[Triumf-seminars] TRIUMF Seminar today at 14:00

[postmaster at admin.triumf.ca]

Date/Time: Tue 2009-01-13 at 14:00

Location:  Auditorium          

Speaker:   Danny Abrams (MIT)

Title:     Growth Laws for Channel Networks

Abstract: Enigmatic channel networks have been observed around the Earth and on Mars. Evidence suggests that these channels were carved not by overland flow, but by groundwater seeping from the soil at springs. Here we explore how networks of seepage-driven channels grow.

We study a heavily-branched channel network cut through several kilometers of sand on the Florida Panhandle.  Using ground-penetrating radar, we obtain a three-dimensional survey of the subsurface water table.  This survey leads us to propose a simplified 2D model in which the flow of groundwater is determined solely by the geometry of the channel network.  We show that the flux of groundwater to channel heads is proportional to the velocity at which channel heads advance. This linear growth law implies that the system is reversible, and allows us to reconstruct the network's growth.

Stimulants available 15 minutes before the talk.

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