Supplementary Materials for

Daniel A Frost, Barbara Romanowicz

Correspondence to: dafrost@berkeley.edu

Contents of this file

Figures S1 to S14Tables S1 to S3

Introduction

The supporting information contains additional information about the data and method (Figures S1 and S3, and Table S1), observations of lower qualities that those shown in the main paper (Figures S2, and S4-S7), and the results of additional tests (Figures S8, and S9, and Tables S2 and S3). All measurements shown in the paper are listed in table S4 (available separately).

Supplementary Figures

Supplementary Figure 1. Relation beween the angles ξ1 and ξ2 of the two legs of the inner core P′ path with respect to the rotation axis for the Eilson (blue) and Yellowknife (red) arrays. All data are shown, both with and without clear P′P′ arrivals.

Supplementary Figure 2. Beams and array processing of a M7.1 event which occurred on 17/03/2003 at a depth of 33 km, recorded at YK, identified as poor quality (Supplementary Table 1). (a) Beams and F-traces formed on P′P′ab and P′P′df slownesses and back-azimuths. F-vespagrams formed for a range of (b) back-azimuths and (c) slownesses. Predicted times and slownesses from ak135 are shown by green triangles and lines. Observations are marked by blue lines representing onset times and circles showing the maximum F-amplitude, accounting for the time separation between the picks and peaks.

Supplementary Figure 3. Beams and array processing of a M6.7 event which occurred on 05/12/2003 at a depth of 10 km, recorded at IL, identified as poor quality (Supplementary Table 1).

Supplementary Figure 4. Beams and array processing of a M6.3 event which occurred on 06/03/2005 at a depth of 10 km, recorded at YK, identified as good quality (Supplementary Table 1).

Supplementary Figure 5. Beams and array processing of a M6.4 event which occurred on 08/10/2010 at a depth of 19 km, recorded at IL, identified as good quality (Supplementary Table 1).

Supplementary Figure 6. Beams and array processing of a M6.5 event which occurred on 12/03/2011 at a depth of 20 km, recorded at IL, identified as poor quality (Supplementary Table 1).

Supplementary Figure 7. Residual travel times as a function of average angle to the rotation axis for (a) ab-df differential measurements, (b) bc-df differential measurements, and (c) df absolute measurements. Individual measurements are shown by points, while moving averages (calculated in 3° bins with no overlap, calculated only for bins containing a minimum of 2 observations) are shown by purple circles with one standard deviation error bars. Residual travel times plotted along the inner core path (line color), for only the most polar of the source- and receiver-side paths (angle to pole shown by circle color), for (d) ab-df differential measurements, (e) bc-df differential measurements, and (f) df absolute measurements. Data shown have SNR greater than 1.

Supplementary Figure 8. Regions of possible scattering of P′P′ at the surface. Scattering from each location would generate waves with a characteristic (a) travel time shown relative to direct P′P′, (b) back-azimuth, and (c) slowness. The slowness and back-azimuth of scattering from other locations are distinct from reflection from the mid-point (circle) between the source (star) and array (triangle). Dashed and solid lines denote the path of the main phase and an example scattered path, respectively.

Supplementary Figure 9. Observed velocity anomalies from ab-df and bc-df differential residual travel times, as a function of average angle to the rotation axis, with corrections applied for tomographic velocities in (a) and (b) SEMUCB-WM1 scaled to P-waves, (c) and (d) S40RTS scaled to P-waves, (e) and (f) MIT_P08, (g) and (h) GAP_P4. Symbols as in Figure 4.

Supplementary Figure 10. Observed velocity anomalies from ab-df and bc-df differential residual travel times, and df absolute residual travel times, as a function of average angle to the rotation axis, with corrections applied for tomographic

velocities in (a) and (b) SEMUCB-WM1 scaled to P-waves, (c) and (d) S40RTS scaled to P-waves, (e) and (f) MIT_P08, (g) and (h) GAP_P4. Symbols as in Figure 4.

Supplementary Figure 11. Observed velocity anomalies from ab-df and bc-df differential residual travel times, as a function of average angle to the rotation axis, with events reflecting under the South Sandwich Islands removed. (a) Raw measurements for all observations are displayed as crosses and triangles for ab-df and bc-df, respectively, for df signals with SNR greater than 2. (b) Moving averages of observed velocity anomalies (purple) with one standard deviation error bars, and predicted velocity anomalies calculated from several anisotropy models for the observed events. Moving averages are calculated in 3° bins with no overlap, calculated only for bins containing a minimum of 2 observations.

Supplementary Figure 12. Observed velocity anomalies from ab-df and bc-df differential residual travel times, and df absolute differential travel times, as a function of average angle to the rotation axis. (a) Raw measurements for all observations. Velocity anomalies from paths reflecting under the South Sandwich Islands source region are shown in red. (b) Moving averages of observed velocity

anomalies (purple) with one standard deviation error bars, and predicted velocity anomalies calculated from several anisotropy models for the observed events. Moving averages are calculated in 3° bins with no overlap, calculated only for bins containing a minimum of 2 observations.

Supplementary Figure 13. Grid search over eastern and western hemisphere anisotropy. (a) Anisotropy curve (from Irving and Deuss [2011]) that is scaled to

model data. Root mean square misfit for east and west hemisphere anisotropy for: (b) all data with ab-df, bc-df, and absolute df observations, (c) excluding data reflecting under the South Sandwich Islands with ab-df, bc-df, and absolute df observations, (d) all data with only ab-df and bc-df observations, and (e) excluding data reflecting under the South Sandwich Islands with only ab-df and bc-df observations. Star shows minimum misfit with best-fitting anisotropy magnitudes shown above figure. Tested grid points shown in background.

Supplementary Figure 14. Curves to fit velocity anomalies as a function of average angle made with the polar axis, with bootstrap resampling. (a) Original data (circles) fit by a curve of equation 2 (green line). Bootstrap samples (grey) are summarized as a mean line (purple) and one standard deviation range (purple shading).

Coefficients of the line a, b, and c are shown above the figure. Curves to fit data corrected for travel time anomalies in tomographic models (b) SEMUCB-WM1 scaled to P-waves, (c) S40RTS scaled to P-waves, (d) MIT_P08, and (e) GAP_P4.

Supplementary Table 1. Details of events used. Events with discernable phases are classified as either good or poor, while events without phases are left blank.Year

Month

Day

Origin Time

Ev lat

Ev lon Depth (km)

mb Array

Ar lat Ar lon Major arc distance (deg)

P`P`df

P`P`bc

P`P`ab

2001

8 2 23:41:06.17

56.26

163.79 14 6.3 IL 64.77 -146.89

335.0

2001

10 8 18:14:26.44

52.59

160.32 48 6.5 IL 64.77 -146.89

331.0

2002

4 18

05:02:46.19

16.99

-100.86

24 6.8 IL 64.77 -146.89

303.2

2002

5 25

05:36:31.97

53.81

-161.12

33 6.4 IL 64.77 -146.89

346.9 GOOD

NONE

GOOD

2002

8 20

10:59:32.02

30.99

141.97 9 6.3 IL 64.77 -146.89

305.6

2002

10 3 16:08:29.62

23.32

-108.53

10 6.5 IL 64.77 -146.89

311.7

2002

10 19

12:09:05.38

44.3 149.96 33 6.3 IL 64.77 -146.89

320.2

2002

10 23

11:27:19.43

63.51

-147.91

4 6.7 IL 64.77 -146.89

358.7 GOOD

NONE

NONE

2002

11 3 03:37:42.07

38.89

141.98 39 6.4 IL 64.7714

-146.89

312.4

2002

11 3 22:12:41 63.52

-147.44

4 7.9 IL 64.77 -146.89

358.7 POOR

NONE

NONE

2002

11 7 15:14:06.76

51.2 179.33 33 6.6 IL 64.77 -146.89

337.9

2002

11 17

04:53:53.54

47.82

146.21 459

7.3 IL 64.7714

-146.89

321.4

2003

1 16

00:53:15.72

44.28

-129.02

10 6.3 IL 64.77 -146.89

337.2

2003

1 22

02:06:34.61

18.77

-104.1 24 7.6 IL 64.77 -146.89

305.9

2003

2 19

03:32:36.36

53.65

-164.64

19 6.6 IL 64.77 -146.89

345.7

2003

3 12

23:41:32.92

26.56

-110.59

10 6.4 IL 64.7714

-146.89

315.3

2003

3 17

16:36:17.31

51.27

177.98 33 7.1 IL 64.77 -146.89

337.4

2003

5 26

09:24:33.40

38.85

141.57 68 7.0 IL 64.77 -146.89

312.2 GOOD

DIFF GOOD

2003

6 15

19:24:33.15

51.55

176.92 20 6.5 IL 64.77 -146.89

337.2 POOR

NONE

POOR

2003

6 16

22:08:02.14

55.49

160 174

6.9 IL 64.77 -146.89

332.8 POOR

NONE

POOR

2003

6 23

12:12:34.47

51.44

176.78 20 6.9 IL 64.77 -146.89

337.1

2003

9 27

11:33:25.08

50.04

87.81 16 7.3 IL 64.77 -146.89

302.2 GOOD

GOOD

POOR

2003

9 27

11:50:56.67

49.96

88.1 0 6.0 IL 64.77 -146.89

302.2

2003

9 27

18:52:46.98

50.09

87.76 10 6.4 IL 64.77 -146.89

302.2 GOOD

GOOD

POOR

2003

9 29

02:36:53.14

42.45

144.38 25 6.5 IL 64.77 -146.89

316.3 POOR

DIFF POOR

2003

9 29

21:33:16.74

41.45

143.98 0 6.0 IL 64.77 -146.89

315.3

2003

10 1 01:03:25.24

50.21

87.72 10 6.7 IL 64.77 -146.89

302.3 GOOD

GOOD

POOR

2003

10 8 09:07:0.44

42.61

144.5 68 6.5 IL 64.77 -146.89

316.5 GOOD

DIFF GOOD

2003

10 31

01:06:28.28

37.81

142.62 10 7.0 IL 64.77 -146.89

311.7 POOR

DIFF POOR

2003

11 17

06:43:06.80

51.15

178.65 33 7.8 IL 64.7714

-146.89

337.6

2003

12 5 21:26:09.48

55.54

165.78 10 6.7 IL 64.77 -146.89

335.3 POOR

DIFF POOR

2004

5 29

20:56:09.60

34.25

141.41 16 6.5 IL 64.77 -146.89

308.2

2004

6 10

15:19:57.75

55.68

160 188

6.9 IL 64.77 -146.89

333.0 POOR

DIFF GOOD

2004

6 28

09:49:47 54.8 -134.25

20 6.8 IL 64.77 -146.89

348.2

2004

7 19

08:01:49.46

49.62

-126.97

23 6.4 IL 64.77 -146.89

341.5

2004

9 5 10:07:07.82

33.07

136.62 14 7.2 IL 64.77 -146.89

305.1 POOR

POOR

GOOD

2004

9 5 14:57:18.61

33.18

137.07 10 7.4 IL 64.77 -146.89

305.4 POOR

NONE

POOR

2004

9 6 23:29:35.09

33.21

137.23 10 6.6 IL 64.77 -146.89

305.5 GOOD

GOOD

POOR

2004

9 8 14:58:25.83

33.14

137.2 21 6.1 IL 64.77 -146.89

305.4 GOOD

POOR

POOR

2004

10 23

08:55:57.84

37.28

138.74 0 6.4 IL 64.77 -146.89

309.6 GOOD

GOOD

POOR

2004

11 2 10:02:12.82

49.28

-128.77

10 6.7 IL 64.77 -146.89

341.8

2004

12 6 14:15:11.89

42.9 145.23 35 6.8 IL 64.77 -146.89

317.1 POOR

DIFF POOR

2004

12 18

06:46:19.87

48.84

156.31 11 6.2 IL 64.77 -146.89

326.5

2005

3 6 05:21:43.43

84.95

99.39 10 6.3 IL 64.77 -146.89

332.3

2005

6 14

17:10:12.28

51.24

179.31 17 6.8 IL 64.77 -146.89

337.9 GOOD

DIFF GOOD

2005

6 15

02:50:54.19

41.29

-125.95

16 7.2 IL 64.77 -146.89

333.6

2005

6 27

11:35:45.60

18.78

-107.3 20 6.2 IL 64.77 -146.89

307.0

2005

8 16

02:46:28.40

38.28

142.04 36 7.2 IL 64.77 -146.89

311.9 POOR

DIFF GOOD

2005

10 19

11:44:42.79

36.4 140.84 32 6.3 IL 64.77 -146.89

309.8 POOR

POOR

POOR

2005

11 14

21:38:51.42

38.11

144.9 11 7.0 IL 64.77 -146.89

313.0 GOOD

DIFF POOR

2005

12 2 13:13:09.52

38.09

142.12 29 6.5 IL 64.77 -146.89

311.7 POOR

DIFF POOR

2006

1 4 08:32:32.40

28.16

-112.12

14 6.6 IL 64.77 -146.89

317.3

2006

4 20

23:24:58.39

60.93

167.02 0 7.5 IL 64.77 -146.89

339.0 GOOD

DIFF GOOD

2006

4 20

23:28:03.90

60.87

167.01 10 6.1 IL 64.7714

-146.89

339.0

2006

4 29

16:58:06.32

60.49

167.52 11 6.6 IL 64.77 -146.89

339.0

2006

5 10

02:42:51.03

52.51

-169.26

18 6.4 IL 64.77 -146.89

343.2

2006

5 22

11:11:57.47

60.79

165.71 0 6.7 IL 64.77 -146.89

338.4 POOR

NONE

POOR

2008

7 19

02:39:28.70

37.55

142.21 22 7.0 IL 64.77 -146.89

311.3 GOOD

DIFF GOOD

200 7 2 15:26:19. 39.8 141.46 10 6.8 IL 64.77 - 312.9

8 3 95 8 146.892008

8 27

01:35:32.15

51.61

104.16 16 6.3 IL 64.77 -146.89

308.4 GOOD

GOOD

POOR

2008

9 11

00:20:50.92

41.89

143.75 25 6.8 IL 64.77 -146.89

315.6 POOR

DIFF GOOD

2008

9 24

02:33:05.56

17.61

-105.5 12 6.4 IL 64.77 -146.89

305.3

2008

12 20

10:29:23.10

36.54

142.43 19 6.3 IL 64.77 -146.89

310.6 POOR

POOR

POOR

2009

1 15

17:49:39.07

46.86

155.15 36 7.4 IL 64.77 -146.89

324.5 GOOD

DIFF POOR

2009

3 6 10:50:29.41

80.32

-1.85 9 6.5 IL 64.77 -146.89

326.3 GOOD

DIFF GOOD

2009

4 7 04:23:33.15

46.05

151.55 31 6.9 IL 64.7714

-146.89

322.3

2009

4 18

19:18:0.11

46.04

151.46 42 6.4 IL 64.77 -146.89

322.2 POOR

DIFF POOR

2009

6 5 03:30:33.06

41.82

143.45 29 6.4 IL 64.77 -146.89

315.4 POOR

DIFF POOR

2009

8 3 17:59:56.17

29.04

-112.9 10 6.9 IL 64.77 -146.89

318.4

2009

8 3 18:40:50.10

29.31

-113.73

10 6.2 IL 64.77 -146.89

318.9

2009

8 9 10:55:55.11

33.17

137.94 292

7.1 IL 64.77 -146.89

305.8 GOOD

GOOD

GOOD

2009

8 10

20:07:09.11

34.74

138.26 40 6.2 IL 64.77 -146.89

307.3 POOR

GOOD

GOOD

2009

8 12

22:48:51.42

32.82

140.4 53 6.6 IL 64.77 -146.89

306.5 GOOD

GOOD

GOOD

2009

9 24

07:16:20.26

18.83

-107.34

13 6.4 IL 64.77 -146.89

307.1

2009

10 13

05:37:23.69

52.75

-167 24 6.5 IL 64.7714

-146.89

344.2

2009

10 13

20:21:53.20

52.6 -167.12

14 6.4 IL 64.77 -146.89

344.0

2009

11 17

15:30:47.44

52.12

-131.4 17 6.6 IL 64.77 -146.89

345.0

2010

1 10

00:27:39.32

40.65

-124.69

29 6.5 IL 64.77 -146.89

332.7

2010

3 14

08:08:03.96

37.74

141.59 32 6.5 IL 64.77 -146.89

311.2

2010

4 4 22:40:43.10

32.3 -115.28

4 7.2 IL 64.77 -146.89

322.2

2010

4 4 23:15:13.89

32.33

-115.02

0 6.2 IL 64.77 -146.89

322.1

2010

6 18

02:23:05.58

44.45

148.69 28 6.2 IL 64.77 -146.89

319.8

2010

7 4 21:55:51.98

39.7 142.37 27 6.3 IL 64.7714

-146.89

313.2

2010

7 18

05:56:44.93

52.88

-169.85

14 6.7 IL 64.77 -146.89

343.3

2010

7 30

03:56:13.71

52.5 159.84 23 6.3 IL 64.77 -146.89

330.7

2010

8 4 12:58:24.20

51.42

-178.65

27 6.4 IL 64.7714

-146.89

338.9

2010

8 10

05:50:33.27

39.41

143.32 0 6.4 IL 64.77 -146.89

313.4 POOR

DIFF POOR

2010

9 3 11:16:06.60

51.45

-175.87

23 6.5 IL 64.77 -146.89

340.0

2010

10 8 03:26:13.71

51.37

-175.36

19 6.4 IL 64.77 -146.89

340.1 GOOD

DIFF GOOD

2010

10 21

17:53:13.57

24.7 -109.16

13 6.7 IL 64.77 -146.89

313.1

2010

12 21

17:19:40.66

26.9 143.7 14 7.4 IL 64.77 -146.89

302.8 GOOD

GOOD

NONE

2010

12 22

21:49:40.08

26.81

143.6 18 6.4 IL 64.77 -146.89

302.7 GOOD

GOOD

GOOD

2010

12 23

14:00:32.33

53.13

171.16 18 6.4 IL 64.77 -146.89

336.0

2011

3 9 02:45:20.33

38.44

142.84 32 7.3 IL 64.7714

-146.89

312.4

2011

3 9 02:58:8.90

38.27

143.13 0 6.3 IL 64.77 -146.89

312.3

2011

3 9 04:36:59.11

38.63

143.11 0 6.0 IL 64.77 -146.89

312.6

2011

3 9 18:16:16.44

38.31

142.43 22 6.0 IL 64.77 -146.89

312.1

2011

3 9 21:23:59.39

38.32

142.79 0 6.6 IL 64.77 -146.89

312.2 GOOD

DIFF GOOD

2011

3 11

05:46:24.12

38.3 142.37 29 9.0 IL 64.77 -146.89

312.0

2011

3 11

06:08:29.66

38.97

143.37 2 6.7 IL 64.77 -146.89

313.0

2011

3 11

06:11:10.93

36.08

141.83 0 7.0 IL 64.77 -146.89

309.9

2011

3 11

06:12:36.36

37.79

144.23 25 6.2 IL 64.77 -146.89

312.4

2011

3 11

06:15:23.12

37.93

143.8 35 6.3 IL 64.77 -146.89

312.3

2011

3 11

06:23:09.48

39.03

142.28 56 6.2 IL 64.77 -146.89

312.6

2011

3 11

06:25:50.30

38.06

144.59 18 7.7 IL 64.77 -146.89

312.8 GOOD

NONE

NONE

2011

3 11

06:29:15.99

37.81

144.23 40 6.1 IL 64.77 -146.89

312.4

2011

3 11

06:48:45.59

37.96

142.72 11 6.2 IL 64.77 -146.89

311.9

2011

3 11

06:49:16.61

37.34

144.24 47 6.1 IL 64.77 -146.89

312.0

2011

3 11

06:55:27.28

37.55

142.9 0 6.9 IL 64.77 -146.89

311.6

2011

3 11

06:58:53.69

37.23

144.76 0 6.7 IL 64.77 -146.89

312.2

2011

3 12

01:35:25.26

39.18

142.97 0 6.0 IL 64.77 -146.89

313.0

2011

3 12

01:43:21.02

36.37

141.62 38 6.3 IL 64.77 -146.89

310.1

2011

3 12

01:47:15.40

37.59

142.65 20 6.5 IL 64.77 -146.89

311.6 POOR

DIFF POOR

2011

3 13

01:26:04.25

35.72

141.64 8 6.1 IL 64.77 -146.89

309.5 GOOD

GOOD

GOOD

2011

3 14

06:12:36.06

37.78

142.46 14 6.0 IL 64.77 -146.89

311.6

2011

3 15

15:23:54.13

40.33

143.29 19 6.1 IL 64.77 -146.89

314.1

2011

3 22

07:18:45.38

37.24

144 11 6.4 IL 64.77 -146.89

311.8 GOOD

NONE

GOOD

2011

3 22

09:19:06.23

37.33

141.79 31 6.1 IL 64.77 -146.89

311.0

2011

3 22

09:44:28.42

39.85

143.44 7 6.4 IL 64.77 -146.89

313.8 POOR

NONE

GOOD

2011

3 25

11:36:24.49

38.77

141.88 39 6.2 IL 64.77 -146.89

312.2 POOR

DIFF POOR

2011

3 27

22:23:58.80

38.42

142.01 19 6.2 IL 64.77 -146.89

312.0 POOR

NONE

GOOD

2011

3 29

10:54:33.20

37.4 142.29 15 6.1 IL 64.77 -146.89

311.2

2011

4 7 14:32:43.29

38.28

141.59 42 7.1 IL 64.77 -146.89

311.7 POOR

DIFF GOOD

2011

4 11

08:16:12.73

37 140.4 11 6.6 IL 64.77 -146.89

310.1 GOOD

POOR

POOR

2011

4 11

23:08:16.87

35.42

140.57 15 6.2 IL 64.77 -146.89

308.8 POOR

POOR

POOR

201 4 1 19:57:25. 39.5 143.34 22 6.0 IL 64.77 - 313.5

1 3 42 8 146.892011

6 22

21:50:52.35

39.96

142.21 33 6.7 IL 64.77 -146.89

313.4

2011

6 24

03:09:39.47

52.05

-171.84

52 7.3 IL 64.7714

-146.89

341.9

2011

7 10

00:57:10.80

38.03

143.26 23 7.0 IL 64.77 -146.89

312.2 POOR

DIFF POOR

2011

7 23

04:34:24.18

38.9 141.82 41 6.3 IL 64.7714

-146.89

312.3

2011

7 30

18:53:49.68

36.94

140.96 30 6.3 IL 64.7714

-146.89

310.3

2011

8 22

11:23:32.75

36.1 141.79 0 6.0 IL 64.77 -146.89

309.9

2011

9 2 10:55:53.59

52.17

-171.71

32 6.9 IL 64.77 -146.89

342.1 POOR

DIFF POOR

2011

9 9 19:41:34.15

49.53

-126.89

22 6.4 IL 64.77 -146.89

341.4

2011

9 15

08:00:09.64

36.26

141.34 28 6.1 IL 64.77 -146.89

309.9

2011

9 16

19:26:40.97

40.27

142.78 35 6.7 IL 64.77 -146.89

313.9 POOR

DIFF POOR

2011

12 11

01:47:25.90

17.84

-99.96 54 6.5 IL 64.77 -146.89

303.6

2011

12 27

15:21:56.84

51.84

95.91 15 6.6 IL 64.77 -146.89

306.1 POOR

POOR

NONE

2001

8 2 23:41:06.17

56.26

163.79 14 6.3 YK 62.49 -114.61

320.7

2001

8 13

20:11:23.40

41.05

142.31 38 6.4 YK 62.49 -114.61

300.1 POOR

POOR

POOR

2001

10 8 18:14:26.44

52.59

160.32 48 6.5 YK 62.49 -114.61

316.6 POOR

DIFF NONE

2002

4 18

05:02:46.19

16.99

-100.86

24 6.8 YK 62.49 -114.61

313.5 GOOD

DIFF GOOD

2002

5 25

05:36:31.97

53.81

-161.12

33 6.4 YK 62.4932

-114.61

334.5

2002

6 16

02:46:14.03

8.78 -83.99 35 6.4 YK 62.49 -114.61

301.9 POOR

POOR

POOR

2002

7 31

00:16:44.61

7.93 -82.79 10 6.5 YK 62.49 -114.61

300.8

2002

10 3 16:08:29.62

23.32

-108.53

10 6.5 YK 62.49 -114.61

320.6

2002

10 19

12:09:05.38

44.3 149.96 33 6.3 YK 62.4932

-114.61

305.9

2002

10 23

11:27:19.43

63.51

-147.91

4 6.7 YK 62.49 -114.61

345.0 POOR

POOR

POOR

2002

11 3 22:12:41 63.52

-147.44

4 7.9 YK 62.49 -114.61

345.2

2002

11 3 23:11:48.87

63.05

-143.64

0 6.5 YK 62.49 -114.61

346.8

2002

11 7 15:14:06.76

51.2 179.33 33 6.6 YK 62.49 -114.61

323.9

2003

1 16

00:53:15.72

44.28

-129.02

10 6.3 YK 62.49 -114.61

339.9

2003

1 21

02:46:47.74

13.63

-90.77 24 6.5 YK 62.4932

-114.61

308.3

2003

1 22

02:06:34.61

18.77

-104.1 24 7.6 YK 62.49 -114.61

315.7

2003

2 19

03:32:36.36

53.65

-164.64

19 6.6 YK 62.49 -114.61

332.8

2003

3 12

23:41:32.92

26.56

-110.59

10 6.4 YK 62.4932

-114.61

324.0

2003

3 17

16:36:17.31

51.27

177.98 33 7.1 YK 62.49 -114.61

323.3 POOR

DIFF POOR

2003

5 14

06:03:35.86

18.27

-58.63 41 6.7 YK 62.49 -114.61

301.5 GOOD

GOOD

GOOD

2003

6 15

19:24:33.15

51.55

176.92 20 6.5 YK 62.49 -114.61

323.0 GOOD

DIFF GOOD

2003

6 16

22:08:02.14

55.49

160 174

6.9 YK 62.49 -114.61

318.6 GOOD

NONE

GOOD

2003

6 23

12:12:34.47

51.44

176.78 20 6.9 YK 62.4932

-114.61

322.9

2003

9 22

04:45:36.24

19.78

-70.67 10 6.4 YK 62.49 -114.61

307.8

2003

9 25

19:50:06.36

41.81

143.91 27 8.3 YK 62.49 -114.61

301.4

2003

9 29

02:36:53.14

42.45

144.38 25 6.5 YK 62.49 -114.61

302.1

2003

9 29

21:33:16.74

41.45

143.98 0 6.0 YK 62.49 -114.61

301.1

2003

10 8 09:07:0.44

42.61

144.5 68 6.5 YK 62.49 -114.61

302.3

2003

11 17

06:43:06.80

51.15

178.65 33 7.8 YK 62.49 -114.61

323.5 POOR

DIFF NONE

2003

12 5 21:26:09.48

55.54

165.78 10 6.7 YK 62.49 -114.61

321.0 POOR

NONE

POOR

2003

12 22

19:15:56 35.71

-121.1 7 6.6 YK 62.49 -114.61

332.9 POOR

DIFF POOR

2003

12 25

07:11:11.59

8.42 -82.82 33 6.5 YK 62.49 -114.61

301.2 GOOD

GOOD

GOOD

2004

4 29

00:57:21.08

10.81

-86 10 6.2 YK 62.49 -114.61

304.4 POOR

POOR

POOR

2004

5 3 05:12:39.95

14.5 -90.57 120

6.0 YK 62.49 -114.61

309.1 POOR

POOR

POOR

2004

6 10

15:19:57.75

55.68

160 188

6.9 YK 62.49 -114.61

318.8 POOR

DIFF POOR

2004

6 28

09:49:47 54.8 -134.25

20 6.8 YK 62.49 -114.61

347.3

2004

7 19

08:01:49.46

49.62

-126.97

23 6.4 YK 62.4932

-114.61

345.4

2004

10 9 21:26:53.69

11.42

-86.67 35 7.0 YK 62.49 -114.61

305.2 GOOD

GOOD

GOOD

2004

11 2 10:02:12.82

49.28

-128.77

10 6.7 YK 62.4932

-114.61

344.6

2004

11 20

08:07:22.08

9.6 -84.17 16 6.4 YK 62.4932

-114.61

302.7

2004

12 6 14:15:11.89

42.9 145.23 35 6.8 YK 62.49 -114.61

302.8 GOOD

POOR

POOR

2004

12 14

23:20:13.36

18.96

-81.41 10 6.8 YK 62.49 -114.61

310.8

2004

12 18

06:46:19.87

48.84

156.31 11 6.2 YK 62.49 -114.61

312.1 POOR

DIFF POOR

2005

3 6 05:21:43.43

84.95

99.39 10 6.3 YK 62.49 -114.61

328.1 GOOD

DIFF GOOD

2005

6 14

17:10:12.28

51.24

179.31 17 6.8 YK 62.4932

-114.61

323.9

2005

6 15

02:50:54.19

41.29

-125.95

16 7.2 YK 62.4932

-114.61

337.7

2005

6 27

11:35:45.60

18.78

-107.3 20 6.2 YK 62.4932

-114.61

316.0

2005

7 2 02:16:43.70

11.24

-86.17 27 6.6 YK 62.49 -114.61

304.9 GOOD

POOR

POOR

2005

8 3 11:03:15.13

11.25

-85.54 14 6.3 YK 62.49 -114.61

304.7 POOR

POOR

POOR

2006

1 4 08:32:32.40

28.16

-112.12

14 6.6 YK 62.49 -114.61

325.6

2006

4 20

23:24:58.39

60.93

167.02 0 7.5 YK 62.49 -114.61

325.0 GOOD

DIFF GOOD

2006

4 20

23:28:03.90

60.87

167.01 10 6.1 YK 62.49 -114.61

325.0

2006

4 29

16:58:06.32

60.49

167.52 11 6.6 YK 62.49 -114.61

324.9 POOR

DIFF GOOD

2006

5 10

02:42:51.03

52.51

-169.26

18 6.4 YK 62.49 -114.61

329.9 GOOD

DIFF GOOD

200 5 2 11:11:57. 60.7 165.71 0 6.7 YK 62.49 - 324.4 POO NON POO

6 2 47 9 114.61 R E R2006

6 14

04:18:42.51

51.75

177.08 14 6.5 YK 62.49 -114.61

323.2

2006

7 8 20:40:00.98

51.21

-179.31

22 6.6 YK 62.49 -114.61

324.5

2006

7 8 20:41:47.66

51.4 -179.22

0 6.5 YK 62.49 -114.61

324.6

2006

8 24

21:50:36.65

51.15

157.52 43 6.5 YK 62.49 -114.61

314.4

2006

9 30

17:50:23.05

46.35

153.17 11 6.6 YK 62.49 -114.61

308.9 POOR

POOR

POOR

2006

10 1 09:06:02.32

46.47

153.24 19 6.5 YK 62.49 -114.61

309.0

2006

10 1 09:09:57.97

46.45

153.16 0 6.8 YK 62.49 -114.61

308.9

2006

10 15

17:07:49.25

19.88

-155.93

38 6.7 YK 62.49 -114.61

308.9 POOR

POOR

POOR

2006

11 15

11:14:13.57

46.59

153.27 10 8.3 YK 62.49 -114.61

309.1

2006

11 15

11:29:22.79

46.37

154.48 10 6.2 YK 62.49 -114.61

309.4

2006

11 15

11:40:55.05

46.48

154.73 10 6.7 YK 62.49 -114.61

309.6 POOR

POOR

POOR

2006

12 7 19:10:21.85

46.15

154.39 16 6.4 YK 62.4932

-114.61

309.2

2007

1 13

04:23:21.16

46.24

154.52 10 8.1 YK 62.49 -114.61

309.3 GOOD

GOOD

GOOD

2007

4 5 03:56:50.48

37.31

-24.62 14 6.3 YK 62.49 -114.61

302.4 GOOD

GOOD

NONE

2007

6 13

19:29:40.18

13.55

-90.62 23 6.7 YK 62.49 -114.61

308.2

2007

8 2 03:21:42.82

51.31

-179.97

21 6.7 YK 62.49 -114.61

324.2 POOR

NONE

POOR

2007

8 15

20:22:11.12

50.32

-177.55

9 6.5 YK 62.49 -114.61

324.7 GOOD

NONE

GOOD

2007

10 2 18:00:06.87

54.51

-161.71

32 6.3 YK 62.49 -114.61

334.7

2007

11 29

19:00:20.42

14.94

-61.27 156

7.4 YK 62.49 -114.61

299.6 GOOD

GOOD

POOR

2007

12 19

09:30:27.93

51.36

-179.51

34 7.2 YK 62.49 -114.61

324.5 GOOD

DIFF GOOD

2007

12 19

09:35:13.87

51.07

-179.16

0 7.1 YK 62.49 -114.61

324.4

2007

12 21

07:24:34.03

51.37

-178.98

25 6.3 YK 62.49 -114.61

324.7 GOOD

NONE

GOOD

2007

12 26

22:04:54.67

52.56

-168.22

25 6.4 YK 62.4932

-114.61

330.5

2008

1 5 11:01:06.11

51.25

-130.75

15 6.6 YK 62.49 -114.61

345.8

2008

1 5 11:44:48.17

51.16

-130.54

10 6.4 YK 62.49 -114.61

345.8

2008

3 3 09:31:02.50

46.41

153.18 10 6.5 YK 62.49 -114.61

308.9 GOOD

GOOD

GOOD

2008

4 12

00:46:28.17

43.91

147.55 66 6.1 YK 62.49 -114.61

304.6

2008

4 15

22:59:51.50

51.86

-179.36

11 6.4 YK 62.4932

-114.61

324.9

2008

4 16

05:54:19.69

51.88

-179.16

13 6.6 YK 62.49 -114.61

325.0 GOOD

DIFF GOOD

2008

5 2 01:33:37.24

51.86

-177.53

14 6.6 YK 62.4932

-114.61

325.7

2008

5 29

15:45:59.37

64.01

-21.11 0 6.2 YK 62.49 -114.61

321.6 GOOD

DIFF GOOD

2008

9 11

00:20:50.92

41.89

143.75 25 6.8 YK 62.49 -114.61

301.4

2008

9 24

02:33:05.56

17.61

-105.5 12 6.4 YK 62.49 -114.61

314.7

2008

10 16

19:41:25.72

14.42

-92.36 24 6.7 YK 62.49 -114.61

309.4

2008

10 16

19:43:34.32

14.38

-92.28 0 6.4 YK 62.49 -114.61

309.4

2009

1 15

17:49:39.07

46.86

155.15 36 7.4 YK 62.4932

-114.61

310.1

2009

3 6 10:50:29.41

80.32

-1.85 9 6.5 YK 62.49 -114.61

327.5 GOOD

DIFF POOR

2009

4 7 04:23:33.15

46.05

151.55 31 6.9 YK 62.49 -114.61

308.0 GOOD

GOOD

GOOD

2009

4 18

19:18:0.11

46.04

151.46 42 6.4 YK 62.49 -114.61

307.9 GOOD

GOOD

GOOD

2009

5 28

08:24:46.56

16.73

-86.22 19 7.3 YK 62.4932

-114.61

310.1

2009

6 5 03:30:33.06

41.82

143.45 29 6.4 YK 62.49 -114.61

301.2

2009

8 3 17:59:56.17

29.04

-112.9 10 6.9 YK 62.49 -114.61

326.5 GOOD

NONE

POOR

2009

8 3 18:40:50.10

29.31

-113.73

10 6.2 YK 62.49 -114.61

326.8

2009

9 24

07:16:20.26

18.83

-107.34

13 6.4 YK 62.49 -114.61

316.1

2009

10 13

05:37:23.69

52.75

-167 24 6.5 YK 62.49 -114.61

331.1

2009

10 13

20:21:53.20

52.6 -167.12

14 6.4 YK 62.49 -114.61

331.0

2009

11 17

15:30:47.44

52.12

-131.4 17 6.6 YK 62.49 -114.61

346.3

2010

1 10

00:27:39.32

40.65

-124.69

29 6.5 YK 62.49 -114.61

337.3 GOOD

DIFF GOOD

2010

1 12

21:53:10.06

18.44

-72.57 13 7.0 YK 62.49 -114.61

307.3 POOR

POOR

POOR

2010

4 4 22:40:43.10

32.3 -115.28

4 7.2 YK 62.49 -114.61

329.8

2010

4 4 23:15:13.89

32.33

-115.02

0 6.2 YK 62.49 -114.61

329.8

2010

6 18

02:23:05.58

44.45

148.69 28 6.2 YK 62.49 -114.61

305.5 POOR

POOR

POOR

2010

7 18

05:56:44.93

52.88

-169.85

14 6.7 YK 62.49 -114.61

329.9 GOOD

DIFF GOOD

2010

7 30

03:56:13.71

52.5 159.84 23 6.3 YK 62.49 -114.61

316.4

2010

8 4 12:58:24.20

51.42

-178.65

27 6.4 YK 62.49 -114.61

324.9 POOR

DIFF POOR

2010

9 3 11:16:06.60

51.45

-175.87

23 6.5 YK 62.4932

-114.61

326.2

2010

10 8 03:26:13.71

51.37

-175.36

19 6.4 YK 62.49 -114.61

326.4 POOR

DIFF GOOD

2010

12 23

14:00:32.33

53.13

171.16 18 6.4 YK 62.4932

-114.61

321.6

2011

6 24

03:09:39.47

52.05

-171.84

52 7.3 YK 62.49 -114.61

328.5 GOOD

DIFF GOOD

2011

9 2 10:55:53.59

52.17

-171.71

32 6.9 YK 62.49 -114.61

328.6 GOOD

DIFF GOOD

2011

9 9 19:41:34.15

49.53

-126.89

22 6.4 YK 62.49 -114.61

345.4 POOR

DIFF POOR

2011

9 16

19:26:40.97

40.27

142.78 35 6.7 YK 62.4932

-114.61

299.6

2011

12 11

01:47:25.90

17.84

-99.96 54 6.5 YK 62.4932

-114.61

314.2

Supplementary Table 2. Slowness and back-azimuth residuals from resolution tests for Elison and Yellowknife arrays. For each slowness, synthetic signals were generated from -180 to 135° back-azimuth, in 45° increments.

Eilson YellowknifeInput slowness (s/deg)

Average back-azimuth residual (°)

Standard deviation

Average slowness residual (s/deg)

Standard deviation

Average back-azimuth residual (° ¿

Standard deviation

Average slowness residual (s/deg)

Standard deviation

0.0 90.0 52.3 1.6 0.0 90.0 50.4 0.4 00.5 79.8 52.0 1.1 0.4 20.3 11.9 0.2 0.11.0 68.3 50.4 0.7 0.5 9.0 5.6 0.2 0.11.5 48.0 35.1 0.7 0.4 6.8 4.6 0.2 0.12.0 25.8 13.0 0.7 0.4 6.0 2.9 0.2 0.12.5 19.3 10.6 0.7 0.4 5.2 2.7 0.1 0.13.0 15.8 8.9 0.7 0.4 3.8 2.3 0.1 0.13.5 13.8 7.3 0.7 0.4 3.2 1.6 0.1 0.04.0 11.3 6.5 0.7 0.4 2.8 1.4 0.1 0.14.5 9.8 4.6 0.7 0.4 2.5 1.1 0.2 0.15.0 8.8 4.1 0.7 0.4 2.3 1.0 0.2 0.15.5 8.0 4.6 .7 0.5 1.8 1.2 0.2 0.16.0 7.0 4.2 0.7 0.5 1.5 0.9 0.2 0.1

Supplementary Table 3: coefficients to fit velocity anomalies with equation 1 Anisotropy magnitude (%)

a b c RMS Misfit

Original 0.494 0.039 0.502 -0.008 0.755Bootstrap sampled

0.483 0.037 0.576 -0.093 0.787

No anisotropy

0 0 0 0 0.829

Supplementary Table 4: details of events used, including relative P′P′ab-df and P′P′bc-df, and P′P′df absolute travel time anomalies, pick qualities, polar angles ξ1 and ξ2, and event-receiver distances, sufficient to recreate figures shown in the paper.