Orogenesis is the name given to the process of fold mountain building. It
involves at least two movements: horizontal folding of sediments;
In some cases a third movement is the extrusion of volcanic materials to build
up cones with peaks higher than the general level of the mountains.
Here is an animation to illustrate this
Growth of Everest
The Indian Plate is moving into the Eurasian Plate at a rate of 5 cm a year.
Prior to their contact there was an ocean in between the continents called the Tethys Ocean . This filled up with kms of sediment which when the plates
eventually collided, was srapped off to form new continental rock.
both plates consist of continental crust, neither can sink. The land between
them has been buckled and pushed upwards to form the Himalayas. This movement,
which is still taking place, accounts for massive earthquakes which
periodically occur where the plates meet. Evidence suggests that Mount Everest
is increasing in height. Less obvious, however, is the effect of the collision
felt by the whole of India. In January 2001 a major earthquake struck Gujarat ,
India killing over 20,000 and making up to 200,000 homeless
earthquake foci tend to be shallow, probably because there is no longer a
subducting plate beneath the mountains.
The more recent Sichuan earthquake of May 2008 (7.9 Mw) killing an estimated 68,000, was also attributed to the movement of the two plates