Speaker: Dr. Jane Scarrow, University of Granada, Spain

Abstract
On 19 September 2021, the Cumbre Vieja volcano on La Palma (Canary Islands) erupted after 50 years of quiescence. The eruption lasted 85 days. Tephra covers over 5,500 hectares and volcanic plume heights reached up to 6000 m depositing material mainly in the eastern part of the island. Cone building initiated from a main fissure vent and evolved into discrete eruptive centers with lava flowing to the west and west-southwest. The lava field covers over 1000 hectares and is c. 3.5 km wide and 6.2 km long.

How such eruptions initiate, evolve and ultimately cease are active questions in volcanology. I will present time series whole-rock and mineral chemistry from throughout the eruption, including initiation to paroxysm and finally cessation. Time-resolved geochemistry shows increasing MgO contents and decreasing incompatible element contents, which may reflect changes in melting dynamics or crystal cargo. A jump in geochemical composition on day 7 to 8 of the eruption coincides with the disappearance of resorbed amphibole crystals and the amphibole peak in XRD spectra, as well as with the transition to less viscous lava flows erupting. The geochemical changes also correlate with variations in geophysical monitoring records of real time seismic amplitude measurements. This new data has potential to be applied to forecasting eruptions and evaluating volcanic hazards and associated risks in the Canary Islands and comparable ocean island systems elsewhere.