Fig. 8
From: Migration of earthquakes with a small stress drop in the Tanzawa Mountains, Japan
Estimated stress drops from (a) P and (b) S waves as a function of time. The horizontal broken line indicates the average stress drop of earthquakes that occurred before the cluster activity. Results after January 2012, which are shaded by the gray color in (a) and (b), are also shown in (c) and (d). Two earthquakes after the cluster activity had values of stress drop similar to those of earthquakes before the cluster activity