Fig. 2.(a) The Parkfield recurrences1 represents the failure stress of the fault. Most characteristic earthquakes
occur at s1; the 1934 shock
occurred at s2. A constant loading
rate of 2.8 cm per year and a coseismic slip of 60 cm for the Parkfield
earthquake sequences in 1881, 1901,1922,1934, and 1966 are assumed (56).
(b) Series of earthquake sequences at Parkfield since 1850 [after (5)],
The line represents the linear regression of the time of the sequence
obtained without the 1934 sequence, The anticipated time of the seventh
(that is, the next) Parkfield sequence for the regression is January 1988.
(c) Shocks of ML greater than 4 since 1930 have tended
to occur when the stress exceeds s2 .
