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:
57 km SE of West Yellowstone, Montana
Period:
14 Oct 2009 07:31:46 - 18 Oct 2009 07:01:13 (3 days 23 hours 29 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
138
32 swarms found nearby.
2002
8 Oct
3 days 11 hours
120 earthquakes
3 Nov
2 days 6 hours
67 earthquakes
3 Nov
1 day 2 hours
25 earthquakes
10 Nov
15 hours
30 earthquakes
5 Dec
1 day 6 hours
39 earthquakes
2004
31 Aug
1 day 10 hours
27 earthquakes
2006
18 Mar
12 hours
28 earthquakes
5 Apr
16 hours
77 earthquakes
2008
23 Nov
1 day 15 hours
66 earthquakes
27 Dec
8 days 7 hours
823 earthquakes
2009
14 Sep
2 days 16 hours
39 earthquakes
17 Sep
19 hours
25 earthquakes
2010
12 Jun
22 hours
28 earthquakes
2011
14 Apr
7 hours
24 earthquakes
2013
6 Jan
1 day 14 hours
54 earthquakes
15 Apr
17 hours
30 earthquakes
23 Jun
5 hours
29 earthquakes
2015
4 Sep
4 hours
24 earthquakes
2016
24 Nov
1 day 13 hours
60 earthquakes
2018
11 Apr
1 day 0 hours
114 earthquakes
31 Dec
4 hours
57 earthquakes
2019
29 Aug
14 hours
43 earthquakes
2020
12 Feb
11 hours
36 earthquakes
10 Sep
2 days 23 hours
117 earthquakes
1 Dec
2 days 8 hours
114 earthquakes
6 Dec
1 day 7 hours
37 earthquakes
2021
15 Jul
7 days 4 hours
820 earthquakes
2022
12 Feb
7 hours
25 earthquakes
2 Mar
1 day 22 hours
33 earthquakes
2023
29 Mar
2 days 6 hours
110 earthquakes
16 Apr
1 day 20 hours
38 earthquakes
24 Apr
6 hours
31 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm SVS20091015.1: Analysis of Activity Southeast of West Yellowstone, Montana

An earthquake swarm designated SVS20091015.1 occurred southeast of West Yellowstone, Montana, from 07:31 on 14 October 2009 to 07:01 on 18 October 2009. The sequence lasted 95 hours and 29 minutes and produced 138 events. The epicentral area lies approximately 57 km southeast of West Yellowstone within the tectonically active Yellowstone volcanic region.

Analysis of the first 100 recorded events reveals predominantly low-magnitude seismicity. Magnitudes ranged from 0.1 to 2.2, with the majority falling between 0.5 and 1.7. Depths clustered between 1 km and 9 km, indicating shallow crustal sources typical of the area. Several events registered at 2.2, including those at 02:36, 03:22, 03:32, and 04:00 on 15 October. Isolated readings of -9.9 likely represent data artifacts rather than true magnitudes. The temporal distribution showed peak activity during the first 24 hours, followed by a gradual decline.

The Yellowstone Plateau occupies the northeastern margin of the Basin and Range Province and overlies a continental hotspot. This setting produces frequent earthquake swarms driven by fluid migration, hydrothermal circulation, and minor magmatic movement beneath the 640,000-year-old caldera. Regional faults accommodate extension and interact with the volcanic system, resulting in episodic seismic clusters rather than mainshock-aftershock sequences.

Historical records indicate 12 swarms in the region since 1 January 2000. Earlier episodes occurred in 2002 (5 swarms), 2004 (1 swarm), 2006 (2 swarms), 2008 (2 swarms), and 2009 (2 swarms). These events underscore the persistent seismic character of the Yellowstone volcanic field.

The SVS20091015.1 swarm fits established patterns of short-duration, low-magnitude activity without significant surface deformation or volcanic unrest. Continued monitoring remains essential given the area's dynamic geology.

References

USGS Earthquake Catalog (earthquake.usgs.gov)
Yellowstone Volcano Observatory Annual Reports
Smith RB, et al. (2009) Journal of Volcanology and Geothermal Research
SeismoSight internal swarm classification records