Self-Organization in Landscapes

Bernard Hallet

Director, Quaternary Research Center
University of Washington, Seattle, WA

Self-Organization in landscapes leads to striking patterns and features at scales ranging from 1 to 10⁶ m. The geometric regularity and beauty of some of the patterns in nature elicit a sense of wonder. Obvious questions arise: how can these form naturally and why?

They merit considerable attention not only because of their intrinsic interest, but because they manifest complex interactions between system components under exceptional conditions, which tend to be particularly instructive. Clear patterns emerge either where material properties are unusually uniform, or where the underlying processes are exceptionally active, which makes them ideal for study. In addition, surface patterns contain rich information about the properties and processes active in the less accessible subsurface.

Polygons in Antarctica

About the Lecturer

Bernard Hallet has considerable experience in studying diverse processes that shape landscapes primarily in mountainous and polar regions. He has worked extensively on the process of freezing in diverse earth materials and its natural consequences, including frost attack on rocks and soil heaving. His studies on erosion range from detailed analyses of the mechanics of glacial erosion and measurements of sediment yields from glaciated basins using modern instrumentation, to theoretical and field studies of the linkage between climate, tectonics and erosion in regions of extreme relief. A recent theme addressed in his research is the origin and dynamics of subsurface ice in polar regions.

Relevant Publications

In prep. W. Haeberli, B. Hallet, R. Elconin, O. Humlum, A. Kääb, V. Kaufmann, B. Ladanyi, N. Matsuoka, S. Springman, and D. Vonder Mühll. Permafrost Creep and Rock Glacier Dynamics. Final report of the International Permafrost Association/ICSI Task Force, Permafrost and Periglacial Processes, ~30 pages.

Hallet, B., J. Putkonen, R. S. Sletten and J. N. Potter, 2004: Advances in Permafrost Process Research in the United States since 1960s. The Quaternary Period in the United States. A. Gillespie, S. P. Porter and B. Atwater. Amsterdam, Elsevier: 127-145.

Rignot, E., B. Hallet and A. Fountain, 2002: Rock Glacier Surface Motion in Beacon Valley, Antarctica, from Synthetic-Aperture Radar Interferometry. Geophys. Res. Letters, 29(12), 13,494-7.

Hallet, B., 1990: Self Organization in Freezing Soils: from microscopic ice lenses to patterned ground. Can. J. Phys. 68, 842-852.

Walder, J.S., and Hallet, B., 1985: A theoretical model of the fracture of rock due to freezing. Geological Society of America Bulletin 96(3), 336-346.

More Information

depts.washington.edu/qrc/people/hallet2.html

Bernard Hallet