Birch's Law
Encyclopedia
Birch's law establishes a linear relation of the compressional wave velocity vp of rocks and minerals of a constant average atomic weight
Atomic weight
Atomic weight is a dimensionless physical quantity, the ratio of the average mass of atoms of an element to 1/12 of the mass of an atom of carbon-12...

 Mavg with density as:
.

Francis Birch
Francis Birch (geophysicist)
Albert Francis Birch was an American geophysicist best known for his experimental work on the properties of Earth-forming minerals at high pressure and temperature, in 1952 he published a well-known paper in the Journal of Geophysical Research ,where he demonstrated that the mantle is chiefly...

published two papers in 1961, which later became known as Birch's Law.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK