  On 15 May 2020 an MWW 6.5 earthquake occurred beneath the Monte Cristo Range
in the Mina Deflection region of western Nevada. Rapid deployment of eight
temporary seismic stations enables detailed analysis of its productive and
slowly decaying aftershock sequence (p=0.8) which included ~18,000 autodetected
events in 3.5 months. Double-difference, waveform-based relative relocation of
16,714 earthquakes reveals a complex network of faults, many of which cross the
inferred 35-km long east-northeast-striking, left-lateral mainshock rupture.
Seismicity aligns with left-lateral, right-lateral, and normal mechanism moment
tensors of 128 of the largest earthquakes. The mainshock occurred near the
middle of the aftershock zone at the intersection of two distinct zones of
seismicity. In the western section, numerous subparallel, shallow,
north-northeast-striking faults form a broad flower-structure-like fault mesh
that coalesces at depth into a near-vertical, left-lateral fault. We infer the
near-vertical fault to be a region of significant slip in the mainshock and an
eastward extension of the left-lateral Candelaria fault. Near the mainshock
hypocenter, seismicity occurs on a northeast-striking, west-dipping structure
which extends north from the Eastern Columbus Salt Marsh normal fault.
Together, these two intersecting structures bound the Columbus Salt Marsh
tectonic basin. East of this intersection and the mainshock hypocenter,
seismicity occurs in a narrow, near-vertical, east-northeast-striking fault
zone through to its eastern terminus. At the eastern end, the aftershock zone
broadens and extends northwest towards the southern extension of the
northwest-striking, right-lateral Petrified Springs fault system. The eastern
section hosts significantly fewer aftershocks than the western section, but has
more moment release.
