DashboardNewsSwarmsM 7.0+
VolcanoesSupervolcanoesRegionsGlobal
Favorites
BlogAbout
Privacy PolicyDisclaimer
Follow
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:
STRAIT OF GIBRALTAR
Period:
3 Oct 2022 19:45:42 - 9 Oct 2022 00:19:06 (5 days 4 hours 33 minutes)
Volcanoes in 100km radius:
None
Earthquakes:
91
16 swarms found nearby.
2016
PS20160125.1(17.2km)
25 Jan
1 hours
6 earthquakes
2021
15 May
3 days 23 hours
51 earthquakes
6 Jun
11 days 1 hours
144 earthquakes
S20210730.3(26.4km)
29 Jul
57 days 9 hours
1361 earthquakes
S20211114.1(16.5km)
13 Nov
5 days 5 hours
78 earthquakes
20 Nov
5 days 9 hours
57 earthquakes
5 Dec
5 days 18 hours
57 earthquakes
20 Dec
10 days 0 hours
135 earthquakes
2022
5 Feb
8 days 15 hours
147 earthquakes
7 Apr
28 days 16 hours
392 earthquakes
19 May
21 days 19 hours
412 earthquakes
16 Jun
6 days 9 hours
74 earthquakes
19 Jul
22 days 3 hours
330 earthquakes
15 Sep
4 days 1 hours
55 earthquakes
15 Oct
5 days 23 hours
62 earthquakes
2024
S20240316.1(10.3km)
15 Mar
2 days 2 hours
32 earthquakes
AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm in the Strait of Gibraltar: October 2022

The Strait of Gibraltar marks the narrow marine passage separating the Iberian Peninsula from northwest Africa, connecting the Atlantic Ocean with the Mediterranean Sea. This tectonically dynamic zone lies at the convergent boundary between the African and Eurasian plates, where north-northwestward motion of the African plate produces ongoing compression, strike-slip faulting, and moderate seismic activity. The region’s geology features a complex assemblage of sedimentary basins, thrust faults, and transform structures that accommodate plate-boundary deformation. Historical records document recurrent earthquake sequences linked to these processes, with the Strait experiencing both isolated events and episodic swarms.

SeismoSight internal classification identifies Swarm S20221004.1 as a notable sequence in this setting. The swarm initiated at 19:45 on 3 October 2022 and concluded at 00:19 on 9 October 2022, spanning 124 hours and 33 minutes. During this interval, 91 earthquakes were recorded. Magnitudes ranged from 1.5 to 4.9, with the majority of events clustered between 2.0 and 2.7. Focal depths varied from near-surface values to approximately 30 km, indicating activity within the upper crust.

The sequence began with several low-magnitude events on 3 October. Activity intensified on 4 October, culminating in the largest event—a magnitude 4.9 earthquake at 15:39—followed by an immediate aftershock of magnitude 2.3. Subsequent hours produced a dense cluster of events, many between 1.7 and 2.7, distributed across depths of 5–30 km. Elevated rates persisted through 5 October, including a magnitude 3.3 event at 12:45, before gradually declining. Isolated events continued until the swarm’s termination on 9 October.

Statistical context places this swarm within a longer record of seismic clustering in the Strait. Since 1 January 2000, fourteen swarms have been documented. Earlier episodes occurred in 2016 (one swarm), 2021 (seven swarms), and 2022 (six swarms, including the present sequence). These repeated swarms underscore the Strait’s propensity for swarm-type seismicity rather than isolated mainshock-aftershock sequences.

The October 2022 swarm exhibited typical characteristics of plate-boundary swarms: a rapid onset, high event rate over several days, absence of a single dominant mainshock, and migration of activity across a range of depths. Such patterns are consistent with fluid migration or aseismic slip triggering brittle failure along pre-existing faults within the transpressive regime of the Gibraltar Arc.

  • SeismoSight internal swarm catalog (S20221004.1)
  • Regional tectonic summaries from the European-Mediterranean Seismological Centre
  • Geological framework publications on the Gibraltar Arc and Betic-Rif orogen