Location:

Period:

11 Feb 2011 20:05:30 - 12 Feb 2011 01:17:01 (5 hours 11 minutes)

Volcanoes in 100km radius:

None

Earthquakes:

M 7.0+:

M 8.8; 2010 Maule, Chile Earthquake; (27 Feb 2010) (92km from the swarm center)

9 swarms found nearby.

2010

PS20100227.2(21.6km)

27 Feb

2 days 9 hours

41 earthquakes

PS20100227.3(164.1km)

27 Feb

1 day 20 hours

28 earthquakes

PS20100227.6(90.2km)

27 Feb

13 hours

10 earthquakes

PS20100302.1(54.3km)

2 Mar

1 day 13 hours

7 earthquakes

PS20100305.2(58.3km)

5 Mar

1 day 5 hours

7 earthquakes

PS20100310.1(31.6km)

10 Mar

6 hours

5 earthquakes

PS20100313.1(46.3km)

13 Mar

17 hours

6 earthquakes

PS20100316.1(66.2km)

15 Mar

16 hours

5 earthquakes

2015

PS20150319.1(111.2km)

18 Mar

14 hours

5 earthquakes

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Seismic Swarm PS20110211.1: Geological Context Near Talcahuano, Chile

Seismic swarm PS20110211.1 occurred approximately 51 km northwest of Talcahuano, Chile, within the tectonically active zone of the Peru-Chile Trench. The event sequence began at 20:05 on 11 February 2011 and concluded at 01:17 on 12 February 2011, spanning 5 hours and 11 minutes. During this period, seven earthquakes were recorded, with magnitudes ranging from 4.8 to 6.9 and focal depths between 15 km and 38 km.

The swarm initiated with a magnitude 6.9 event at 26 km depth, followed by a magnitude 5.3 shock at 38 km. Subsequent activity included events of magnitude 4.8 at 18 km, two magnitude 5.3 shocks at 17 km and 24 km, a magnitude 5.9 at 15 km, and a concluding magnitude 6.1 at 16 km depth. These clustered occurrences reflect typical swarm behavior in subduction settings, where stress redistribution along the plate interface can trigger multiple moderate events without a single dominant mainshock-aftershock pattern.

Chile's coastal region, including the area near Talcahuano, lies above the convergent boundary where the Nazca Plate subducts beneath the South American Plate at rates of approximately 6-7 cm per year. This tectonic configuration places the region within the Pacific Ring of Fire, producing frequent seismicity and volcanic activity. The subduction zone has generated some of the world's largest recorded earthquakes, with historical precedents including the 1960 Valdivia event and more recent activity.

The 2010 Maule earthquake, magnitude 8.8, struck on 27 February 2010 at a location 92 km from the swarm center. This megathrust rupture released significant strain along the plate boundary and likely influenced subsequent seismic patterns in the region. Since 1 January 2000, eight swarms have been documented in the area, with the first occurring in 2010, indicating episodic clustering of events amid the broader aftershock sequence from major subduction earthquakes.

Such swarms provide insight into fault mechanics and stress transfer in the overriding plate and along the megathrust. Depths predominantly in the 15-38 km range align with the seismogenic zone of the subduction interface, where brittle failure occurs. Monitoring these sequences aids in refining seismic hazard assessments for central Chile, where population centers like Talcahuano remain exposed to potential strong ground motion.

References

SeismoSight internal swarm classification data
USGS Earthquake Catalog for Maule 2010 event parameters