“On the same Wednesday, an hour before sunset, the earth smoked and with a great roar the first mouth was opened on flat land […]; and then, immediately, in an hour’s time, another 17 mouths were opened up to the foot of said mountain, from where a thick fluid matter fired and with the smell of sulfur came out, which joined together formed a river of fire that address Sea”. With these words, the Canarian priest, historian, biologist and writer José Viera y Clavijo (1731-1813) collected the eruption of the Fuencaliente volcano, south of La Palma, between 1677 and 1678. The Canarian historian cited a single witness, Juan Pinto de Guisla, to account for that eruption, now turned into a tourist attraction. Just 375 years later, another volcano on the island, still unnamed, has surpassed it both in duration and in number of witnesses and scientists. Next on the list is the Martín or Tigalate volcano, which erupted in 1646 and lasted 82 days. In between is the Tao volcano on the other quintessential volcanic island, Lanzarote.
One of the most accepted theories about the creation of the Canary Islands holds that the archipelago is located on the African continental plate, which fleet over the earth’s mantle in an easterly direction at a rate similar to that of fingernails. About 20 million years ago, the plate began to pass over the hotspot, which injected magma and began to create the first islands: Fuerteventura and Lanzarote. La Palma and El Hierro are the youngest islands, barely 1.8 and 1.2 million years old, respectively. The hot spot is still under them and that is why they have active volcanoes that make them grow in extension and surface.
Historical records cover approximately the last six centuries, a period in which more than twenty eruptions have been recorded in the Canary Islands. The Cumbre Vieja de La Palma, where the earth exploded on September 19, constitutes one of the most active volcanic complexes in the Canary Islands. Not surprisingly, there have been two of the last three eruptions recorded on the islands, that of the San Juan volcano (1949) and the Teneguía (1971).
The development of the island (about 82,000 registered inhabitants) and the situation of the volcano (on the western slope of a mountain range that divides the island in half) have caused more damage than all its predecessors. And, worst of all, scientists do not see the end of the process. So far, the lava has covered 1,065 hectares of land, according to the latest data from the European geospatial measurement system Copernicus. On its way, it has razed almost 1,500 buildings, of which about 1,100 homes, according to data from the Cadastre. The number of evacuees continues to be around 7,000. Of these, more than 500 have required emergency relocation by the Government of the Canary Islands.
The last eruption in the Canary Islands occurred exactly 50 years after the last time the magma erupted from the Canarian soil (except for the maritime process in El Hierro in 2011): it was the Teneguía, also in the municipality of Fuencaliente. The process began at 4:25 p.m. on October 26, 1971, and lasted until November 18 of that year. It was a relatively short eruption; in fact, it was the shortest of those that have been in the Canary Islands. On that occasion, the lava did not affect the populated areas. In fact, since the volcano is located just to the south of the island, on the coast, the lava was poured almost entirely into the sea, which increased the surface of the island by about two million square meters.
The Teneguía was, fortunately for the inhabitants of the time, the third shortest eruptive process in modern history, surpassed only by two that occurred in Tenerife in the seventeenth and twentieth centuries. Nothing to do with the 2,055 days (about six years) that the eruption lasted in the 18th century in what is now the Timanfaya National Park, in Lanzarote.
The lava delta grows
The Cumbre Vieja volcano, like the rest of the historical eruptions, has created lava deltas upon reaching the sea. The second that has formed this process has already extended the surface of the island by five hectares above the sea and reaches up to 350 meters away from the coastline. To this new insular surface is added that of the other lava delta formed south of the coladas, which occupies 43.46 hectares above the ocean, according to the data provided by the spokesperson for the technical committee of the Canary Islands Volcanic Emergency Plan (Pevolca), Miguel Ángel Morcuende.
Given the relative stability of the volcanic eruption in the last hours, the main concern of Civil Protection is now focused on the rains that are announced for Friday throughout the island, where 60 liters per square meter are expected in twelve hours and up to 15 liters in an hour.