Anthony Lomax 

The predominant model for earthquake faulting is a shear crack, including surrounding damage zones. Observation of this complete shear crack system at seismogenic depth, however, has been elusive. Shear cracks with damage zones are related to fault formation and growth, and earthquake rupture physics and size, but observational and analytical limitations impede use of the shear crack paradigm in quantitative, monitoring and hazard seismology. Here we obtain high-precision earthquake relocations for the 2020 M6.5 Monte Cristo Range, Nevada earthquake sequence. The seismicity illuminates two, en-echelon primary faulting surfaces and surrounding, characteristic shear-crack features such as edge, wall, tip, and linking damage zones, showing that this sequence ruptured a complete shear crack system. Shallow damage zones align with areas of dense surface fracturing, subsidence and after-slip, showing the importance of damage zones for shaking intensity and earthquake hazard. These results emphasize the importance of using the complete shear crack model in earthquake seismology.