Plates and Tectonic Activity

At www.physorg.com/print188500078.html March 22nd … a new model of the earth which took 20 years to construct offers a precise description of the relative movements of 25 interlocking tectonic plates over 95 + per cent of the surface of the planet. The model can be used to predict plate movement relative to any other plate. It is remarkably simple in a mathematical way, the research offers. Tectonic plates are in constant motion and collisions and shifts can create mountain ranges or cause earthquakes such as those that struck Haiti and Chile this year. The frequency of earthquakes depends on how tectonic plates move – and why? The research paper is published online in the April issue of Geophysical Journal International. Much of the data comes from the mid-ocean ridges, the undersea boundaries between the plates. At these ridges new crust forms from upwelling magma from beneath the surface – and this is thought to force the plates apart in a continuous process. The model is accessible online at http://www.geology.wisc.edu/~chuck/MORVEL/ but unfortunately nothing is mentioned about analysing the way the plates have moved in the past. If movement had been episodic, in bursts and fits of activity, should not pronounced rupturing be visible?