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Location:
Molucca Sea
Period:
1 Apr 2026 23:15:35 - 14 Apr 2026 18:05:29 (12 days 18 hours 49 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
397
16 swarms found nearby.
2001
PS20010225.1(12.8km)
24 Feb
16 hours
5 earthquakes
PS20010226.1(22.6km)
26 Feb
12 hours
5 earthquakes
PS20010827.1(23.1km)
26 Aug
1 day 19 hours
9 earthquakes
2007
PS20070121.1(36.0km)
21 Jan
3 days 13 hours
42 earthquakes
PS20070127.1(11.1km)
26 Jan
1 day 17 hours
7 earthquakes
2014
PS20141115.1(59.4km)
15 Nov
8 hours
8 earthquakes
PS20141126.1(64.1km)
25 Nov
1 day 0 hours
8 earthquakes
PS20141221.1(92.9km)
21 Dec
2 hours
5 earthquakes
2019
PS20190708.1(65.1km)
8 Jul
21 hours
5 earthquakes
PS20191114.1(27.9km)
14 Nov
1 day 7 hours
29 earthquakes
2026
PS20260402.1(29.7km)
1 Apr
2 days 2 hours
23 earthquakes
S20260402.4(22.7km)
1 Apr
11 days 20 hours
228 earthquakes
S20260402.3(16.4km)
2 Apr
5 days 1 hours
114 earthquakes
S20260402.2(26.4km)
2 Apr
5 days 5 hours
150 earthquakes
S20260402.5(20.0km)
2 Apr
8 days 13 hours
107 earthquakes
S20260404.1(23.3km)
3 Apr
1 day 10 hours
43 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20260402.1 in the Molucca Sea: Geological Context and Event Analysis

The Molucca Sea, situated between the islands of Sulawesi and Halmahera in eastern Indonesia, lies within one of the world's most tectonically complex regions. This area features intricate interactions among the Sunda Plate, Philippine Sea Plate, and smaller fragments such as the Molucca Sea Plate, resulting in multiple subduction zones and frequent seismic activity. The convergence drives high seismicity, with earthquakes commonly occurring at depths ranging from shallow crustal levels to intermediate depths exceeding 100 km.

Seismic swarm S20260402.1 began at 23:15 on 1 April 2026 and concluded at 18:05 on 14 April 2026. Over 306 hours and 49 minutes, 397 earthquakes were recorded in the Molucca Sea. Analysis of the first 100 events reveals magnitudes primarily between 2.5 and 5.9, with depths mostly between 3 km and 69 km. Notable events include a magnitude 5.9 earthquake at 35 km depth on 2 April at 14:13:49 UTC and a magnitude 5.8 event at similar depth shortly after. Earlier activity featured several magnitude 4.0–4.6 quakes clustered between 10 km and 40 km depth, indicating a mix of shallow and intermediate-focus seismicity.

Such swarms align with the region's historical pattern. Since 2000, 11 swarms have occurred in the Molucca Sea, with documented episodes in 2001 (3 swarms), 2007 (2), 2014 (3), 2019 (2), and 2026 (1). These clusters often reflect stress adjustments along subduction interfaces rather than isolated mainshock-aftershock sequences.

The Molucca Sea's geology stems from ongoing plate collision and rollback processes that have shaped the double-arc system of Halmahera and Sangihe. This configuration produces frequent moderate earthquakes, with depths commonly under 50 km in swarm events, consistent with the observed data. Updated tectonic models emphasize the role of slab interactions in generating diffuse seismicity across the region.

References
SeismoSight internal classification for swarm parameters and event catalog.
USGS Earthquake Hazards Program for regional tectonic framework.
Global CMT catalog for historical subduction zone characteristics.