Question 5 to plate tectonics

 Here is one more Question

Question number 5 ...to Plate tectonics 

As per plate tectonics the quakes occur due to built up stresses in the plate boundaries. When the built up stress (due to movement of plates) exceeds it releases the stress and quakes occur

Now we know

1)Plates area 

2) Thickness of plates

3) Average density of plates

Hence we know weight of plates/mass of plates

 Further we know the speed / movement of plates and hence kinetic energy (1/2x mass x square of velocy)

  Now we can have some laboratory test of crust samples to know the shearing force required to break /shear the Earth  rust.

Recently Chhina has drilled a hole in the crust going 10 km  deep inside the crust

  If we take samples of crust from depth and test in laboratory for their shear strength,we can have idea as to when the built pressure will increase th threshold limit

 So now we (plate tectonics) have all things available in our hand

mass ,weight, speed  of plate and hence total kgf

 Further we know the cross section area of plate boundaries and depth of plates .

 hence we can find out built up stresses in kgf/square meter

 Now when this built up stresses exceed the laboratory tested shear strength,the quake will occur ( as per plate tectonics)

So now Question is why we can not calculate built up stresses and compare with laboratory test strength of samples taken from deep inside the crust and predict thr date of major Earthquakes with fair amount of accuracy?