Field Response And Surface-Rupture Characteristics Of The 2020 M 6.5 Monte Cristo Range Earthquake, Central Walker Lane, Nevada

The M 6.5 Monte Cristo Range earthquake that occurred in the central Walker Lane on 15 May 2020 was the largest earthquake in Nevada in 66 yr and resulted in a multidis-ciplinary scientific field response. The earthquake was the result of left-lateral slip along largely unmapped parts of the Candelaria fault, one of a series of east?northeast-strik-ing faults that comprise the Mina deflection, a major right step in the north?northwest structural grain of the central Walker Lane. We describe the characteristics of the sur-face rupture and document distinct differences in the style and orientation of fractures produced along the 28 km long rupture zone. Along the western part of the rupture, left-lateral and extensional displacements occurred along northeasterly and north-strik-ing planes that splay off the eastern termination of the mapped Candelaria fault. To the east, extensional and right-lateral displacements occurred along predominantly north-striking planes that project toward well-defined Quaternary and bedrock faults. Although, the largest left-lateral displacement observed was similar to 20 cm, the majority of displacements were < 5 cm and were distributed across broad zones up to 800 m wide, which are not likely to be preserved in the geologic record. The complex pattern of sur-face rupture is consistent with a network of faults defined in the shallow subsurface by aftershock seismicity and suggests that slip partitioning between east-striking left-lat-eral faults and north to northwest-striking right-lateral faults plays an important role in accommodating northwest-directed transtension in the central Walker Lane.