When   Tuesday, February 10, 2009   Time   2:00 PM - 3:00 PM  
Where   Technological Instit M416 2145 Sheridan Rd.   map it
Audience   - Faculty/Staff - Student - Public
Contact   Molly E Scanlon   +1 847 491 5586  
Group   McCormick-Colloquia Engineering Sciences and Applied Mathematics

Applied Math Colloquium

Title: Growth of a Dendritic Channel Network

Speaker: Daniel H. Rothman, Massachusetts Institute of Technology

Abstract: 

Dendritic channel networks are a ubiquitous feature of Earth's topography. A half century of work has detailed their scale-invariant geometry. But relatively little is known about how such networks grow, especially in natural settings at geologic time scales.
This talk addresses the growth of a particularly simple class of
channel networks: those which drain groundwater. We focus on a pristine field site in the Florida Panhandle, in which channels extending for kilometers have been incised vertically through tens of meters of ancient beach sands.
We first present new field observations showing how the flow of
subsurface water interacts with the geometry of the network. We then show that the growth of groundwater-driven networks is described by two linear response laws. Remarkably, one of these growth laws is reversible, which allows us to reconstruct network history and estimate network age. A particularly striking feature of the Florida network is the existence of a characteristic length scale between channels. Our theory predicts how this length scale evolves, thereby linking network growth to geometric form.

Special Note: Please note unusual day and time. If you would like to meet with the speaker please contact M. Scanlon.