Extended Data Fig. 4: Mainshock epicentral regions are active in the 30 minutes prior to mainshocks.
From: Stress-driven recurrence and precursory moment-rate surge in caldera collapse earthquakes
Epicenters of earthquakes in 26 of the last 29 collapse cycles. (26 depicted VLP locations are from Shelly and Thelen (2019). Three VLPs locations, in Cycles 34, 41, and 46, are not available in the Shelley-Thelen catalog.) Epicenters colored by time to collapse. Light blue: background time to failure > 30 minutes, dark blue: last 30 minutes; red stars mainshocks epicenters. Note that nearly all mainshocks are preceded by nearby VT events in the final 30 minutes, supporting the hypothesis that mainshocks are runaway VT earthquakes.
