Figure 3
From: Dynamic vulnerability revealed in the collapse of an Arctic tidewater glacier
Observational timeline of glacier collapse. Heavily crevassed areas return high backscatter (bright) in winter radar images. Monthly compiled Envisat ASAR images (a) show the development of a new shear margin from Bulge 3 in the last 3 months of 2008. The magnitude distribution of NGS seismic events in relation to the 2008 Storfjord earthquake located about 50 km to the west is shown in (b). Seismic moment estimated from local magnitudes (c) define the timing of the collapse. Locations of the largest 96 seismic events shown with error ellipses in (d). Red/blue colors represent the locations and errors when determined from Longyearbyen/Hornsund (Fig. 1c), respectively. Radarsat-2 images every 24 days in the first four months of 2009 (e) show the mechanical destabilization of the remaining sticky spot in February. Seismic event locations over the central region of Zawadzkibreen (d) coincide with large rifts and damaged ice areas seen on a high resolution June 2009 image (f).
