Fracture

Fractures are cracks in the earth surface. If there is no displacement it is a joint. If there is displacement and you are in the brittle zone it is a fault. In the ductile zone, a fracture with displacement with fracture is called a shear. FaultSurface as a separate class is not considered necessary for GeoSciML 2. Recording observations on FaultSurface should be in observation and measurement. The observation needs to be able to distinguish the type of measurement made (PropertyType)