Note:This page contains AI-generated content for informational and entertainment purposes only. It may contain inaccuracies. Raw event data is from USGS and EMSC. All statistics, lists, and derived information are generated by this site. Full disclaimerFound an error?
Location:
63 km W of Illapel, Chile
Period:
29 Mar 2007 14:40:44 - 29 Mar 2007 18:31:58 (3 hours 51 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
6
M 7.0+:
M 7.0; 25 km WNW of Illapel, Chile; (16 Sep 2015) (45km from the swarm center)
M 8.3; 48 km W of Illapel, Chile; (16 Sep 2015) (22km from the swarm center)
14 swarms found nearby.
2003
S20030620.1(101.0km)
19 Jun
10 days 9 hours
233 earthquakes
S20030724.1(95.1km)
23 Jul
2 days 22 hours
48 earthquakes
2006
S20061013.1(26.0km)
12 Oct
3 days 13 hours
50 earthquakes
2008
PS20081219.1(106.1km)
18 Dec
1 day 14 hours
8 earthquakes
2010
PS20100308.2(117.6km)
8 Mar
6 hours
6 earthquakes
2011
PS20110317.2(110.0km)
16 Mar
16 hours
5 earthquakes
2015
PS20150916.2(30.3km)
16 Sep
1 day 14 hours
48 earthquakes
PS20150917.1(92.1km)
16 Sep
4 hours
8 earthquakes
S20150917.1(34.2km)
16 Sep
3 days 1 hours
40 earthquakes
PS20150917.2(81.0km)
17 Sep
21 hours
9 earthquakes
PS20150919.1(113.2km)
19 Sep
1 day 12 hours
10 earthquakes
PS20150921.1(43.7km)
21 Sep
1 day 1 hours
7 earthquakes
2017
PS20170428.1(183.8km)
28 Apr
2 hours
6 earthquakes
2022
S20220504.1(71.2km)
4 May
1 day 5 hours
42 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm PS20070329.1: Analysis of Events Near Illapel, Chile

The seismic swarm designated PS20070329.1 occurred 63 km west of Illapel, Chile, on 29 March 2007. It began at 14:40 and concluded at 18:31, encompassing six earthquakes over 3 hours and 51 minutes. This sequence unfolded in a tectonically active segment of the subduction zone where the Nazca Plate descends beneath the South American Plate along the Peru-Chile Trench.

The recorded events exhibited the following parameters:

  • 14:40:44, magnitude 5.6 at 25 km depth
  • 17:09:01, magnitude 5.5 at 2 km depth
  • 17:09:07, magnitude 5.8 at 33 km depth
  • 17:28:04, magnitude 4.1 at 31 km depth
  • 17:46:20, magnitude 5.3 at 4 km depth
  • 18:31:58, magnitude 5.0 at 29 km depth

These shallow to intermediate-depth events reflect typical stress adjustments within the overriding plate and the subducting slab interface. Central Chile experiences frequent seismic swarms due to the ongoing convergence rate of 6–7 cm per year, which generates both interplate and intraplate seismicity.

Historical records since 2000 indicate only three prior swarms in the broader Illapel area: two in 2003 and one in 2006. The 2007 swarm fits within this sparse pattern of clustered activity. The region later hosted two significant earthquakes on 16 September 2015: a magnitude 7.0 event 25 km west-northwest of Illapel and a magnitude 8.3 mainshock 48 km west of the city. The 2015 epicenters lay 45 km and 22 km, respectively, from the 2007 swarm centroid, underscoring the persistent seismic hazard along this segment of the margin.

Seismic swarms in subduction settings often serve as indicators of localized stress redistribution rather than immediate precursors to great earthquakes. The 2007 sequence released moderate energy without triggering a larger rupture at the time, consistent with the variable coupling observed along the Chilean margin. Ongoing monitoring by national and international networks continues to track microseismicity in this zone to refine hazard assessments.

References

  • SeismoSight internal swarm classification records
  • USGS Earthquake Catalog (events since 2000)
  • Tectonic framework of the Peru-Chile Trench, Geological Society of America publications