If you want to look at surface displacement from a change in surface albedo, what you're doing is probably photoclinometry. For this, you'll only access the glacier slope variation in the axis aligned with the Sun incidence, and assuming the surface didn't change between acquisitions. I'm skeptical this method can work in your case.
The ideal situation to measure glacier displacement is to have two-pairs of stereo imagery acquired before the Denali EQ, and 2 pairs of stereo acquired after the Denali EQ. If you're looking at velocity variations, you need to create a time series before 2002 and after 2002. Unfortunately, the glaciers in Alaska have sustained a large amount of thinning over the last few decades, and DEM errors will bias you measurements if 3D topography changes are not taken into account. You would then ideally need at least 8 images. You could reduce this number if you can get images with very small incidence angles (<1 degree), so that you're not sensitive to ice thickness change. Unfortunately, no such imagery exists (to my knowledge) over the Denali area.
You can look at this paper, where we incidentally observed glacier velocity:
http://www.tectonics.caltech.edu/slip_h … r_2008.pdf
I've continued the study later with five SPOT images acquired before and after the Denali EQ. I spent a large amount of time on this study and at some point I thought I was able to find a difference in ice velocity due to the EQ. Unfortunately, I realized that my observations were only due to large ice thinning and that horizontal and vertical changes couldn't be disambiguated. I wrote a paper that I never sent for review because I realized that the whole study was flawed. If you're interested, I could send you the paper I wrote on the subject and that I never sent for review because it's all wrong. At least you won't redo the same mistakes. We could discuss it offline.