The February 9, 1934 earthquake

M5.5Excelsior Mountains, Nevada (Aftershock)

A magnitude 5.5 earthquake, centred in Mineral County. The 37th strongest in Nevada’s record since 1900, and the strongest within 50 miles since a magnitude 6.3 on January 30, 1934. 4 aftershocks of magnitude 2.5 or more followed within 30 days.

The earthquake

Magnitude
5.5
local magnitude (ml)
Depth
—
Not recorded
Local time
Friday, February 9, 1934
01:20 PST; 09:20 UTC
Epicentre
38.30°N, 118.40°W
In Mineral County
In Nevada’s record
37th
strongest of 8,110 since 1900
Within 50 miles
4
counties; more on this date

USGS ANSS Comprehensive Earthquake Catalog, event ushis1035 (“Excelsior Mountains, Nevada (Aftershock)”). The USGS event page carries the ShakeMap, felt reports and the official summary.

Aftershocks

Earthquakes of magnitude 2.5 or more within 20 miles of the epicentre in the 30 days after.

4

Aftershocks in 30 days

4.8

Largest aftershock, Feb 20, 1934

0

On the first day

1

In the 7 days before

Aftershocks of magnitude 2.5 or more, by day after the earthquake 1: 0 2: 1 1 3: 0 4: 1 5: 0 6: 0 7: 1 8: 0 9: 0 10: 0 11: 1 12: 0 13: 0 14: 0 15: 0 16: 0 17: 0 18: 0 19: 0 20: 0 21: 0 22: 0 23: 0 24: 0 25: 0 26: 0 27: 0 28: 0 29: 0 30: 0 1611162126
  1. The search radius is the surface rupture length expected for an earthquake of this magnitude (Wells and Coppersmith, 1994), at least 20 and at most 600 miles, so a great earthquake's sequence is counted along its whole fault.
  2. Before the modern seismic networks of the 1970s many small aftershocks went unrecorded, so early sequences read short.

Counties and cities within 50 miles

Distance from the epicentre to each county boundary (zero when inside) and to each city centre.

Counties

Earthquakes around the epicentre

1,645 earthquakes of magnitude 3 or more within 50 miles of this epicentre since 1973.

Earthquakes of magnitude 3 or more within 50 miles of the epicentre, by year 1973: 2 1974: 8 1975: 5 1976: 9 1977: 3 1978: 29 1979: 29 1980: 156 1981: 27 1982: 34 1983: 14 1984: 10 1985: 2 1986: 115 1987: 11 1988: 16 1989: 5 1990: 21 1991: 18 1992: 14 1993: 9 1994: 2 1995: 9 1996: 6 1997: 59 1998: 16 1999: 8 2000: 28 2001: 14 2002: 6 2003: 14 2004: 62 2005: 15 2006: 12 2007: 10 2008: 8 2009: 6 2010: 6 2011: 66 2012: 5 2013: 18 2014: 10 2015: 12 2016: 37 2017: 18 2018: 2 2019: 5 2020: 526 526 2021: 59 2022: 29 2023: 17 2024: 16 2025: 7 19731978198319881993199820032008201320182023

Earlier earthquakes of magnitude 5 or more within 50 miles, strongest first

USGS ANSS Comprehensive Earthquake Catalog. Local time is the time zone of the county nearest the epicentre. Magnitudes are as the catalogue reports them.