Short Period Motion Events On Variegated Glacier as Observed By Automatic Photography and Seismic Methods

Abstract

A network of automated time-lapse cameras was deployed on Variegated Glacier, Alaska, to establish the temporal and spatial patterns of velocity change at a one-day time resolution. Results from the summers of 1979, 1980, and 1981 are presented; a surge occurred in 1982 and 1983. The principal velocity variations were pulses of increased speed, lasting about one day and referred to as “early”- or “late”-season motion events. The former recurred quasi-periodically on the upper part of the glacier in the early part of the melt season; the latter occurred later in the summer and were correlated with major storms or melting. Supplemental information about the occurrence of motion events was obtained from monitoring of seismic activity. Evidence for several other types of velocity changes was found.