Location:

Period:

28 Oct 2011 15:19:31 - 6 Nov 2011 05:07:28 (8 days 13 hours 47 minutes)

Volcanoes in 100km radius:

Tenduruk Dagi(79km)

Earthquakes:

155

M 7.0+:

M 7.1; 27 km NNE of Van, Turkey; (23 Oct 2011) (2km from the swarm center)

12 swarms found nearby.

2011

PS20111023.1(30.1km)

23 Oct

1 day 4 hours

10 earthquakes

S20111023.1(24.9km)

23 Oct

69 days 9 hours

2474 earthquakes

S20111023.2(5.2km)

23 Oct

14 days 17 hours

739 earthquakes

S20111024.1(27.5km)

23 Oct

4 days 0 hours

78 earthquakes

S20111027.2(27.6km)

26 Oct

2 days 14 hours

99 earthquakes

S20111030.1(15.5km)

29 Oct

2 days 2 hours

46 earthquakes

S20111105.1(23.8km)

4 Nov

24 days 12 hours

631 earthquakes

S20111107.2(29.0km)

6 Nov

3 days 18 hours

79 earthquakes

S20111109.1(25.5km)

9 Nov

11 days 2 hours

333 earthquakes

S20111115.1(9.0km)

14 Nov

5 days 0 hours

63 earthquakes

S20111129.1(15.1km)

28 Nov

35 days 13 hours

454 earthquakes

2022

S20220613.1(21.8km)

12 Jun

3 days 2 hours

44 earthquakes

AI-generated article — for informational and entertainment purposes only. May contain inaccuracies. Full disclaimerFound an error?

Seismic Swarm S20111029.1 in Eastern Turkey

Seismic swarm S20111029.1 was recorded in eastern Turkey, beginning at 15:19 on 28 October 2011 and concluding at 05:07 on 6 November 2011. Over 205 hours and 47 minutes, a total of 155 earthquakes were registered. The activity occurred near the center of a magnitude 7.1 event that struck 27 km NNE of Van five days earlier, placing the swarm roughly 2 km from that epicenter.

Analysis of the first 100 events reveals predominantly shallow seismicity. Depths ranged from 2 km to 35 km, with the majority occurring between 2 km and 20 km. Magnitudes varied from 2.1 to 4.0. The largest event in this subset reached magnitude 4.0 at 09:08 on 29 October at a depth of 2 km. Other notable shocks included a magnitude 3.7 at 20:29 on 31 October (depth 2 km) and several magnitude 3.2 events clustered between 31 October and 2 November. Time intervals between events were often short, with multiple shocks occurring within minutes on several days, particularly 29–31 October.

This swarm represents the first documented since 2000 in the region, where five such sequences have now been identified. The preceding magnitude 7.1 Van earthquake on 23 October 2011 occurred within the same tectonic setting and likely influenced subsequent activity through stress redistribution.

Eastern Turkey lies within the Alpine-Himalayan orogenic belt, where ongoing convergence between the Arabian and Eurasian plates drives active deformation across the Eastern Anatolian Plateau. The area features a complex network of strike-slip and thrust faults, including segments of the East Anatolian Fault Zone. Lake Van occupies a tectonic depression shaped by this plate interaction, contributing to elevated seismic hazard. Historical records document repeated strong earthquakes, with the 2011 Van event producing widespread damage and highlighting the region's persistent vulnerability.

Updated geological assessments confirm continued plate-boundary strain accumulation, consistent with the observed swarm characteristics and the preceding mainshock. Shallow focal depths align with known brittle failure in the upper crust of this collision zone.

References

SeismoSight internal swarm classification data
USGS Earthquake Catalog (Van 2011 event parameters)
Geological Survey of Turkey regional tectonic reports