Seismic Swarm S20130319.1 in the Canary Islands Region

The Canary Islands form a volcanic archipelago located approximately 100 kilometers off the northwest coast of Africa, belonging to Spain. These islands originated from hotspot volcanism linked to a mantle plume beneath the African plate, resulting in basaltic shield volcanoes and ongoing geological dynamism. Seismic activity in the region frequently relates to magma movement and fluid migration within the crust, with historical records documenting eruptions on islands such as Tenerife, La Palma, and El Hierro.

Seismic swarm S20130319.1 was recorded in the Canary Islands region between 14:29 on 18 March 2013 and 13:31 on 19 March 2013. Over this 23-hour period, 29 earthquakes occurred. Magnitudes ranged from 2.4 to 3.1, and focal depths varied between 10 and 21 kilometers, with most events clustered around 16 to 19 kilometers. The sequence featured repeated events of magnitude 2.5 to 2.8, interspersed with stronger shocks reaching 3.0 and 3.1. Depths remained relatively stable in the mid-crustal range, consistent with volcanic or hydrothermal processes rather than tectonic faulting.

The swarm exhibited typical characteristics of volcanic seismicity, beginning with events at 14:29 and 14:40 (both magnitude 2.6), followed by a cluster in the late afternoon including the largest event of magnitude 3.1 at 17:39. Subsequent activity continued at lower magnitudes through the evening and into the following day, concluding with a final magnitude 2.5 event at 13:31. No single dominant mainshock was evident, confirming the swarm classification.

This event fits within the established seismic history of the archipelago. Since 2000, eight prior swarms have been documented, including five in 2011 and three in 2012. These episodes often correlate with periods of volcanic unrest, reflecting episodic magma intrusion or pressure changes in the subsurface plumbing systems of the islands.

Such swarms provide valuable indicators for monitoring volcanic hazards in this geologically active province. Continued observation supports improved understanding of the Canary Islands' dynamic subsurface environment.

References: Instituto Geográfico Nacional (IGN) seismic catalogs Geological mapping from the Spanish Instituto Geológico y Minero de España (IGME) Global Volcanism Program records on Canary Islands volcanism