The “small-world” topology of rock fracture networks

In this contribution we show that natural rock fracture networks, acting as media for the delivery of a variety of geological fluids, can be studied by using the principles of complex systems. Natural networks at different length scales (from the metre to the micrometer) have been analysed by evaluating their connectivity at global and local scale and results show that they share topological properties of “small-worlds”, a class of networks characterised by high global and local transport efficiency. This may have important geological implications for a variety of geological processes related to the transfer of fluids within the Earth, from the delivery of magmas to the Earth surface to the dispersion of pollutants in shallow aquifers.