|WikiProject Glaciers||(Rated C-class, High-importance)|
The section on crevasse types needs some attention from someone who understands solid mechanics. Consider, for instance, the following statement:
Longitudinal crevasses form parallel to flow where the glacier width is expanding. They develop in areas of compressive stress, such as where a valley widens.
As an engineer, I believe this is simply not true. Compressive stresses by themselves cannot cause a fissure to open, nor do they form when a valley widens. The stresses form in narrow spots, when the valley walls push in on the ice and compress it. When the valley opens up, the stresses are released. If the bottom of the glacier is more stressed than the surface (easy to imagine), it will expand more, and pull apart the surface layers.
- I've actually never really heard the term longitudinal crevasses in the literature, specifically in Nye's seminal paper on crevasse patters where he describes the relevant stress tensors. According to him, there is only splaying and transverse. I think what the above writer was trying to say, was that "width expanding" is equal to lateral extension, whereas compressive stress is longitudinal, often seen at the terminus of the glacier. Under compressive stress you'll see splaying crevasses, which do approach a longitudinal orientation eventually.
crevice versus crevasse
According to Merriam-Webster's Collegiate Dictionary, a crevice is "a narrow opening resulting from a split or crack (as in a cliff)" and a crevasse is "!. a breach in a levee 2. a deep crevice or fissure (as in a glacier or the earth)". So the very first sentence of this article seems to be inaccurate, since crevasse is basically being defined as a deep crevice, and the definition of crevasse includes both ice and "earth."