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Note:This page contains AI-generated content for informational and entertainment purposes only. It may contain inaccuracies. Raw event data is from USGS and EMSC. All statistics, lists, and derived information are generated by this site. Full disclaimerFound an error?
Location:
25 km NW of Benton, California
Period:
19 Oct 2017 06:41:38 - 21 Oct 2017 20:31:10 (2 days 13 hours 49 minutes)
Volcanoes in 100km radius:
Mono Lake Volcanic Field(25km), Mono-Inyo Craters(34km), Mammoth Mountain(49km)
Earthquakes:
33
20 swarms found nearby.
2001
S20010308.1(25.5km)
7 Mar
2 days 6 hours
47 earthquakes
20 Mar
6 days 14 hours
96 earthquakes
2004
S20040918.1(13.1km)
17 Sep
67 days 17 hours
4783 earthquakes
13 Dec
15 days 7 hours
237 earthquakes
2006
S20060505.1(23.5km)
5 May
1 day 14 hours
30 earthquakes
2008
15 Jan
2 days 10 hours
50 earthquakes
1 Feb
2 days 6 hours
54 earthquakes
2009
S20090831.1(11.7km)
30 Aug
2 days 4 hours
34 earthquakes
2011
S20110704.1(27.0km)
3 Jul
3 days 20 hours
49 earthquakes
2015
4 May
2 days 22 hours
111 earthquakes
9 May
2 days 3 hours
35 earthquakes
2016
S20160805.1(28.2km)
4 Aug
5 days 7 hours
205 earthquakes
S20161228.1(26.9km)
28 Dec
58 days 12 hours
4521 earthquakes
2017
S20171009.1(28.1km)
8 Oct
3 days 3 hours
371 earthquakes
15 Oct
16 hours
26 earthquakes
2018
S20180207.1(26.9km)
7 Feb
2 days 14 hours
56 earthquakes
S20181207.1(14.2km)
7 Dec
1 day 2 hours
33 earthquakes
S20181217.1(14.1km)
17 Dec
2 days 9 hours
44 earthquakes
2020
11 Apr
33 days 8 hours
1019 earthquakes
2021
S20210115.1(19.4km)
15 Jan
1 day 14 hours
89 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20171020.1 Near Benton, California: Event Analysis and Regional Context

Seismic swarm S20171020.1 occurred 25 km northwest of Benton, California, in Mono County. The sequence began at 06:41 on 19 October 2017 and concluded at 20:31 on 21 October 2017, spanning 61 hours and 49 minutes. During this period, 33 earthquakes were recorded, with magnitudes ranging from 0.6 to 3.0 and depths between 0 and 15 km.

The swarm initiated with a magnitude 2.2 event at the surface, followed rapidly by smaller events at greater depths. Peak activity included a magnitude 3.0 quake at 4 km depth on 19 October at 07:44 and a magnitude 2.9 event at 1 km depth later that afternoon. Subsequent events showed a gradual decline in both frequency and magnitude, with the final recorded shock measuring 1.8 at 8 km depth.

This activity aligns with the broader tectonic setting of eastern California. The region lies within the Walker Lane belt, a zone of dextral shear and extension that accommodates a portion of Pacific-North American plate motion. Normal and strike-slip faulting predominates, producing frequent earthquake sequences in the Basin and Range province. Proximity to the Long Valley Caldera further contributes to elevated seismicity, as magmatic and hydrothermal processes interact with regional faults.

Historical records since 2000 indicate 15 prior swarms in the immediate area. These occurred in 2001 (two events), 2004 (two), 2006 (one), 2008 (two), 2009 (one), 2011 (one), 2015 (two), 2016 (two), and 2017 (two). Such recurrent swarms reflect ongoing crustal adjustment along active structures without evidence of a single large mainshock.

The 2017 sequence displayed typical swarm characteristics: a rapid onset, clustered timing, and absence of a dominant foreshock-mainshock-aftershock pattern. Depths remained shallow, consistent with brittle failure in the upper crust of this extensional environment.

References

  • SeismoSight internal swarm classification records
  • USGS Earthquake Catalog (historical swarm statistics, 2000–2017)
  • California Geological Survey, Regional Fault and Seismicity Maps