After 18 days of volcanic activity, the lava has washed away a total of 421.93 hectares of the Aridane Valley, 1.81 more than in the last day and 153.93 more than a week ago. 21.13% of the area affected by the passage of the wash (93.4 hectares) was dedicated to different crops such as bananas (35.6 hectares, about 73 bushels), vineyards (32.9 hectares) or avocado (6.7 hectares). The lava tongue has reached a maximum width of 1,250 meters. During the last hours, the lava threatened to expand towards the north of the Todoque mountain and towards the Camino de la Gata, but it was paralyzed in both enclaves, as happened with the lava that emanated north after the collapse of the building volcanic on Sunday. The data on the number of buildings affected have not been updated due to the reduced advance of the magmatic material, with which the Volcanic Emergency Plan of the Canary Islands (Pevolca) maintains the number of houses destroyed by lava at 605 and agricultural farms in 58.
The emission centers of the main crater are still active, as well as those located on the sides of the cone, and the appearance of new foci in the vicinity of the eruption is not ruled out. In addition, since Monday an area of fissures located 100 meters northwest of the main mouth has been observed, through which gases emanate and keep the soil temperature very high. The morphology of the cone continues to live stages of growth, due to the accumulation of lava and ash, and decrease, when it collapses due to the weight of the accumulated material. As usual in Strombolian fissure eruptions, effusive phases are alternating, in which large amounts of magma, and explosive phases of low and moderate intensity. According to the Volcanic Explosivity Index (VEI), the Cumbre Vieja volcano maintains a value of 2, on a maximum scale of eight.
Seismicity has been anchored in the area where the greatest activity was detected in the days before the volcano was born and the population of Fuencaliente and Villa de Mazo has been able to feel several tremors. The number of observed earthquakes has decreased in recent hours and their magnitudes have also moderated. The most intense shock that occurred yesterday was 3.7 and was perceived with intensity III in Fuencaliente. The current level of seismicity indicates that more felt tremors may occur, which may cause small landslides in sloping areas. The technical director of Pevolca, Miguel Ángel Morcuende, wanted to reassure the population of the municipalities affected by the seismic activity and pointed out that no significant problems of deformations have been detected in the land and that only land deflations have been confirmed, an aspect which he described as positive.
Ash at the airport
The concern of the Pevolca scientific teams is now focused on the meteorology. A decrease in the height of thermal inversion is expected, from 1,200 to 900 meters, and an increase in stability at low levels of the atmosphere. These factors, together with the prevailing breeze regime on the west coast, are unfavorable conditions from the point of view of air quality. The eastern and northern slopes of the island will be the most affected by the fall of ash, with which the operation of La Palma Airport may be affected. Given this circumstance, the airline Binter has temporarily canceled the flights scheduled for today with La Palma.
The change in the wind regime will lead to a problem of suspended particles that will worsen the quality of the air. So far, concentrations of particles less than 10 microns (PM10) and carbon dioxide (CO2) have been pointed out, but, according to the spokeswoman for the Pevolca and regional director of the National Geographic Institute (IGN), María José Blanco, “has not posed a risk to the population.” Likewise, he explained that work is being done to collect data on air quality and in the coming days a campaign will begin to measure hydrochloric acid (HCl) in the potentially affected populations by the marine plume, which is produced by the thermal shock of the lava with the sea. Since the beginning of the eruption, the island’s air quality surveillance network has been strengthened thanks to the incorporation of two mobile stations in Los Llanos de Aridane and El Paso, with which the level of sulfur dioxide is monitored ( SO2) and the presence of PM10, the main pollutants emitted by the volcano.
The volcano plume maintains a “powerful” SO2 emission, but none of the measurement stations have exceeded the risk parameters for the population
The volcano emitted 2,849 tons of SO2 yesterday, although this value “is underestimated” with respect to the real one. Blanco specified that this is due to the inability to completely bypass the volcanic plume. The CO2 emission associated with the Cumbre Vieja area –measured on Sunday– reaches a value of 1,650 tons per day. The volcano plume maintains a “powerful” SO2 emission (5,849 tons per day), but in none of the measurement stations have exceeded the risk parameters for the population. The eruptive process, Blanco pointed out, can show episodes with a pulse of phreatomagmatic activity and the height measured yesterday of the ash and gas column was 3,000 meters.
One of the dangers derived from the eruption is the accumulation of ash on the roof of the houses near the emission source. When the tasks related to safeguarding the lives of people and animals are finished, the fire crews of Gran Canaria carry out preventive cleaning tasks on the roofs and rooftops to prevent them from collapsing due to the weight of volcanic dust, which is around the 100 kilos per square meter, and you inspect the structures. These teams spend between eight and ten hours uninterrupted removing ash and can lose between one and two kilos each day due to effort and loss of fluids through sweat. To this is added the complicated conditions under which they carry out their work, due to the ash rain that irritates the eyes, the skin and the respiratory tract, circumstances that force them to work protected with special masks.
The strip formed by the accumulation of lava that reaches the coast already has an area of 38 hectares and is expanding in a north-south direction.
The fajana formed by the accumulation of lava that reaches the coast already has an area of 38 hectares and expands in a north-south direction. The marine plume remains along the edge of the lava delta, producing clouds of water vapor and Hcl, which are concentrated in a small volume around the contact. The effect of the fajana on the water column of the marine environment in some physical-chemical and biological parameters reaches depths of 250 meters and a distance of 500 meters from the front of the delta.
Morcuende reported that currently 214 people are staying at the Princess Hotel in Fuencaliente, five more than on the previous day, which «is fundamentally due to the fact that we are already beginning to have long-term processes of relationships with friends or family, so we are in the face of strictly a matter of personal relationships ».
Yesterday the portable desalination plants arrived in Puerto Naos that will supply water to the farmers affected by the breakdown of the irrigation systems and will allow them to maintain their plantations until the supply can be restored in the west of the island. For the installation of these complex infrastructures, it was necessary to move a convoy made up of four trucks with four-by-four traction and a special crane to unload the merchandise. A team of ten people participated in the operation, a cleaning device to condition the roads, make it possible to take advantage of the gutters and avoid skidding, and a police escort. For his part, Ministry for Ecological Transition has confirmed the charter of a tanker, which will allow a substantial increase in the flow of water for irrigation and which is expected to reach the island next week.