Today, in the wake of the intensifying seismic swarm on La Palma that began on the 11^th September, the Government of the Canary Islands have activated the Scientific Committee of the Special Plan for Civil Protection and Attention to Emergencies due to Volcanic Risk (PEVOLCA). Alongside this activation, the volcanic traffic light alert system has been raised from green to yellow in the municipalities of Fuencaliente, Los Llanos de Aridane, El Paso and Mazo. The yellow traffic light allows for an intensification of communication to the population, volcano and seismic monitoring, as well as increased surveillance.

Since the swarm started, there have been more than 400 earthquakes, some of which have been felt by the population. The swarm represents the 9^th seismic swarm in southern La Palma since anomalous seismic activity began in the area in October 2017. This current swarm is the most intense of any of these swarms, and is also significant in that the majority of the earthquakes are shallower at around 12 km depth, relative to previous swarms that have taken place at 20-30 km depth. Furthermore, Helium-3 emission data, the ratios of which can be used to infer the source of the swarm, register the highest values seen in 30 years, and confirm a magmatic source for the current activity.

Sources: Government of the Canary Islands, PEVOLCA, Involcan, IGN, DSN, Cabildo La Palma, 112 Canarias

A map of the location and magnitude of the earthquakes since the start of the seismic swarm on the 11th. Image credit: IGN