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1 Institute of Geophysics, Victoria University of Wellington, New Zealand
2
Seismological Laboratory, California Institute of Technology, Pasadena, California,
USA
Geophysical Research Letters
Introduction
Martha K. Savage
1
, Fan-Chi Lin
2
, John Townend
1
Supplementary material includes four figures and a movie that supplement the article.
The underlying data were all processed as described in the main text.
Figure S1. Record sections of all nine cross-correlation functions of broadband data.
Earthquake-station pairs with propagation directions between 220 and 370 degrees were reversed, so that the positive lag times correspond to energy arriving from NNE through SSW. The gray lines on the ZZ and RR components denote a 1.1 km/s moveout speed. Each waveform is normalized relative to its own maximum amplitude.
18
Figure S2. Sensitivity of the phase velocity of Rayleigh waves calculated for the fundamental and first higher modes, using the velocity model in Table 1. Red solid line is for Vs, green dashed line for Vp and blue dashed line for density. Left: sensitivity of the fundamental mode. Right: sensitivity of the first higher mode. Top:
Phase velocity sensitivity. Bottom: Sensitivity of H/V ratio.

19 Figure S3. More detailed version of Figure 4. Absolute value of H/V ratios from
20 synthetic modeling (curve), and the observed distributions over all station pairs of the
21 maximum amplitude of the radial component divided by the maximum amplitude of
22 the vertical component for the given mode (see text for definition). Box and whiskers
23 plots are separated into those from the entire distribution (gray); from just the
24 westward-propagating paths (blue); and from the eastward-propagating paths (red).
25 Note that the same shape as a function of period is seen in all manifestations (a) 1st
26 order mode (b) fundamental mode. Note the change of scale for the period axis,
27 since the windows of the 1st order mode had smaller window lengths than that of the
28
29 Figure S4. SNR for the (a) fundamental (mode 0 for frequencies between 0.08 and
30 0.2 Hz) and (b) first higher mode (mode 1 for frequencies between 0.4 and 1 Hz). For
31 each station pair, two bars with opposite directions are plotted at each station. The
32 length of each bar is proportional to the SNR at positive or negative lag (whichever is
33 appropriate) multiplied by the square root of the inter-station distance (Lin et al.,
34 2007). The directions point along the great-circle linking the stations in the direction
35 toward which the energy propagates. For example, energy propagating from the south
36 will be represented by a northward pointing bar. Colors represent different
37 components: Yellow are RR, red is ZZ and blue is TT.
38
39 S5. Movie of the Rayleigh wave propagation for the velocity model in Table 1. Red
40 circles represent the synthetic particle motion due to a horizontal force at 0.75 km
41 depth calculated from the velocity model in Table 1. The particle motion is band

42 passed between 0.4-1 Hz.