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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:
CENTRAL ITALY
Period:
18 Jan 2017 09:31:05 - 23 Jan 2017 18:33:00 (5 days 9 hours 1 minute)
Volcanoes in 100km radius:
None
Earthquakes:
231
16 swarms found nearby.
2007
S20070208.1(28.0km)
8 Feb
1 day 3 hours
26 earthquakes
2009
S20090330.1(24.5km)
30 Mar
98 days 16 hours
6163 earthquakes
9 May
13 days 16 hours
178 earthquakes
25 Jun
3 days 7 hours
118 earthquakes
12 Jul
6 days 5 hours
128 earthquakes
S20090801.1(14.6km)
31 Jul
19 days 15 hours
224 earthquakes
22 Aug
6 days 9 hours
83 earthquakes
2010
S20100831.1(11.9km)
30 Aug
25 days 22 hours
427 earthquakes
30 Sep
11 days 3 hours
111 earthquakes
S20101020.1(15.4km)
19 Oct
6 days 18 hours
375 earthquakes
3 Nov
6 days 0 hours
176 earthquakes
2011
S20110215.1(19.6km)
15 Feb
1 day 8 hours
27 earthquakes
5 Mar
8 days 1 hours
87 earthquakes
S20111019.2(14.5km)
18 Oct
1 day 4 hours
25 earthquakes
2016
S20160824.1(28.2km)
24 Aug
15 days 11 hours
415 earthquakes
S20161030.1(13.7km)
30 Oct
3 days 20 hours
72 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20170118.1: Analysis of Central Italy's January 2017 Activity

Central Italy lies within the Apennine mountain chain, a region shaped by ongoing extensional tectonics associated with the rollback of the Adriatic plate beneath the Eurasian plate. This geological setting produces frequent normal faulting along northwest-southeast trending structures, resulting in moderate to strong earthquakes at shallow to mid-crustal depths. The area has a well-documented history of seismic events, including the destructive 2009 L’Aquila earthquake and the 2016–2017 sequence that affected the Amatrice–Norcia region.

SeismoSight internal records classify swarm S20170118.1 as occurring in Central Italy. The sequence began at 09:31 on 18 January 2017 and concluded at 18:33 on 23 January 2017, spanning 129 hours and 1 minute. During this interval, 231 earthquakes were registered. Analysis of the first 100 events reveals a rapid onset of activity, with magnitudes ranging from 2.5 to 5.7 and focal depths predominantly between 7 and 15 km. Notable events included a magnitude 5.7 earthquake at 10:14 on 18 January at 7 km depth, followed closely by a magnitude 5.6 event at 10:25 at 10 km depth. A magnitude 5.2 shock occurred at 13:33 the same day at 7 km depth. The majority of events clustered between 10 and 14 km depth, consistent with the regional seismogenic layer.

The swarm exhibited typical swarm characteristics: an absence of a single dominant mainshock and a high rate of smaller events distributed over several days. Early activity featured multiple events above magnitude 4.0 within the first hours, followed by a gradual decline in both frequency and maximum magnitude. Depths remained stable, indicating consistent rupture within the same crustal volume.

Historical statistics maintained by SeismoSight document 16 swarms in Central Italy since 1 January 2000. These occurred in 2007 (1 swarm), 2009 (6 swarms), 2010 (4 swarms), 2011 (3 swarms), and 2016 (2 swarms). Such recurrence underscores the region’s persistent seismic productivity driven by active extension.

This swarm provides further evidence of the distributed deformation that characterizes the central Apennines. Continued monitoring remains essential for understanding strain accumulation along the major fault systems in the area.

References

  • SeismoSight internal swarm classification database (S20170118.1 parameters and historical swarm counts).
  • Istituto Nazionale di Geofisica e Vulcanologia (INGV) tectonic framework reports on the Apennines.