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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:
29 km E of West Yellowstone, Montana
Period:
4 Oct 2021 14:21:12 - 5 Oct 2021 14:59:01 (1 day 37 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
41
73 swarms found nearby.
2000
S20000125.1(29.1km)
25 Jan
1 day 8 hours
67 earthquakes
9 Mar
9 hours
28 earthquakes
S20000329.2(28.1km)
29 Mar
9 days 3 hours
185 earthquakes
S20000409.1(28.3km)
8 Apr
1 day 23 hours
41 earthquakes
26 May
23 hours
25 earthquakes
S20000728.1(11.9km)
27 Jul
5 days 11 hours
144 earthquakes
S20001124.1(11.2km)
23 Nov
3 days 8 hours
120 earthquakes
9 Dec
1 day 1 hours
29 earthquakes
S20001224.1(14.6km)
23 Dec
4 days 11 hours
64 earthquakes
2001
3 Feb
15 hours
26 earthquakes
S20010227.1(27.9km)
26 Feb
2 days 5 hours
56 earthquakes
2002
15 Jan
7 hours
67 earthquakes
S20020130.2(24.9km)
30 Jan
2 days 22 hours
52 earthquakes
S20021104.1(28.7km)
3 Nov
4 days 4 hours
118 earthquakes
S20021205.1(24.5km)
5 Dec
2 days 12 hours
405 earthquakes
S20021214.1(26.8km)
13 Dec
1 day 12 hours
26 earthquakes
2004
S20040413.1(22.7km)
13 Apr
6 days 22 hours
457 earthquakes
2006
S20060613.1(27.4km)
12 Jun
1 day 14 hours
45 earthquakes
S20060618.1(29.7km)
18 Jun
1 day 11 hours
57 earthquakes
10 Jul
5 hours
35 earthquakes
2007
S20070620.1(12.8km)
20 Jun
1 hours
26 earthquakes
S20071231.1(22.1km)
30 Dec
3 days 10 hours
61 earthquakes
2008
S20080109.1(22.9km)
9 Jan
4 days 20 hours
89 earthquakes
S20080126.1(27.4km)
25 Jan
12 hours
33 earthquakes
S20080203.1(12.1km)
3 Feb
21 hours
47 earthquakes
S20080311.1(28.9km)
11 Mar
2 days 13 hours
69 earthquakes
S20080807.1(15.4km)
7 Aug
6 hours
32 earthquakes
2009
S20090525.1(21.9km)
25 May
10 hours
70 earthquakes
S20090630.1(10.8km)
30 Jun
1 day 12 hours
34 earthquakes
2013
S20130713.1(21.8km)
13 Jul
19 hours
30 earthquakes
13 Sep
4 days 4 hours
243 earthquakes
S20131005.1(26.0km)
5 Oct
7 hours
54 earthquakes
2014
S20140122.1(13.4km)
21 Jan
2 days 1 hours
46 earthquakes
11 Feb
3 days 20 hours
69 earthquakes
16 Feb
3 days 7 hours
52 earthquakes
29 Mar
3 days 19 hours
194 earthquakes
31 May
6 days 5 hours
232 earthquakes
6 Jul
12 hours
46 earthquakes
2017
14 Aug
22 hours
32 earthquakes
S20170827.1(29.7km)
27 Aug
3 days 8 hours
66 earthquakes
2018
S20180216.1(26.1km)
15 Feb
11 days 1 hours
728 earthquakes
11 Mar
7 hours
28 earthquakes
S20180725.1(10.3km)
24 Jul
2 days 20 hours
52 earthquakes
31 Dec
4 hours
57 earthquakes
2019
S20190326.2(12.3km)
26 Mar
20 hours
29 earthquakes
22 Jul
3 days 7 hours
61 earthquakes
S20191026.1(11.6km)
26 Oct
1 day 22 hours
83 earthquakes
2020
S20200219.1(11.0km)
18 Feb
2 days 20 hours
62 earthquakes
S20200509.3(27.6km)
9 May
2 days 5 hours
80 earthquakes
S20200522.1(12.4km)
22 May
2 hours
36 earthquakes
S20200529.1(11.6km)
29 May
1 day 10 hours
88 earthquakes
6 Dec
1 day 7 hours
37 earthquakes
24 Dec
12 hours
47 earthquakes
2021
21 Jun
1 day 13 hours
117 earthquakes
16 Sep
4 days 0 hours
75 earthquakes
27 Sep
7 hours
26 earthquakes
30 Sep
1 day 16 hours
62 earthquakes
25 Nov
2 days 12 hours
61 earthquakes
2022
S20220329.1(20.6km)
28 Mar
2 days 12 hours
117 earthquakes
S20220611.1(12.0km)
10 Jun
2 days 20 hours
62 earthquakes
S20220826.1(12.7km)
26 Aug
9 days 4 hours
198 earthquakes
5 Sep
3 hours
40 earthquakes
S20220918.2(13.1km)
17 Sep
6 days 20 hours
389 earthquakes
S20220930.1(11.7km)
29 Sep
3 days 4 hours
53 earthquakes
5 Oct
1 day 8 hours
32 earthquakes
S20221013.1(12.6km)
13 Oct
8 days 6 hours
111 earthquakes
S20221115.1(12.3km)
14 Nov
2 days 5 hours
48 earthquakes
2023
S20230207.2(23.0km)
6 Feb
2 days 9 hours
63 earthquakes
S20231004.1(11.1km)
3 Oct
1 day 14 hours
39 earthquakes
2024
1 Jan
1 day 16 hours
47 earthquakes
3 Jan
1 day 15 hours
62 earthquakes
S20240106.1(22.7km)
6 Jan
10 hours
35 earthquakes
S20240218.1(10.4km)
18 Feb
9 hours
50 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20211005.1: Analysis of Activity East of West Yellowstone, Montana

Seismic swarm S20211005.1 occurred approximately 29 km east of West Yellowstone, Montana, within the tectonically active Yellowstone region. The event sequence began at 14:21 on 4 October 2021 and concluded at 14:59 on 5 October 2021, encompassing 41 earthquakes over 24 hours and 37 minutes. This swarm reflects typical background seismicity driven by the underlying Yellowstone hotspot and associated caldera system, where magmatic fluids and regional faulting interact to produce clustered events.

The earthquakes exhibited low magnitudes, with the largest reaching 2.6. Depths ranged primarily between 2 km and 8 km, consistent with shallow crustal processes in the area. Early activity on 4 October included multiple events above magnitude 2.0 clustered around 22:00–23:00, followed by a peak event of 2.6 at 00:30 on 5 October. Later phases showed diminishing energy release, with many events below magnitude 1.0. Such patterns indicate fluid migration or stress redistribution along pre-existing faults rather than a single mainshock-aftershock sequence.

Yellowstone lies above a continental hotspot that has produced voluminous volcanism over millions of years. The current caldera, formed approximately 631,000 years ago during the Lava Creek eruption, remains a locus of deformation and seismicity. Earthquake swarms here arise from hydrothermal circulation, dike intrusion, and normal faulting within the Basin and Range province. Since 2000, 57 swarms have been documented in the broader region, with notable yearly counts including 9 in 2000, 6 each in 2014 and 2020, and 4 in 2021. These recurrent swarms underscore the persistent, low-level volcanic-tectonic unrest characteristic of the area.

No surface deformation or changes in hydrothermal features were associated with this particular swarm, aligning with the modest energy release observed. Monitoring by regional networks continues to track such episodes to refine understanding of magma-hydrothermal dynamics beneath the Yellowstone Plateau.

References

USGS Earthquake Catalog
Yellowstone Volcano Observatory reports