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Location:
60 km ENE of Cantwell, Alaska
Period:
2 Nov 2002 08:41:23 - 6 Mar 2003 04:13:31 (123 days 19 hours 32 minutes)
Volcanoes in 100km radius:
Buzzard Creek(86km)
Earthquakes:
7093
M 7.0+:
M 7.9; 2002 Denali Fault, Alaska Earthquake; (3 Nov 2002) (14km from the swarm center)
26 swarms found nearby.
2002
3 Nov
19 days 3 hours
621 earthquakes
7 Nov
1 day 2 hours
42 earthquakes
10 Nov
1 day 16 hours
49 earthquakes
S20021113.1(24.8km)
12 Nov
1 day 14 hours
71 earthquakes
S20021124.1(19.5km)
23 Nov
16 days 18 hours
425 earthquakes
24 Nov
3 days 20 hours
81 earthquakes
25 Nov
1 day 2 hours
30 earthquakes
30 Nov
6 days 3 hours
158 earthquakes
6 Dec
20 days 21 hours
548 earthquakes
10 Dec
4 days 4 hours
122 earthquakes
18 Dec
1 day 16 hours
36 earthquakes
20 Dec
3 days 6 hours
135 earthquakes
S20021225.1(28.6km)
24 Dec
5 days 15 hours
113 earthquakes
S20021229.1(10.9km)
28 Dec
9 days 5 hours
191 earthquakes
2003
1 Jan
2 days 1 hours
49 earthquakes
S20030107.1(26.6km)
6 Jan
4 days 21 hours
72 earthquakes
11 Jan
2 days 21 hours
45 earthquakes
2 Feb
3 days 0 hours
42 earthquakes
22 Feb
1 day 14 hours
31 earthquakes
15 Mar
1 day 20 hours
37 earthquakes
S20030602.2(24.7km)
1 Jun
11 days 13 hours
108 earthquakes
S20030714.1(27.0km)
13 Jul
20 days 18 hours
166 earthquakes
S20030910.1(11.3km)
9 Sep
2 days 8 hours
35 earthquakes
S20031210.1(16.5km)
9 Dec
10 days 20 hours
147 earthquakes
2004
S20040129.1(23.4km)
28 Jan
3 days 8 hours
47 earthquakes
2006
S20061005.1(13.4km)
4 Oct
16 hours
26 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20021103.1 Near Cantwell, Alaska

The seismic swarm designated S20021103.1 occurred approximately 60 km east-northeast of Cantwell, Alaska, within the Denali Fault zone. It began at 08:41 UTC on 2 November 2002 and concluded at 04:13 UTC on 6 March 2003, spanning 2,971 hours and 32 minutes. During this period, 7,093 earthquakes were recorded, reflecting intense localized crustal activity.

Analysis of the first 100 events reveals predominantly shallow hypocenters, with depths ranging from 0 km to 20 km and a median near 5 km. Magnitudes varied from 0.2 to 5.1, with the majority below 3.0 and several events exceeding 4.0, including peaks of 5.0 and 5.1. Early activity on 2 November featured low-magnitude events clustered at depths under 10 km, transitioning to a sequence of stronger shocks on 3 November that included multiple events between 3.0 and 4.9. Subsequent events through 4 November maintained similar depth distributions while showing a gradual decline in peak magnitudes.

This swarm unfolded in close proximity to the magnitude 7.9 Denali Fault earthquake of 3 November 2002, whose epicenter lay 14 km from the swarm centroid. The timing suggests possible interaction between the mainshock rupture and the ongoing swarm sequence, consistent with stress redistribution along strike-slip faults in the region.

The Denali Fault represents a major right-lateral strike-slip structure within the broader tectonic framework of south-central Alaska. This area experiences high seismicity due to oblique convergence between the Pacific and North American plates, accommodated partly by the fault system and associated subsidiary structures. Historical records indicate recurrent large-magnitude events along the Denali Fault, underscoring its role in regional deformation.

Post-2002 monitoring has confirmed continued low-level activity in the vicinity, though no comparable swarms have been documented at the same intensity. The shallow nature of the recorded events aligns with the brittle upper crust characteristic of the fault zone, where most strain release occurs at depths less than 15 km.

References
SeismoSight internal swarm classification S20021103.1
USGS Earthquake Hazards Program records for the 2002 Denali Fault earthquake