How mantle heterogeneities drive continental subduction and magmatism in the Apennines.

Petrologic and geophysical observations floored the paradigm shift on the subduction of the continental lithosphere. In long-lived collisional boundaries like the Alpine Himalaya belt, portions of continental lithosphere are pushed down to great depths and then exhumed, as testified by outcrops of UHP materials. The Mediterranean region is a clear expression of this enigmatic process.

Across-Fault Velocity Gradients and Slip Behavior of the San Andreas Fault Near Parkfield.

A long-lasting question in earthquake physics is why slip on faults occurs as creep or dynamic rupture. We compute passive measurements of the seismic wave velocity gradient across the San Andreas Fault near Parkfield, where this transition of slip mode occurs at a scale of a few kilometers. Unbiased measurements are obtained through the application of a new Bayesian local earthquake tomographic code that avoids the imposition of any user-defined, initial velocity-contrast across the fault, or any damping scheme that may cause biased amplitude in retrieved seismic velocities.