OTD 3 years ago the French town of Le Teil was severely shaken by a very shallow M4.9 earthquake. Here is the causative fault zone, a few 10 m undergound, squirting fluids, as seen in one of the boreholes we drilled through it.
We drill to sample fault rocks. We then take the rocks to the lab and study their properties to try to solve outstanding puzzles about the Le Teil earthquake: how come it started at such shallow depth? can that happen again in nearby faults?
@DocTerremoto Super cool! Did you do any geophysical well logging too?
@DocTerremoto Wow! This completely changes my mental image of fluid flow around fault zones. I had always imagined this slow, leaking flow. The fact that fluids can squirt out blows my mind. Does this mean local regions of permeability enhancement?