episentrum

The episentrum (epicenter in English) is the point on the Earth's surface directly above the earthquake's hypocenter, the location within the crust where the rupture begins. The epicenter is a surface projection used to describe where shaking is centered on the map.

In English the standard term is epicenter; episentrum is used in several languages, including Dutch and Indonesian, as a direct translation. The concept is central to seismology, hazard assessment, and emergency response.

Determination: Epicenters are estimated from seismic data collected at multiple stations. By measuring the arrival times of P-waves and S-waves, scientists compute the distance from each station to the hypocenter. Using at least three stations, they triangulate the fault’s projection to the surface to determine the epicenter, and often estimate depth.

Shaking vs. epicenter: The epicenter is not necessarily where ground motion is strongest. Peak ground intensity depends on rupture size and mechanism, depth, distance, and local geology. Shaking can be maximum at sites away from the epicenter due to wave focusing and site effects.

Applications and limitations: The epicenter helps map affected areas, issue alerts, and guide aftershock studies. Location accuracy depends on station density and data quality; complex ruptures may yield uncertain epicenters.