Jean-Philippe Avouac photoJean-Philippe Avouac Professor of Geology:Director of the Tectonics Observatory:CaltechCaltech logo


Mechanics of Mountain building and the Role of Surface Processes

Collisional orogens result from horizontal compression and thickening of the continental crust, which deforms mainly by thrust faulting. They involve a combination of brittle deformation of the upper crust and ductile deformation of the lower crust. The kinematics of the deformation within an orogen depends on surface processes which redistribute mass at the surface and affect the thermal structure of the crust, hence its rheology. Since surface processes depend on topography, hence a cumulative deformation, mountain building can lead to come coupling between crustal deformation and surface processes. This coupling can lead to some positive feedback and might be a key feature to understand the dynamics of mountain building [Avouc and Burov, 1996; Cattin and Avouac, 2000; Avouac, 2003]. Our numerical models show that, if climate is constant, mountain ranges may attain a steady-state geometry, but there is no certainty that steady-state ever occurs in nature. Most probably the topography is always out of equilibrium due to changing climatic facing.

My main contributions on the subject :

Avouac, J.P., and E. G. Burov, Erosion as a driving mechanism of intracontinental growth?, J. Geopys. Res., 101, 17747-17769, 1996. [PDF]

Cattin, R. & Avouac, J.P. Modeling mountain building and the seismic cycle in the Himalaya of Nepal. J. Geophys. Res, 105, 13,389-13,407, 2000. [PDF]

Cattin R., Martelet, G., Henry, P., Avouac, J.P., Diament, M. and Shakya, Gravity anomalies, crustal structure and thermo-mechanical support of the Himalayas of Central Nepal, Geophys. J. Int., 147, 381-392, 2001. [PDF]

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