Material Properties Inc2. The difference between the two layers is that
the "basalt" has a higher SHEAR modulus.
; Properties for each sub-regions: 
;  Basalt
pro dens= 2720  bulk=4.09e10 shear=2.45e9 
pro coh=3.00e7 tens=1.50e7 
pro fric=30 dil= 0  
;  granite
pro dens= 2720  bulk=4.09e10 shear=2.45e8 
pro coh=3.00e7 tens=1.50e7 
pro fric=30 dil= 0