The Green's functions example in examples/strikeslip-2d has a contrast in shear modulus across the fault. It uses two separate spatial databases with uniform properties. You can prescribe the same variation in material properties with a single spatial database with variable properties. Other examples demonstrate how use of spatial databases with variation properties. For example, examples/strikeslip-2d/step04_varslip specifies spatially variable slip using a SimpleDB spatial database.
