Location:

Period:

2 Dec 2020 05:53:31 - 10 Dec 2020 12:10:01 (8 days 6 hours 16 minutes)

Volcanoes in 100km radius:

None

Earthquakes:

153

17 swarms found nearby.

2003

S20030529.1(15.7km)

29 May

4 days 7 hours

164 earthquakes

S20031116.1(10.2km)

15 Nov

2 days 1 hours

52 earthquakes

2013

S20130120.1(21.6km)

19 Jan

2 days 18 hours

65 earthquakes

2020

S20200515.1(12.6km)

15 May

295 days 1 hours

21711 earthquakes

S20200516.2(25.0km)

15 May

22 hours

26 earthquakes

S20200517.1(3.0km)

16 May

11 days 1 hours

418 earthquakes

S20200528.1(25.0km)

27 May

17 days 11 hours

384 earthquakes

S20200615.1(28.6km)

14 Jun

31 days 0 hours

472 earthquakes

S20201020.3(1.8km)

19 Oct

1 day 23 hours

31 earthquakes

S20201220.1(6.2km)

19 Dec

7 days 21 hours

133 earthquakes

2021

S20210330.1(7.5km)

29 Mar

19 days 16 hours

285 earthquakes

S20210505.1(10.8km)

4 May

16 days 21 hours

229 earthquakes

S20210927.1(11.3km)

26 Sep

2 days 0 hours

31 earthquakes

S20211001.1(13.1km)

30 Sep

6 days 14 hours

87 earthquakes

S20211016.1(17.9km)

15 Oct

7 days 7 hours

86 earthquakes

S20211029.1(19.8km)

28 Oct

10 days 4 hours

136 earthquakes

2022

S20220105.1(10.3km)

4 Jan

6 days 14 hours

106 earthquakes

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Seismic Swarm S20201203.1 Near Mina, Nevada

A notable earthquake swarm designated S20201203.1 occurred 35 km southeast of Mina, Nevada, in the western Great Basin. The sequence began at 05:53 UTC on 2 December 2020 and concluded at 12:10 UTC on 10 December 2020, spanning 198 hours and 16 minutes. During this period, 153 earthquakes were recorded.

The swarm unfolded in the tectonically active Walker Lane belt, a northwest-trending zone of dextral shear accommodating roughly 20 percent of Pacific-North America plate motion. This region features a network of normal and strike-slip faults superimposed on Basin and Range extension. Seismicity here is common, driven by ongoing crustal deformation along structures such as the Mina deflection and nearby segments of the Walker Lane.

Analysis of the first 100 events reveals magnitudes ranging from 0.4 to 4.0, with most events clustered between 0.8 and 2.5. Depths predominantly fell between 3 km and 13 km, consistent with shallow crustal faulting typical of the area. The largest event, magnitude 4.0, occurred at 03:18 UTC on 3 December at a depth of 4 km, followed within minutes by a magnitude 3.0 shock. Subsequent activity included multiple events above magnitude 2.5 on 4–6 December, though none exceeded the initial peak. Shallow depths under 5 km characterized several early larger shocks, while later events showed slightly greater average depths around 8–10 km.

Historical records maintained by SeismoSight indicate nine swarms have occurred in the same locale since 1 January 2000. These include two events in 2003, one in 2013, and six in 2020, underscoring episodic swarm behavior rather than isolated mainshock-aftershock sequences. Such patterns align with fluid migration or aseismic slip triggering along distributed faults in the Walker Lane.

The December 2020 swarm fits this established regional style, with rapid onset, high event rates in the first 48 hours, and gradual decay. No damage or felt reports beyond light shaking were associated with the largest events, reflecting their modest magnitudes and rural setting.

References

USGS Earthquake Catalog (earthquake.usgs.gov)
Nevada Seismological Laboratory regional reports
SeismoSight internal swarm classification database