Hypocenter 01
Hypocenter 01 : A point in the Earth (also called earthquake focus) where the rupture of the rocks initiates during an earthquake. Its position, in practice, is determined from arrival times of the seismic phase onsets recorded by seismographs.. The point on the Earth's surface vertically above the hypocenter is called the epicenter. See: Lee and Stewart (1981, p. 130-139)