We cannot prevent volcanoes from erupting, and we cannot yet travel inside them like French sci-fi author Jules Verne once envisioned. JJ Coello Bravo, Author provided Forecasting volcanic activity Similar changes could be monitored as a signal of eruption wind-down in future eruptions around the world.Įarly lavas from the 2021 La Palma eruption were voluminous and blocky, acting as a hot ‘bulldozer’ (September 22 2021, traffic sign for scale). We also found a key change in lava chemistry about two weeks before the eruption ended, which suggests cooling of the magma due to a dropping magma supply. This included a change from thick lavas that acted as a bulldozer at the start of the eruption, to runny lavas that created rapid lava rivers and lava tunnels later in the eruption. Using the laser-powered method, we could see variations in lava chemistry linked to changes in earthquakes and sulphur dioxide emissions, as well as eruption style and the resulting hazards. These are precious samples as we know their exact eruption day, and many of the sampling sites are now covered by later lavas from the eruption. We analysed lava samples collected systematically by our collaborators in Spain throughout the three months of eruption. Instituto Geologico y Minero de Espana, Author provided It destroyed more than 1,600 homes, forced the evacuation of more than 7,000 people and generated losses of more than €860 million (AU$1.4 billion).ĭrone image of a lava flow from the 2021 La Palma eruption (December 4 2021, houses for scale). Our study focused on the 2021 eruption at La Palma, the most destructive volcanic eruption on historical record in the Canary Islands.įrom September to December 2021, a total of 160 million cubic metres of lava covered more than 12 square kilometres of land. The 'pulse' of a volcano can be used to help predict its next eruptionĪ destructive disaster in the Canary Islands

Even if we call the crystals “large”, they are often as small as a grain of salt (or up to a chickpea in size if you are lucky!) and difficult to remove. This provides a faster and more detailed measure of melt chemistry and its evolution over time, compared to traditional analysis of the entire rock, or to painstaking separation of matrix and crystal fragments from crushed rock samples. The method allows for a rapid chemical analysis. We then analysed the laser-generated particles by mass spectrometry to determine the chemical composition of the volcanic matrix. To isolate the melt signal, we used an ultraviolet laser, similar to the ones used for eye surgery, to blast the rock matrix between larger crystals. However, the crystals can get in the way when we want to focus on the melt that carries them to the surface, and how the melt properties vary throughout the eruption. The crystals formed in the guts of the volcano are excellent archives of the run-up to eruption. MacDonald, Author providedĪs a result, volcanic rocks can look a bit like “rocky road” chocolate. The image is in cross-polarised transmitted light (5mm scale bar). Microscope view of lava erupted on Octoat La Palma, with large colourful crystals in a fine-grained black rock matrix which we analyse via laser.

Volcano eruption canary islands