A team of scientists today showed off the first rock samples taken from a borehole being drilled into the mighty San Andreas Fault to better understand how earthquakes are born.
The 4-inch-wide rock cores were pulled earlier this month from two miles beneath a seismically active section of the fault halfway between San Francisco and Los Angeles.
Researchers hope the core collection, weighing about a ton in total, will help answer questions about the fault's makeup and determine what happens during stress buildup at great depths.
As excited as scientists worldwide are about the rock cores, they likely won't help in earthquake prediction.
That goal is still out of reach despite a century of research into earthquake physics.
Last summer, scientists penetrated an active section of the fault for the first time and began the arduous process of extracting rock samples to the surface.
A preliminary analysis revealed the rupture zone contains very fine ground-up rock containing a greenish mineral called serpentine that may explain why the region of the fault creeps slowly to relieve stress.