What is the difference between epicenter, hypocenter & fault rupture?
When an earthquake is felt or detected by a seismograph, there was always a patch on some fault that broke and experienced an offset, to cause the seismic waves. If the quake was small, the area of the patch was small & the waves generated were weak. If the quake was large, a large area of fault broke, and so forth. This area of breakage is called the fault rupture. The fault rupture does not all break at once, however. It generally starts at one place and propagates along the fault. The place where the rupture starts is the place that generates the first P and S waves, which are measured by the P picker and used to locate the earthquake, even though it may not represent the whole rupture at all. It is called the hypocenter. The epicenter is the place on the map directly above the hypocenter. Note that, for a very large earthquake with a large fault rupture, many areas damaged due to being near the fault rupture, may actually be quite far from the epicenter. Also, if the fault dips, or
