Credit: Courtesy of Laurel Goodwin and Randy Williams, UW-Madison
The white calcite “veins” of the Loma Blanca fault are evident in this slab of rock on the fault. These veins of calcite reveal a record of fluid-driven earthquakes clustered together on a fault typically characterized by less frequent, periodic earthquakes caused by mechanical stress. They helped UW–Madison researchers trace the oldest and longest earthquake record ever documented.