Fig. 1: Activity of slow slip with tremors (SST) and in-slab earthquakes.
From: Effects of episodic slow slip on seismicity and stress near a subduction-zone megathrust
a Tremor (black dots) and slab seismicity (red dots) in Kii Peninsula. Thin black curves show depth contours of the Philippine Sea Plate4,5. Blue dashed lines outline regions with a slip-deficit rate greater than 1.5 cm/yr, indicating sites of expected future great megathrust earthquakes6. Red and green shaded areas show the tremorgenic zone and the region updip of it. b Tremor occurrence times versus distance along the strike of the subducting slab. Times of the major SSTs on different segments are shown by blue (region A, 38 times), red (region B, 37 times), and green (region C, 34 times) lines. The division of regions is shown in (a). The distance along the strike is measured from point C in (a). Gray circles indicate tremors. Solid blue circles and diamonds show upper-plane slab events with focal mechanisms, beneath the SST zone and the region of updip of it, respectively, that occurred in 2-month time windows before SST. Solid red circles and diamonds show upper-plane slab events with focal mechanisms, beneath the SST zone and the region updip of it, respectively, that occurred in 2-month time windows after SST. c Schematic cross-section of the area beneath Kii Peninsula.
