Auxiliary Material Submission for Paper 2008gl Glacier, fjord, and seismic response to recent large calving events, Jakobshavn Isbrae, Greenland

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1 Auxiliary Material Submission for Paper 28gl35281 Glacier, fjord, and seismic response to recent large calving events, Jakobshavn Isbrae, Greenland Jason Amundson (1), Martin Truffer (1), Martin Luethi (2), Mark Fahnestock (3), Roman Motyka (1), and Michael West (1) (1) Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska, USA (2) Versuchsanstalt fur Wasserbau, Hydrologie und Glaziologie, ETH-Zurich, Zurich, Switzerland (3) Institute for the Study of the Earth, Oceans and Space, University of New Hampshire, Durham, New Hampshire, USA Geophys. Res. Lett., xx, xxxxxx, doi:1.129/28gl35281, 28 This data set contains one table, six figures, and two time-lapse videos. Tables 1. 28gl35281-ts1.txt List of all recorded calving events and associated seismograms (UTC time) from Jakobshavn Isbrae between 13 May 27 and 14 May 28. Figures 2. 28gl35281-ps1.pdf Iceberg motion recorded with a GPS. The dotted line indicates the timing of a calving event. (a) Northing (blue) and easting (red) of the iceberg relative to the southern GPS base station. (b) Flow line coordinates for the time period preceding the calving event. A least-squares regression to this line gives a mean velocity of about 35 m a^ gl35281-ps2.pdf Example of a wave in Ilulissat Harbor, near the fjord mouth, that was produced by a calving event (dotted line). The plot was generated by running a 3-hr high pass filter on the tide data gl35281-ps3.pdf Seismogram generated by the overturning of a large iceberg on 18 May 27 during a period of no calving. The data was corrected for instrument response and passed through a 1--5 Hz band-pass filter. (a--c) Vertical, north, and east components, respectively gl35281-ps4.pdf Comparison of seismograms recorded during a calving event to those recorded during known teleseismic glacial earthquakes. All seismograms have been filtered with a 1--5 Hz band-pass filter. (a) Locally recorded seismogram during the 4 July 27 calving event. This signal was corrected for instrument response. (b) Seismogram recorded at Global Seismic Network (GSN) station SFJD during the same event as in (a). SFJD is located 25 km south of the glacier terminus. (c--e) Seismograms recorded at GSN stations SFJD and SFJ (SFJ was replaced by SFJD in 25) during known teleseismic glacial eartquakes that originated from the terminal region of Jakobshavn Isbrae. The red lines indicate the estimated onset times of the glacial earthquakes [Tsai and Ekstrom, 27].

2 6. 28gl35281-ps5.pdf Glacier motion at one of the optical survey markers (dark blue circle in Figure 1a). The various lines assume constant velocity (blue), constant but non-zero strain rate (red), and strain rates that change at each calving event but otherwise remain constant and non-zero (green). The root mean square errors are 2.49,.47, and.15 m, respectively. Note the distinct break in slope of the blue and red curves on 21 May. Data gaps are due to bad weather gl35281-ps6.pdf Glacier motion at one of the GPS sites (the circled block dot in Figure 1a). De-trended longitudinal (blue), transverse (green), and vertical (red) positions. The 4 July 27 calving event is indicated with a dotted line. Videos 8. 28gl35281-ms1.mov Time-lapse video of a calving event at Jakobshavn Isbrae on 5 June 27. The video runs from 14:1--14:28 UTC. Photos were taken every 1 seconds gl35281-ms2.mov Time-lapse video of a calving event at Jakobshavn Isbrae on 17 August 27. The video runs from 12:42--13:21 UTC. Photos were taken every 5 seconds. References Tsai, V. and G. Ekstrom (27), Analysis of glacial earthquakes, J. Geophys. Res., 112, F3S22, doi:1.129/26jf596.

3 Coordinate (m) 5 a 5 Coordinate (m) 2 1 b 28 May 2 June 7 June Day-Month-27 (UTC)

4 .1 Wave height (m) : 26 July : 27 July 12: 27 July Time-Day-Month-27 (UTC)

5 Displacement (mm) Displacement (mm) Displacement (mm) 1 5 Hz band-pass-filtered seismogram components.1 a vertical.1 9:4 1: 1:2 1:4.1 b north.1 9:4 1: 1:2 1:4.1 c east.1 9:4 1: 1:2 1:4 Time (UTC)

6 Displacement (mm) Displacement (nm) Displacement (nm) Displacement (nm) Displacement (nm) 1 5 Hz band-pass-filtered vertical seismogram components.1 a local seismometer.1 16:3 16:5 17:1 17:3 4 July 27 (UTC) 5 b SFJD 5 16:3 16:5 17:1 17:3 4 July 27 (UTC) 5 c SFJ 5 16:3 16:5 17:1 17:3 6 June 1998 (UTC) 5 d SFJ 5 12: 12:2 12:4 13: 24 April 1999 (UTC) 5 e SFJD 5 :3 :5 1:1 1:3 16 August 25 (UTC)

7 De-trended position (m) July 5 July 6 July Day-Month-27 (UTC)

8 De-trended position (m) July 5 July 6 July Day-Month-27 (UTC)