Supplemental Table 3. CS2:

Calculating cummulative coseismic slip along the San Andreas Fault (SAF) for the 6 accepted Parkfield earthquakes as in CS1 + coseismic slip from 3 additional Toppozada et al., 2002 identified events (1877, 1908, and 1922)

Toké N.A. and J R. Arrowsmith Reassessment of a slip budget along the Parkfield segment of the San Andreas Fault.


Explanation of assumptions:

For 2004, 1934, 1922, 1901, and 1881 the coseismic slip is assumed to be the surface slip presented in Lienkaemper et al., BSSA this issue.

For 1966 the coseismic slip is assumed to be the surface slip as presented in Lienkaemper and Prescott, 1989.

For 1877, 1908, and 1922b the rupture extent and average slip were calculated using the empirical relationships of Wells and Coppersmith, 1994 (modified by Arrowsmith et al., 1997 for California strike-slip earthquakes). Empirical calculations are shown after the table of coseismic slip.

Table:

distance NW of Highway 46 (km) key locations along the SAF 1877 slip (cm) 1908 slip (cm) 1922b slip (cm) 1881 slip (cm) 1901 slip (cm) 1922 slip (cm) 1934 slip (cm) 1966 slip (cm) 2004 slip (cm) cumulative coseismic slip since 1857 (m)
-25 0
-24 0
-23 0
-22 0
-21 0
-20 0
-19 0
-18 0
-17 0
-16 0
-15 0
-14 0
-13 0
-12 0
-11 0
-10 0
-9 0
-8 0
-7 1 0.01
-6 2 0.02
-5 1 1 1 1 4 1 0.09
-4 2 2 2 2 6 2 0.16
-3 3 3 3 3 8 3 0.23
-2 4 4 4 4 10 4 0.30
-1 5 5 5 5 12 5 0.37
0 CA Highway 46 6 6 6 6 13 6 0.43
1 6 6 6 6 13 6 0.43
2 7 7 7 7 14 7 0.49
3 7 7 7 7 15 7 0.50
4 7 7 7 7 16 7 0.51
5 8 8 8 8 17 8 0.57
6 8 8 8 8 18 8 0.58
7 9 9 9 9 19 9 0.64
8 9 9 9 9 20 9 0.65
9 10 10 10 10 20 10 0.70
10 10 10 10 10 21 10 0.71
11 15 15 15 15 27 15 1.02
12 21 21 21 21 33 21 1.38
13 27 27 27 27 39 27 1.74
14 32 32 32 32 46 32 2.06
15 32 32 32 32 45 32 2.05
16 31 31 31 31 44 31 1.99
17 31 31 31 31 43 31 1.98
18 30 30 30 30 42 30 1.92
19 21 30 30 30 30 41 30 2.12
20 21 29 29 29 29 40 29 2.06
21 Carr Hill 21 29 29 29 29 39 29 2.05
22 Parkfield 28 28 28 28 38 28 1.78
23 27 27 27 27 37 27 1.72
24 26 26 26 26 35 26 1.65
25 25 25 25 25 33 25 1.58
26 23 23 23 23 31 23 1.46
27 22 22 22 22 29 22 1.39
28 20 20 20 20 27 20 1.27
29 19 19 19 19 26 19 1.21
30 17 17 17 17 24 17 1.09
31 16 16 16 16 23 16 1.03
32 15 15 15 15 22 15 0.97
33 14 14 14 14 21 14 0.91
34 13 13 13 13 20 13 0.85
35 30 12 12 12 12 19 12 1.09
36 30 11 11 11 11 18 11 1.03
37 30 10 10 10 10 17 10 0.97
38 30 9 9 9 9 16 9 0.91
39 30 8 8 8 8 15 8 0.85
40 30 7 7 7 7 14 7 0.79
41 30 6 6 6 6 13 6 0.73
42 5 5 5 5 12 5 0.37
43 4 4 4 4 11 4 0.31
44 3 3 3 3 10 3 0.25
45 2 2 2 2 9 2 0.19
46 26 1 1 1 1 8 1 0.39
47 26 7 0.33
48 Slack Canyon 26 6 0.32
49 26 5 0.31
50 26 4 0.30
51 26 3 0.29
52 2 0.02
53 1 0.01
54 0
55 0
56 0
57 0
58 0
59 0
60 0

Empirical Calculations

Relationship between magnitude and rupture area (Arrowsmith et al., 1997)
Moment Magnitude = 3.9987 + 0.97471 log (rupture area (km2))

We assume a constant rupture depth of 10 km

Toppozada Identified events (date, estimated magnitudes, and location)
date Magnitude (Mw) Location NW of Highway 46
5/30/1877 5.5 20.1
4/27/1908 5.8 37.9
8/18/1922 5.7 49.3


Rupture area Calculations = 10((Mw-3.9987)/0.97471)
date Rupture area (km2)
5/30/1877 34.7
4/27/1908 70.5
8/18/1922 55.6


Rupture Length = Rupture area/10km
date Rupture length (km)
5/30/1877 3
4/27/1908 7
8/18/1922 6


Moment = Mo=10((3/2)*(Mw+10.73))
date moment (dyn/cm)
5/30/1877 2.21309E+24
4/27/1908 6.23735E+24
8/18/1922 4.4157E+24


Displacement = [Mo/(u = 3*1011 dyn/cm)*(rupture area (cm2))]
date displacement (cm)
5/30/1877 21
4/27/1908 30
8/18/1922 26

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