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Location:
23 km E of Honaunau-Napoopoo, Hawaii
Period:
23 Jul 2015 18:45:01 - 24 Jul 2015 18:26:07 (23 hours 41 minutes)
Volcanoes in 100km radius:
Mauna Loa(3km), Hualalai(33km), Kilauea(37km), Mauna Kea(41km), Kama'ehuakanaloa(73km)
Earthquakes:
34
20 swarms found nearby.
2004
28 Aug
24 days 12 hours
397 earthquakes
11 Oct
19 days 12 hours
360 earthquakes
VS20041110.1(13.5km)
9 Nov
24 days 3 hours
334 earthquakes
14 Dec
15 days 10 hours
342 earthquakes
2006
VS20060312.1(25.9km)
11 Mar
3 days 5 hours
41 earthquakes
2015
1 May
6 days 18 hours
118 earthquakes
2016
3 Jul
6 days 16 hours
84 earthquakes
2017
7 Apr
4 days 14 hours
129 earthquakes
15 Apr
1 day 20 hours
56 earthquakes
2020
S20200302.1(20.9km)
1 Mar
4 days 18 hours
82 earthquakes
4 Dec
5 days 13 hours
110 earthquakes
2021
28 Feb
4 days 16 hours
47 earthquakes
S20210318.1(23.7km)
18 Mar
2 days 15 hours
113 earthquakes
29 Mar
8 days 10 hours
279 earthquakes
7 Apr
12 days 0 hours
300 earthquakes
2022
3 Feb
5 days 5 hours
170 earthquakes
2 Aug
3 days 9 hours
131 earthquakes
23 Sep
14 days 19 hours
375 earthquakes
VS20221128.1(12.1km)
27 Nov
11 days 2 hours
416 earthquakes
2026
S20260524.2(29.8km)
23 May
1 day 8 hours
26 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm VS20150724.1: Analysis of Activity Near Honaunau-Napoopoo, Hawaii

A seismic swarm designated VS20150724.1 occurred 23 km east of Honaunau-Napoopoo on the Island of Hawaii. The sequence began at 18:45 UTC on 23 July 2015 and concluded at 18:26 UTC on 24 July 2015, spanning 23 hours and 41 minutes. During this interval, 34 earthquakes were recorded.

Magnitudes ranged from 0.6 to 2.3, with the majority of events below 1.0. Depths varied between 0 and 14 km, indicating predominantly shallow seismicity. Notable events included a magnitude 2.3 earthquake at 08:21 UTC on 24 July at 4 km depth and a magnitude 2.2 event at 13:09 UTC on the same day at 3 km depth. The initial event registered magnitude 1.0 at 10 km depth, while several later shocks clustered at depths of 4–5 km.

This swarm represents the sixth such sequence recorded in the region since 1 January 2000. Earlier swarms occurred in 2004 (four events), 2006 (one event), and one prior instance in 2015.

The Honaunau-Napoopoo area lies on the western flank of the Big Island, within the tectonically active zone influenced by Hawaii’s hotspot volcanism. The underlying geology consists of layered basaltic lava flows from Mauna Loa and Kilauea volcanoes, punctuated by normal faults and rift zones. Seismicity in this setting commonly arises from magma intrusion, volcanic flank movement, or adjustment along pre-existing fractures. Depths observed in the swarm align with typical crustal levels where such processes occur.

Hawaii’s volcanic history spans millions of years, with the current island edifice built over the past 500,000 years. Ongoing monitoring by the U.S. Geological Survey documents frequent low-magnitude earthquake clusters linked to the islands’ dynamic subsurface environment. The 2015 swarm fits within this established pattern of episodic, shallow seismic activity.

References

  • U.S. Geological Survey Earthquake Hazards Program
  • Hawaiian Volcano Observatory Geological Summaries