Change of pore space due to mechanical compaction is common in the crust. It is well known that porosity decreases as a function of the burial depth. In general, porosity can increase or decrease to accommodate strain in deformed rocks. Dilation bands in poorly lithified sediments near McKinleyville, northern California show approximately 7% (+-3%) porosity increase within the band. Compaction bands in Aztec sandstone of Valley of Fire State Park in southeastern Nevada show a porosity decrease of more than 50%. Please see the section 'Porosity of Deformation Bands' and 'Fractures in McKinleyville, N. CA, USA'.