Location:

Period:

30 May 2014 15:26:14 - 30 May 2014 20:37:55 (5 hours 11 minutes)

Volcanoes in 100km radius:

None

Earthquakes:

M 7.0+:

M 7.6; 19 km E of Gamut, Philippines; (2 Dec 2023) (91km from the swarm center)

14 swarms found nearby.

2009

PS20090521.1(171.2km)

21 May

8 hours

5 earthquakes

2012

PS20120831.1(121.2km)

31 Aug

19 hours

15 earthquakes

PS20120904.1(138.3km)

4 Sep

14 hours

9 earthquakes

2014

PS20140531.1(2.5km)

31 May

1 hours

9 earthquakes

2018

PS20181029.1(96.7km)

29 Oct

7 hours

5 earthquakes

2019

PS20190208.1(56.6km)

8 Feb

9 hours

7 earthquakes

PS20190426.1(47.5km)

26 Apr

15 hours

9 earthquakes

2023

PS20231202.1(67.6km)

2 Dec

5 days 19 hours

107 earthquakes

S20231202.2(114.9km)

2 Dec

4 days 13 hours

158 earthquakes

S20231203.2(98.6km)

2 Dec

5 days 21 hours

67 earthquakes

S20231203.3(112.8km)

2 Dec

3 days 3 hours

41 earthquakes

PS20231212.1(92.4km)

11 Dec

14 hours

5 earthquakes

PS20231224.1(120.3km)

23 Dec

15 hours

5 earthquakes

2024

PS20240803.1(140.0km)

2 Aug

5 hours

7 earthquakes

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

Seismic Swarm PS20140530.1: Analysis of Activity Near Cortes, Philippines

The seismic swarm designated PS20140530.1 occurred on 30 May 2014 in the central Philippines, centered approximately 70 km east-northeast of Cortes in Bohol province. The sequence began at 15:26 UTC and concluded at 20:37 UTC, encompassing a total duration of five hours and eleven minutes. During this interval, six earthquakes were recorded, with magnitudes ranging from 4.5 to 5.7 and focal depths between 8 km and 18 km.

The events unfolded as follows: the initial shock at 15:26:14 registered magnitude 5.7 at 14 km depth, followed by a magnitude 5.1 event at 16:36:21 (10 km depth). Subsequent activity included a magnitude 4.5 at 17:06:09 (8 km), magnitude 5.3 at 17:41:25 (12 km), magnitude 5.0 at 17:53:07 (18 km), and a final magnitude 5.0 at 20:37:55 (10 km). All events clustered tightly in both time and space, characteristic of swarm behavior without a dominant mainshock-aftershock pattern.

The Philippines occupies a tectonically active segment of the Pacific Ring of Fire, where convergence between the Philippine Sea Plate and the Eurasian Plate drives subduction along the Philippine Trench and associated fault systems. Bohol island lies near the western edge of the Philippine Fault Zone and the Cotabato Fault system, regions historically prone to moderate seismic swarms due to crustal stresses from oblique subduction and strike-slip motion. Depths in the 8–18 km range align with typical shallow crustal seismicity in this setting.

Historical records since 1 January 2000 indicate only three prior swarms in the immediate region: one in 2009 and two in 2012. This low frequency underscores the episodic nature of swarm activity amid ongoing plate-boundary deformation. A notable regional event was the magnitude 7.6 earthquake on 2 December 2023, located 19 km east of Gamut and 91 km from the 2014 swarm center, highlighting the potential for larger ruptures along nearby structures.

Such swarms provide valuable data for understanding stress transfer and fault interactions in subduction-influenced crust. Continued monitoring by networks such as PHIVOLCS supports improved hazard assessment in this high-seismicity archipelago.

References

SeismoSight internal swarm classification PS20140530.1
USGS earthquake catalog (regional tectonics and historical events)