Supplemental Table 4. CS3:

Calculating cummulative coseismic slip along the San Andreas Fault (SAF) near Parkfield

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 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 events prior to 1966 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 coseismic slip table.

Table:

distance NW of Highway 46 (km) key locations along the SAF 1877 slip (cm) 1881 slip (cm) 1901 slip (cm) 1908 slip (cm) 1922 slip (cm) 1922b 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 4 1 0.05
-4 6 2 0.08
-3 8 3 0.11
-2 10 4 0.14
-1 12 5 0.17
0 CA Highway 46 13 6 0.19
1 13 6 0.19
2 14 7 0.21
3 15 7 0.22
4 16 7 0.23
5 17 8 0.25
6 18 8 0.26
7 19 9 0.28
8 20 9 0.29
9 20 10 0.30
10 21 10 0.31
11 27 15 0.42
12 33 21 0.54
13 39 27 0.66
14 46 32 0.78
15 45 32 0.77
16 44 31 0.75
17 43 31 0.74
18 42 30 0.72
19 21 41 30 0.92
20 21 40 29 0.90
21 Carr Hill 21 39 29 0.89
22 Parkfield 38 28 0.66
23 37 27 0.64
24 35 26 0.61
25 33 25 0.58
26 37 31 23 0.91
27 37 29 22 0.88
28 37 27 20 0.84
29 37 26 19 0.82
30 37 24 17 0.78
31 37 23 16 0.76
32 37 22 15 0.74
33 37 21 14 0.72
34 37 20 13 0.70
35 30 37 19 12 0.98
36 30 37 18 11 0.96
37 30 17 10 0.57
38 37 30 16 9 0.92
39 37 30 51 15 8 1.41
40 37 30 51 14 7 1.39
41 37 30 51 13 6 1.37
42 37 51 12 5 1.05
43 37 51 11 4 1.03
44 37 51 10 3 1.01
45 37 51 9 2 0.99
46 37 51 26 8 1 1.23
47 37 51 26 7 1.21
48 Slack Canyon 37 51 26 6 1.20
49 51 26 5 0.82
50 57 51 26 4 1.38
51 57 51 26 3 1.37
52 57 51 2 1.10
53 57 51 1 1.09
54 57 51 1.08
55 57 51 1.08
56 57 51 1.08
57 57 51 1.08
58 57 51 1.08
59 57 51 1.08
60 57 51 1.08

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
2/2/1881 6.0 42.8
3/3/1901 6.4 63.6
4/27/1908 5.8 37.9
3/10/1922 5.8 49.3
8/18/1922 5.7 49.3
1/8/1934 6.0 30.8


Rupture area Calculations = 10((Mw-3.9987)/0.97471)
date Rupture area (km2)
5/30/1877 35
2/2/1881 113
3/3/1901 291
4/27/1908 70
3/10/1922 230
8/18/1922 56
1/8/1934 113


Rupture Length = Rupture area/10km
date Rupture length (km)
5/30/1877 3
2/2/1881 11
3/3/1901 29
4/27/1908 7
3/10/1922 23
8/18/1922 6
1/8/1934 11


Moment = Mo=10((3/2)*(Mw+10.73))
date moment (dyn/cm)
5/30/1877 2.21E+24
2/2/1881 1.24E+25
3/3/1901 4.95E+25
4/27/1908 6.24E+24
3/10/1922 3.51E+25
8/18/1922 4.42E+24
1/8/1934 1.24E+25


Displacement = [Mo/(u = 3*1011 dyn/cm)*(rupture area (cm2))]
date displacement (cm)
5/30/1877 21
2/2/1881 37
3/3/1901 57
4/27/1908 30
3/10/1922 51
8/18/1922 26
1/8/1934 37

Valid HTML 4.0 Transitional