Key points are not available for this paper at this time.
Author Posting. © American Geophysical Union, 2013. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Earth Surface 118 (2013): 2585–2599, doi:10.1002/2013JF002858.
Ortiz et al. (Thu,) studied this question.