Location:

Period:

31 May 2026 21:34:18 - 4 Jun 2026 11:58:49 (3 days 14 hours 24 minutes)

Volcanoes in 100km radius:

None

Earthquakes:

6 swarms found nearby.

2008

PS20081219.1(34.4km)

18 Dec

1 day 14 hours

8 earthquakes

2010

PS20100304.1(114.9km)

3 Mar

1 day 13 hours

7 earthquakes

PS20100308.2(18.1km)

8 Mar

6 hours

6 earthquakes

2011

PS20110317.2(24.9km)

16 Mar

16 hours

5 earthquakes

2015

PS20150917.2(75.3km)

17 Sep

21 hours

9 earthquakes

2017

PS20170428.1(53.7km)

28 Apr

2 hours

6 earthquakes

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Seismic Swarm S20260601.1: Offshore Valparaíso, Chile

SeismoSight registered seismic swarm S20260601.1 beginning at 21:34 on 31 May 2026 and concluding at 11:58 on 4 June 2026. The sequence, located offshore Valparaíso, Chile, produced 51 earthquakes over 86 hours and 24 minutes.

The swarm initiated with a magnitude 6.0 event at 25 km depth. Subsequent activity included a magnitude 4.9 quake at 10 km depth shortly afterward, followed by numerous events between magnitudes 2.5 and 4.0. Depths throughout the swarm ranged from 10 km to 31 km, with the majority clustered between 24 km and 30 km. Later notable shocks reached magnitude 3.9 on 1 June and magnitude 3.8 on both 3 June and 4 June.

This pattern reflects typical swarm behavior in subduction zones, where clustered seismicity occurs without a single dominant mainshock-aftershock sequence. The distribution of magnitudes and depths suggests distributed stress adjustment along the plate interface rather than rupture of a single large fault segment.

Offshore Valparaíso lies within the Peru-Chile Trench, where the Nazca Plate subducts beneath the South American Plate at a rate of approximately 6.6 cm per year. This tectonic setting generates frequent seismicity across a wide range of magnitudes. The region has produced great earthquakes historically, including the 2010 Maule event of magnitude 8.8 located to the south.

Swarm activity in the area is documented since 2000, with six prior episodes recorded in 2008, 2010, 2011, 2015, and 2017. These events indicate recurring episodic slip or fluid-related processes at intermediate depths along the megathrust. Depths observed in S20260601.1 align with the seismogenic zone where interplate coupling varies.

No damage or tsunami was associated with the 2026 swarm. Continued monitoring remains essential given the region's high seismic hazard and history of both moderate swarms and infrequent great earthquakes.

References
SeismoSight internal classification records for swarm S20260601.1.
USGS Earthquake Catalog (historical regional seismicity).
Global CMT Project (subduction zone parameters).