canary islands

El Hierro reflects on 12 years since the Tagoro underwater eruption

The depth at which the phenomenon occurred on El Hierro prevented the magmatic material from reaching the surface, but a greenish stain was visible, even when observed from satellites.

12 years have passed since the underwater eruption of the Tagoro volcano, located south of La Restinga on El Hierro island. The eruption began on October 10, 2011, when seismic stations detected a volcanic tremor signal around 05:00 hours.

The National Geographic Institute (IGN) noted that the process leading to the eruption had started in July 2011 and lasted for 80 days, during which there were over 10,000 earthquakes, causing ground deformations of several centimeters. This period culminated in the eruption that occurred exactly 12 years ago today.

According to the IGN, during the initial two months of the eruption, there was intense seismic activity concentrated in the northern part of the island, approximately 20 kilometers from the eruption site. This seismic activity appeared to mark the origin of the magma, with the largest felt earthquake measuring magnitude 4.6.

El Hierro reflects on 12 years since the Tagoro underwater eruption

The underwater eruption took place about five kilometers off the south coast of El Hierro at a depth of approximately one kilometer. The depth of the eruption prevented the magmatic material from reaching the surface, but it left a greenish stain visible in the sea, even detectable from satellites. This stain gradually spread over the following days and became visible worldwide.

During the eruption, xenopumites or globes, colloquially known as “restingolites,” emerged. These were formed when rising basaltic magma encountered lighter material, which was covered by the basalt. The lighter material floated in the sea due to its low density. The origin of these restingolites remains a subject of debate.

These floating rocks were at a high temperature, around 400 degrees Celsius, and hollow, allowing them to float for a brief period. Eventually, seawater entered the hollow rocks, causing them to sink, similar to ships.


The eruption led to the emission of gases, resulting in the destruction of fauna and flora in the area, causing fish to float to the surface during the initial days of the phenomenon. However, 12 years later, life has once again flourished around the site of the underwater volcano.

This eruption marked a significant milestone in Spain’s history, as it was the first eruption to be monitored from its precursors. The IGN had been responsible for volcanic monitoring since 2004, utilizing techniques such as seismology, geodesy, and geochemistry.

The eruption of the Tagoro volcano concluded on March 5, 2012, with the disappearance of tremors since February 15. The estimated total volume of material expelled during the eruption ranged between 300 and 400 million cubic meters.

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