Location:

Period:

2 Dec 2023 17:14:46 - 5 Dec 2023 20:23:28 (3 days 3 hours 8 minutes)

Volcanoes in 100km radius:

None

Earthquakes:

9 swarms found nearby.

2009

PS20090521.1(79.8km)

21 May

8 hours

5 earthquakes

2014

PS20140530.1(112.8km)

30 May

5 hours

6 earthquakes

PS20140531.1(111.4km)

31 May

1 hours

9 earthquakes

2018

PS20181029.1(16.3km)

29 Oct

7 hours

5 earthquakes

2023

PS20231202.1(76.2km)

2 Dec

5 days 19 hours

107 earthquakes

S20231203.2(29.8km)

2 Dec

5 days 21 hours

67 earthquakes

PS20231212.1(46.8km)

11 Dec

14 hours

5 earthquakes

PS20231224.1(62.5km)

23 Dec

15 hours

5 earthquakes

2024

PS20240803.1(45.0km)

2 Aug

5 hours

7 earthquakes

AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20231203.3 East of Tidman, Philippines

A notable seismic swarm, designated S20231203.3, was recorded 15 km east of Tidman in the Philippines. The sequence began at 17:14 on 2 December 2023 and concluded at 20:23 on 5 December 2023, spanning 75 hours and 8 minutes. During this interval, 41 earthquakes were registered, with magnitudes ranging from 3.0 to 4.9 and focal depths predominantly between 50 km and 92 km, though several events occurred at shallower depths down to 9 km.

The swarm exhibited a clustered pattern of moderate events without a single dominant mainshock. Initial activity on 2 December included multiple events above magnitude 4.0, such as a 4.7 quake at 77 km depth. Activity intensified overnight into 3 December, peaking with a magnitude 4.9 event at 50 km depth. Subsequent days showed continued moderate shaking, including a magnitude 4.8 event on 5 December at 76 km depth. Shallower events, such as those at 9 km and 11 km on 4 and 5 December, were interspersed among deeper occurrences, highlighting varied rupture depths within the sequence.

This swarm aligns with the tectonic setting of eastern Mindanao, where the Philippine archipelago experiences ongoing deformation from the interaction of the Philippine Sea Plate and the Eurasian Plate. The region lies near major fault systems and subduction-related structures that accommodate plate convergence, resulting in frequent seismic episodes. Earthquake swarms in such environments often reflect fluid migration or stress redistribution along fault networks rather than a classic foreshock-mainshock-aftershock progression.

Historical records indicate that six comparable swarms have occurred in the area since 1 January 2000. These took place in 2009 (one swarm), 2014 (two swarms), 2018 (one swarm), and 2023 (two swarms). The recurrence underscores the persistent seismic character of the locality, where clusters of events periodically relieve accumulated strain.

Overall, Swarm S20231203.3 represents a typical expression of background tectonic activity in this part of the Philippines. Continued monitoring remains essential given the region's established seismicity patterns.

References:
SeismoSight internal swarm classification data
USGS Earthquake Catalog (general regional tectonics)
Philippine Institute of Volcanology and Seismology (PHIVOLCS) regional seismic summaries