This electronic supplement consists of three sections:
You may download supplemental files here; they are also linked in the text below.
Here we provide additional figures to aid in visualizing the nonplanar model fault geometry used in the inversions and its spatial relationship to the aftershocks of the September 28, 2004 M6 Parkfield earthquake.
Figure S1a: Enlarged, color version of Figure 4 showing the model fault geometry looking from two angles. Red lines are intersection of the model geometry with the Earth's surface and coincide with the main mapped trace of the SAF on the northeast, and the mapped trace of the SWFZ on the southwest. Light blue shaded portion is the subsidiary fault surface which intersects the mapped SWFZ at the Earth's surface. Star is hypocenter of the Parkfield 2004 M6 earthquake.
Figure S1 b - g: Depth sections showing model fault at the specified depth (green line) in a local Cartesian coordinate system with its origin at Carr Hill. Aftershocks of the 2004 M6 event (blue dots, Thurber et al., this issue) located from 1 km below to 1 km above the specified depth are projected onto a horizontal plane at the specified depth for plotting. Red line is the intersection of the model fault geometry with the Earth's surface. Specified depths for each figure are b) 2 km, c) 4 km, d) 6 km, e) 8 km, f) 10 km, g) 12 km.
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Table S1 presents the observed data, standard errors, predicted data, and residuals for the inversions.
Figures S2 - S4 are maps of the observed and predicted GPS displacements for the following time periods:
Figure S2:Observed (black vectors with 95% confidence ellipses) and predicted (white vectors) displacements of GPS sites in the Parkfield area during the coseismic plus first 60 days of the postseismic period. Brown lines are mapped faults. Black line is intersection of the model fault geometry with the Earth's surface. Grey dashed lines are major highways, labeled with their route numbers. Star is the epicenter of the September 28, 2004 M6 Parkfield earthquake. Some station names have been omitted for figure clarity.
Figure S3:Observed (black vectors with 95% confidence ellipses) and predicted (white vectors) displacements of GPS sites in the Parkfield area during the coseismic plus first 230 days of the postseismic period. Brown lines are mapped faults. Black line is intersection of the model fault geometry with the Earth's surface. Grey dashed lines are major highways, labeled with their route numbers. Star is the epicenter of the September 28, 2004 M6 Parkfield earthquake. Some station names have been omitted for figure clarity.
Figure S4:Observed (black vectors with 95% confidence ellipses) and predicted (white vectors) displacements of GPS sites in the Parkfield area from days 60 to 230 of the postseismic period. Brown lines are mapped faults. Black line is intersection of the model fault geometry with the Earth's surface. Grey dashed lines are major highways, labeled with their route numbers. Star is the epicenter of the September 28, 2004 M6 Parkfield earthquake. Some station names have been omitted for figure clarity.
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Here we present plots that depict the resolving power of the interseismic data for slip on the San Andreas fault beneath Middle Mountain.
Figure S5: Each plot shows the model resolution for the subfault indicated by the star. If model resolution were perfect, the amplitude of the resolution would be one on that subfault and zero everywhere else.
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