The Canary holiday island of La Palma has experienced more than 300 mini-earthquakes over the past week, scientists report.
A majority of the tremors were so small they could not be located by scientists, let alone felt by any residents on La Palma.
The latest mini-quakes follow the 40 tremors that were recorded two weekends ago, taking the total to 352 in just ten days.
Scientists are now monitoring the seismic activity on La Palma 24 hours per day, and are set to carry out tests on the slopes of the island’s active volcano – Cumbre Vieja.
Between October 6 and 7, more than 40 tremors were recorded, with the most powerful hitting 2.7 on the Richter scale, located at a depth of 17.4miles.
A few days of peace followed between October 10 and 13, when seismographers on La Palma picked up another ‘swarm’ of tremors.
On October 13, some 44 quakes were recorded at depths of between 9.3miles and 13.6miles, the most powerful at 2.1 on the Richter scale.
The National Geographic Institute (IGN) notes that volcanic monitoring will continue for 24 hours per day, and that a team is to be sent to La Palma to carry out CO2 profiles and structural studies of Cumbre Vieja.
These were put in place following the first round of mini-quakes reported last week, increasing the ability to record seismic activity.
La Palma is the most north-westerly island of the Canary Islands, and is home to some 86,000 people – a population which increases significantly during tourist season.
Like the other Canary Islands, La Palma is volcanic and is considered the most ‘active’ in the archipelago.
The most recent eruption on the island, which saw the Cumbre Vieja – ‘Old Summit’ – volcano erupt, took place in 1971.
The current event has been dubbed a ‘seismic swarm’, and while unusual, large numbers of these smaller tremors are not abnormal, the director of the IGN in the Canary Islands, María José Blanco, told Canarias7.
However, she added that they had “never recorded a similar swarm’ since monitoring began on La Palma.
The IGN and the Volcanological Institute of the Canary Islands (Involcan) have increased surveillance on the island to monitor the increase in seismic activity.
A spokesperson for Involcan told Canarias7 that ‘seismic swarms’ are ‘absolutely normal’ for an active volcano such as Cumbre Vieja.