— High tensile stresses and strain rates cause garnet pulverization. Frictional sliding causes melting and results in fault lubrication. Results highlight brittle failure as underlying mechanism for deep earthquakes.

 — The experiments carried out at a strain rate higher than 150 s −1 produced finely broken samples, whereas those carried out below 100 s −1 gave samples broken into two or three fragments .

 — Pulverized rocks occur tens of meters from faults, yet coseismic compressive stresses do not exceed rock strength beyond a few centimeters. We designed a new experimental method to test dynamic rock strength and fragmentation behavior under 2-D isotropic tension.

 — Can the high strain rates required for pulverization by the dynamic fragmentation be achieved tens to hundreds metres away from the fault? And how well do impact-loading experiments simulate what rock near …

 — Besides the upper bound of the fragment size, the critical strain rate characterizing the transition of the fragmentation pattern from split to pulverization is increased as the fracture strength is enhanced.

strain rate depends on the speed of fracture propagation and on the interaction between cracks, controlled by the statistics of the initial crack population and the size of the stress shadow zones around each crack.

 — However, at higher loading rates (Fig. 4c, f, i and l), a global granular crushing failure can be found in both WG and FM. FM is most seriously broken into fragments; the majority of the FM fragments become a powder, as shown in Fig. 4i and l.

 — The pulverization threshold of strain rate, defined for single or succussive dynamic loading, is an important parameter for rock failure under dynamic compression or tensile loading (Aben et al. 2016; Doan and Gary 2009; Yuan et al. 2011). Using the triaxial Hopkinson techniques, here, we present the critical shear strain-rate of rock rupture ...

 — Pulverized rocks have been found in the damage zone around the San Andreas Fault, at distances greater than 100 m from the fault core. This damage is atypical in that it is pervasive and strain is not localized along main fractures as expected at these distances from the fault core.

 — The research method used in this study could provide support for the investigation of breakage characteristics of agricultural granular materials, and the established model between the pulverization rate and energy can provide a quality assessment of particles under different loading conditions.