Cartografía de alta resolución y caracterización física, geoquímica y petrográfica de los productos de la erupción de 2018 del volcán Fernandina, Islas Galápagos.

Abstract

Fernandina volcano is a pristine, uninhabited island located ~1,200 km west of the coast of Ecuador. Is the westernmost and most active basaltic shield volcano in the Galapagos Archipelago. On 16 June 2018, Fernandina erupted from radial fissures located on the northern flank. The eruption lasted 2 days and lava flows reached the sea in a few hours. Aerial images of the entire lava field were taken with an unmanned aerial vehicle. These were processed and used to map, at high resolution (3 - 8 cm/px), the boundaries and internal structures of the lava field. The lava flow reached a total length of ~4930 m and covered an area of 1.80 km2 with an average thickness of 2.94 ± 1.50 m. The total volume of the deposit is 5.29 ± 2.74 x and the dense volume is 3.32 ± 1.72 x (value obtained from density measurements on rock samples). Petrographic and chemical analysis shows that the rocks are plagioclase-rich tholeiitic basalts whose chemical composition is quite homogeneous (%SiO2 = 48.24 ± 0.26). This allows a longitudinal rheological study based on morphology. Morphological evidence of deposits coupled with volcanic tremor recorded by seismic stations suggests that the lava emission was characterized by at least 4 phases and evolved into a channel-fed ʻaʻā lava flow system.