Intact rock samples pulled from two miles below the surface of the San Andreas Fault could answer fundamental questions about the zone. “Now we can hold the San Andreas Fault in our hands. We know what it’s made of. We can study how it works,” said Mark Zoback of Stanford, one of the principal investigators on the San Andreas Fault Observatory at Depth project.

Zoback and colleagues drilled a ton of rock from the active fault, in cores 4 inches wide totalling 135 feet in length. Serpentine contained in the rock could explain why the fault slides relatively easily, this mineral forms talc in certain conditions. Previous drilling by SAFOD detected talc (reported at the time in Nature, with an accompanying news and views) and the new cores could provide more details.

The best part of the press release has been picked up by the LA Times: “The scientists will hold a ‘sample party’ in December to show the cores to experts from around the world and invite them to propose research projects.” The new samples will help determine the exact make up of the fault as well as what happens when stress builds up, according to AP. Sadly, as PA notes, the cores will not help actually predict earthquakes. “That goal is still out of reach, despite a century of research into earthquake physics.”

Image: San Andreas fault / Punch Stock