The Fallon cluster is named for the town of Fallon in western Nevada,
U.S.A. The cluster includes two recent sequences headed by
moderate-sized events, the 5.8 Mw Parker Butte earthquake on December 9,
2024 and a 5.7 Mw event on April 14, 2026 about 18 km north-northwest,
near Silver Springs. The cluster covers a considerably larger area than
these two sequences, mainly to the northeast because this region was the
site of a series of magnitude 6 and 7 earthquakes in 1954 and 1959. The
attempt to include these important earthquakes in the calibrated cluster
was ultimately abandoned due to the poor connectivity with the modern
seismicity. In the 1950s there were very few seismograph stations at
local or near-regional distances and most of them are no longer
operating. With the exception of the two recent moderate-sized events,
most of the remaining events in the cluster are less than magnitude 4
and have few readings beyond regional distances, so the overlap of
observing stations between the older large earthquakes and modern
lower-magnitude seismicity is very scant: around a dozen stations in
common, `even for the largest event, the December 16, 1954 Fairview Peak
earthquake (7.1 Mw). Station distribution for location calibration is
very good. All events have depth control from near-source or
local-distance readings.
