Researchers from Kiel and Spain want to investigate the effects of the longest known volcanic eruption in the history of the Canary Island of La Palma. At the beginning of January, a team from several institutes on board the research ship "Maria S. Merian" mapped the seabed off the island, project manager Jacob Geersen from the University of Kiel told the German Press Agency. In three days it was possible to measure most of the western side of the island.

The researchers hope that the data will provide insights into the changes in the structure of the volcano caused by the eruption at the end of 2021 - experts also speak of volcanic structures. It erupted on September 19, 2021 and caused immense damage. At least 7,000 people had to be evacuated and 3,000 were unable to return. Plantations for bananas, the island's main produce, were also buried by the lava.

"The eruption lasted almost three months and the area covered by the new lava is more than 10.5 square kilometers," said marine geophysicist Geersen from the Institute of Geosciences at Kiel University.

Outlines of the volcano flank are to be examined

"Hundreds of thousands of earthquakes, a lava flow up to 190 meters thick, as well as vertical land uplift and subsidence in the meter range were caused by the migration of hot lava underground," said project partner and marine geophysicist Felix Gross from the Center for Ocean and Society at Kiel University. Because there was hardly any high-resolution data from the marine part of the volcano's flank, the "Sub:Palma" expedition hydroacoustically mapped the west side of the island. They want to compare their data with the results of deep-sea investigations from the late 1990s.

The researchers also want to examine the exact contours of the volcano flank. "As for the flank of the volcano, geodetic and geological data on land indicate that it is slowly sliding into the Atlantic," said Gross. "So far, however, neither the size of the moving flank part is known, nor where the boundaries run from the unstable to the stable part of the volcanic edifice."

Researchers from the GEOMAR Helmholtz Center for Ocean Research in Kiel and two Spanish institutes were also involved.