detects an earthquake after it starts and may notify some locations before strong shaking arrives. None of these is a precise prediction of a future earthquake. Use local official services for safety decisions.