hypocentral
adj- It moved through the hypocentral region of the most recent magnitude 6 Parkfield earthquakes, triggering a succession of increasingly energetic episodes of slip-induced seismicity, and culminated with near complete relaxation in that region.1999 July 30, Robert M. Nadeau, Thomas V. McEvilly, “Fault Slip Rates at Depth from Recurrence Intervals of Repeating Microearthquakes”, in Science, volume 285, number 5428, →DOI, pages 718–721: