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Temporal and Spatial Evolution of Cabeza De Vaca 2021 Rift Eruption (Cumbre Vieja Volcano, La Palma, Canary Islands) From Geophysical and Geodesic Paramethers Analyses

Description: 

The 2021 Cabeza de Vaca eruption is the most recent, damaging, and long-term eruption since historical records at La Palma, Canary Islands. The eruption produced lava flows and tephras (VEI 3) from several lava fountain with Strombolian and Vulcanian phases. We analyzed several geophysical parameters (seismicity, surface deformation, thermal anomalies, volcanic activity) with the aim to reconstruct the temporal development of the magma plumbing system. The eruption was accompanied by an intense seismic swarm and surface manifestations of activity. The earthquake catalogue includes over 9000 events, the largest with magnitude 5.0 (mbLg). The seismic sequence can be grouped into nine distinct phases, which correspond to well-separated spatial clusters and distinct earthquake regimes. A strong premonitory thermal anomaly was calculated on July 2021 at the South of La Palma, according to the seismicity pre-eruptive phase 1. The source of the magmas was between 40 and 20 km depth, according to a prolonged magmatic storage withing the upper mantle. The second source of seismicity is located at depths < 15 km, suggesting a short-term stagnation of basanitic magmatic system within the lower crust, near the Moho. These earthquakes outline delineating the magma pathway. In phases 2 and 3, just before and immediately after the beginning of the eruption, the seismicity in the mantle disappears completely, reappearing ten days after the eruption started. In both phases, the most superficial activity is registered in the shallow crust and coincides temporarily with the disappearance of deep seismicity. The pattern of deformation began before the eruption with a breakpoint around September 11, after which, deformation accelerated sharply followed by a stabilization in phase 3 and a decrease in following phases. The level of deformation never came back to the original background, suggesting that a shallow magma intrusion was stablished.

Session: Seismology's Role in Assessing Volcanic Hazard at Multiple Time Scales

Type: Oral

Date: 4/18/2023

Presentation Time: 08:30 AM (local time)

Presenting Author: María Belén Benito Oterino

Student Presenter: No

Invited Presentation: 

Authors