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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:
11 km ENE of Hebgen Lake Estates, Montana
Period:
8 Dec 2001 19:08:02 - 28 Dec 2001 00:54:59 (19 days 5 hours 46 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
335
91 swarms found nearby.
2000
25 Jan
1 day 8 hours
67 earthquakes
29 Mar
9 days 3 hours
185 earthquakes
8 Apr
1 day 23 hours
41 earthquakes
S20000526.1(25.7km)
26 May
23 hours
25 earthquakes
S20000728.1(22.9km)
27 Jul
5 days 11 hours
144 earthquakes
25 Oct
2 days 15 hours
52 earthquakes
S20001124.1(22.5km)
23 Nov
3 days 8 hours
120 earthquakes
S20001210.1(26.7km)
9 Dec
1 day 1 hours
29 earthquakes
S20001224.1(17.8km)
23 Dec
4 days 11 hours
64 earthquakes
2001
S20010119.1(13.5km)
18 Jan
4 days 18 hours
341 earthquakes
26 Feb
2 days 5 hours
56 earthquakes
2 Dec
5 days 0 hours
131 earthquakes
2002
30 Jan
2 days 22 hours
52 earthquakes
S20021104.1(13.2km)
3 Nov
4 days 4 hours
118 earthquakes
3 Nov
3 days 12 hours
80 earthquakes
5 Dec
2 days 12 hours
405 earthquakes
13 Dec
1 day 12 hours
26 earthquakes
2003
S20030103.2(25.2km)
3 Jan
4 days 3 hours
75 earthquakes
S20030131.1(26.5km)
31 Jan
1 day 15 hours
36 earthquakes
5 Feb
1 day 18 hours
42 earthquakes
2004
13 Apr
6 days 22 hours
457 earthquakes
16 Jul
1 day 16 hours
38 earthquakes
2005
3 Jun
2 days 8 hours
49 earthquakes
2006
S20060222.1(27.2km)
22 Feb
15 hours
44 earthquakes
S20060613.1(22.9km)
12 Jun
1 day 14 hours
45 earthquakes
18 Jun
1 day 11 hours
57 earthquakes
S20061015.1(26.7km)
14 Oct
19 hours
79 earthquakes
2007
S20070620.1(20.4km)
20 Jun
1 hours
26 earthquakes
14 Dec
22 hours
28 earthquakes
S20071231.1(10.4km)
30 Dec
3 days 10 hours
61 earthquakes
2008
9 Jan
4 days 20 hours
89 earthquakes
S20080203.1(20.5km)
3 Feb
21 hours
47 earthquakes
S20080311.1(27.0km)
11 Mar
2 days 13 hours
69 earthquakes
S20080729.1(24.1km)
28 Jul
4 days 18 hours
189 earthquakes
S20080807.1(17.0km)
7 Aug
6 hours
32 earthquakes
3 Dec
6 days 17 hours
213 earthquakes
2009
16 Apr
5 days 18 hours
136 earthquakes
S20090525.1(26.7km)
25 May
10 hours
70 earthquakes
S20090630.1(21.7km)
30 Jun
1 day 12 hours
34 earthquakes
12 Sep
21 hours
24 earthquakes
16 Sep
1 day 7 hours
28 earthquakes
2010
S20100117.1(22.6km)
16 Jan
19 days 8 hours
2268 earthquakes
2011
3 May
1 day 22 hours
33 earthquakes
2013
S20130507.1(21.7km)
7 May
22 hours
34 earthquakes
29 Jun
3 days 16 hours
79 earthquakes
S20130713.1(11.4km)
13 Jul
19 hours
30 earthquakes
13 Sep
4 days 4 hours
243 earthquakes
27 Sep
1 day 12 hours
28 earthquakes
S20131005.1(28.1km)
5 Oct
7 hours
54 earthquakes
23 Nov
6 days 16 hours
223 earthquakes
2014
S20140122.1(19.5km)
21 Jan
2 days 1 hours
46 earthquakes
S20140217.1(26.0km)
16 Feb
3 days 7 hours
52 earthquakes
S20140330.1(25.9km)
29 Mar
3 days 19 hours
194 earthquakes
S20140601.1(24.3km)
31 May
6 days 5 hours
232 earthquakes
S20140819.4(11.4km)
18 Aug
1 day 15 hours
42 earthquakes
20 Aug
1 day 4 hours
40 earthquakes
2015
21 Jan
1 day 8 hours
135 earthquakes
13 Oct
1 day 20 hours
31 earthquakes
7 Nov
1 day 23 hours
85 earthquakes
2016
24 Sep
1 day 16 hours
46 earthquakes
2017
12 Jun
45 days 12 hours
1542 earthquakes
1 Aug
17 days 7 hours
784 earthquakes
20 Aug
4 days 18 hours
43 earthquakes
27 Aug
3 days 8 hours
66 earthquakes
2018
15 Feb
11 days 1 hours
728 earthquakes
S20180725.1(22.1km)
24 Jul
2 days 20 hours
52 earthquakes
2019
S20190326.2(20.5km)
26 Mar
20 hours
29 earthquakes
S20191026.1(20.7km)
26 Oct
1 day 22 hours
83 earthquakes
2020
S20200219.1(21.7km)
18 Feb
2 days 20 hours
62 earthquakes
9 May
2 days 5 hours
80 earthquakes
S20200522.1(20.5km)
22 May
2 hours
36 earthquakes
S20200529.1(21.2km)
29 May
1 day 10 hours
88 earthquakes
2021
21 Jun
1 day 13 hours
117 earthquakes
27 Jun
5 days 17 hours
230 earthquakes
16 Sep
4 days 0 hours
75 earthquakes
30 Sep
1 day 16 hours
62 earthquakes
2022
S20220329.1(11.7km)
28 Mar
2 days 12 hours
117 earthquakes
S20220611.1(21.3km)
10 Jun
2 days 20 hours
62 earthquakes
S20220826.1(20.4km)
26 Aug
9 days 4 hours
198 earthquakes
S20220918.2(20.3km)
17 Sep
6 days 20 hours
389 earthquakes
S20220930.1(21.3km)
29 Sep
3 days 4 hours
53 earthquakes
S20221013.1(20.5km)
13 Oct
8 days 6 hours
111 earthquakes
S20221115.1(21.8km)
14 Nov
2 days 5 hours
48 earthquakes
2023
S20230207.2(10.5km)
6 Feb
2 days 9 hours
63 earthquakes
13 Mar
1 day 18 hours
136 earthquakes
S20231004.1(21.5km)
3 Oct
1 day 14 hours
39 earthquakes
2024
S20240106.1(10.3km)
6 Jan
10 hours
35 earthquakes
S20240218.1(21.9km)
18 Feb
9 hours
50 earthquakes
23 Apr
4 days 7 hours
79 earthquakes
2025
4 Mar
12 hours
25 earthquakes
7 May
8 hours
37 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20011209.3: Analysis of Activity Near Hebgen Lake, Montana

Seismic swarm S20011209.3 was recorded beginning at 19:08 on 8 December 2001 and concluding at 00:54 on 28 December 2001. The events were located 11 km east-northeast of Hebgen Lake Estates, Montana. Over 461 hours and 46 minutes, a total of 335 earthquakes were registered.

Analysis of the first 100 events reveals predominantly low-magnitude activity. The initial shock reached magnitude 3.1 at a depth of 7 km. Subsequent events clustered between magnitudes -0.4 and 2.1, with the large majority falling below magnitude 1.0. Depths ranged from 1 km to 13 km, centering most frequently around 6–8 km. A single outlier recorded at magnitude -9.9 appears within the sequence but does not alter the overall pattern of shallow microseismicity. The swarm displayed episodic bursts, with elevated rates during the evenings of 8–10 December and again around 13 December.

Hebgen Lake lies within the Intermountain Seismic Belt, a zone of active normal faulting that extends from Arizona into Montana. The region is influenced by Basin and Range extension and proximity to the Yellowstone volcanic system. The Hebgen Lake fault, a west-dipping normal fault, has produced significant historical earthquakes, most notably the magnitude 7.3 event of 17 August 1959. That quake triggered a massive landslide that dammed the Madison River and caused 28 fatalities, underscoring the area’s capacity for damaging seismicity.

Swarm activity in this setting is commonly attributed to fluid migration along pre-existing faults and regional tectonic stress. The 2001 sequence fits this pattern, with events concentrated at shallow crustal depths consistent with hydrothermal or magmatic influences from the nearby Yellowstone hotspot. Since 1 January 2000, twelve such swarms have been documented in the vicinity, including nine in 2000 and three in 2001, indicating recurrent episodic release of strain.

Ongoing monitoring by regional seismic networks continues to track microseismicity in the Hebgen Lake area. These observations contribute to refined hazard assessments for the northern Intermountain region, where both tectonic and volcanic processes remain active.

References

  • USGS Earthquake Hazards Program: Hebgen Lake, Montana historical seismicity
  • Montana Bureau of Mines and Geology: Regional fault maps and swarm catalogs
  • University of Utah Seismograph Stations: Intermountain Seismic Belt reports