DashboardNewsSwarmsM 7.0+
VolcanoesSupervolcanoesRegionsGlobal
Favorites
BlogAbout
Privacy PolicyDisclaimer
Follow
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:
39 km ESE of Mina, Nevada
Period:
19 Oct 2020 19:34:42 - 21 Oct 2020 19:32:52 (1 day 23 hours 58 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
31
17 swarms found nearby.
2003
S20030529.1(17.5km)
29 May
4 days 7 hours
164 earthquakes
S20031116.1(11.9km)
15 Nov
2 days 1 hours
52 earthquakes
2013
S20130120.1(22.9km)
19 Jan
2 days 18 hours
65 earthquakes
2020
S20200515.1(13.9km)
15 May
295 days 1 hours
21711 earthquakes
S20200516.2(26.4km)
15 May
22 hours
26 earthquakes
16 May
11 days 1 hours
418 earthquakes
S20200528.1(26.5km)
27 May
17 days 11 hours
384 earthquakes
S20200615.1(29.9km)
14 Jun
31 days 0 hours
472 earthquakes
2 Dec
8 days 6 hours
153 earthquakes
19 Dec
7 days 21 hours
133 earthquakes
2021
29 Mar
19 days 16 hours
285 earthquakes
S20210505.1(11.9km)
4 May
16 days 21 hours
229 earthquakes
S20210927.1(12.5km)
26 Sep
2 days 0 hours
31 earthquakes
S20211001.1(14.4km)
30 Sep
6 days 14 hours
87 earthquakes
S20211016.1(19.2km)
15 Oct
7 days 7 hours
86 earthquakes
S20211029.1(21.1km)
28 Oct
10 days 4 hours
136 earthquakes
2022
S20220105.1(11.7km)
4 Jan
6 days 14 hours
106 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20201020.3: Analysis of Activity Near Mina, Nevada

Seismic swarm S20201020.3 was recorded in the area 39 km east-southeast of Mina, Nevada, between 19 October 2020 at 19:34 UTC and 21 October 2020 at 19:32 UTC. Over this 47-hour-58-minute period, a total of 31 earthquakes were detected. Magnitudes ranged from 0.6 to 3.3, with the largest event occurring on 20 October at 11:51:55 UTC. Depths remained shallow, generally between 0 and 12 km, consistent with activity along upper-crustal faults in the region.

The sequence began with two small events on 19 October (magnitudes 1.2 and 1.1). Activity intensified on 20 October, producing 24 events within roughly 12 hours, including the peak magnitude-3.3 shock. Subsequent events tapered off, with only five additional earthquakes registered before the swarm concluded on 21 October. Most events clustered between 7 and 10 km depth, although a few occurred at shallower levels near 1–2 km or deeper near 12 km. This temporal pattern—rapid onset followed by gradual decay without a single dominant mainshock—is characteristic of swarm behavior rather than a classic foreshock–mainshock–aftershock sequence.

The Mina region lies within the Walker Lane belt of western Nevada, a zone of distributed dextral shear and extension that accommodates a significant fraction of Pacific–North America plate motion. The local geology is dominated by Basin and Range normal faulting superimposed on earlier Mesozoic and Cenozoic structures. Quaternary faults in the Excelsior Mountains and surrounding valleys exhibit evidence of Holocene displacement, placing the area within a moderately active seismic corridor. Historical records show that Mineral County has experienced notable earthquakes, including the 1932 Cedar Mountain event (magnitude 7.2) approximately 50 km to the northeast.

Since 2000, eight swarms have been documented in the immediate vicinity. Earlier episodes occurred in 2003 (two swarms) and 2013 (one swarm). The 2020 calendar year alone accounted for five swarms, indicating a temporary increase in swarm frequency. Such clustering is common in the Walker Lane, where fluid migration and aseismic slip on fault networks can trigger episodic earthquake sequences without producing large-magnitude events.

The shallow focal depths observed during swarm S20201020.3 align with the brittle–ductile transition zone expected in this extensional tectonic setting. No damage or felt reports of significance were associated with the sequence, reflecting the modest magnitudes involved. Continued monitoring by regional seismic networks remains important for tracking potential changes in swarm rate that could signal evolving stress conditions along nearby faults.

References

  • U.S. Geological Survey Earthquake Catalog (ANSS Comprehensive Catalog)
  • Nevada Seismological Laboratory swarm database
  • USGS Quaternary Fault and Fold Database of the United States
  • Nevada Bureau of Mines and Geology geologic maps of Mineral County