Fig. 12 Relationship between the seismic, transition, and creep zones in a subduction zone, and the processes associated with each.
These repeaters in a cluster are assumed to occur on the same small asperity surrounded by an aseismic creeping zone on the plate boundary.
Along the creeping zone of the San-Andreas fault, earthquakes have high b-values which may indicate a low stress (high pore pressure).
The creeping zone includes the white and yellow areas east of the Boso Peninsula in Figure 3, which lies east of Tokyo.
It has been pointed out that SREs are caused by the repeated rupture of small asperities within the creeping zone of a fault plane (e.g., Nadeau et al., 1995; Igarashi et al., 2003; Uchida et al., 2003).
As noted above, the creeping zone in Figure 3 includes the white and yellow areas east of the Boso Peninsula, supporting the prevailing view that it is incapable of generating large earthquakes.
For the 1964 Alaska, it seems that the creeping zone (Fig. 6), next to the PWS asperity (Fig. 3), prevented the rupture propagation from a strong initial break (Wyss and Brune, 1967; Ruff and Kanamori, 1983), which may result in a seismic directivity of long-period surface waves unoriented to that of its aftershock region (Kanamori, 1970).
Bourouis and Bernard ([2007]) observed in the data of seismicity induced during GPK1 stimulation repeated shear movements on fault asperities surrounded by creeping zones.
In recent years, 'repeating earthquakes' in the sense of waveform cross-correlation have been observed over a wide range of magnitudes and diverse tectonic environments such as creeping zones of major faults (Vidale et al., 1994; Rubin, 2002), interplate subduction zones (Igarashi, 2003; Uchida et al., 2010), and inland regions (Schaff and Richards, 2004b, 2011).
