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Hazards and Havoc: Recent Eruptions on La Palma Island, Canary Archipelago
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Isaac E. Pope
n a world dominated by quiescence, it is the erratic disruptions in the landscape that demand attention, yet few have created such unremittent surprises of late as the recent eruptions on La Palma Island. Located in the Canary Archipelago off the coast of Morocco, La Palma Island developed from the steady turmoil typical of oceanic hotspot island chains. Nonetheless, the erratic volcanic history of the archipelago seemed to suggest that eruptions are few and far between though dangerous in the extreme. Naturally, the identification of growing unrest beneath the Cumbre Vieja rift zone on La Palma’s southern limits from 2017 to 2020 led researchers to conclude it was a warning “most likely decades before a potential eruption” (Fernandez et al., 2021), yet this was merely the rising curtain before the main act. Beginning in September 2021, fissure eruptions released basaltic lavas across the countryside, continuing the intricate volcanic history of the archipelago. Even so, the eruptions on La Palma Island are but the budding expressions of a long, luxurious history of volcanism.
The Canary Archipelago: A Luxurious History The saga of volcanism in the Canary Archipelago rests upon a backdrop stretching to the breakup of Pangea (Troll and Carracedo, 2016a). As rifting sliced through Pangea, a series of basaltic eruptions fed by the upwelling mantle produced an extensive large igneous province in Jurassic time. Since then, continued decompression melting led to the development of a hot spot which fed a series of submarine volcanoes along the rigid passive margin of the African Plate. Though speculation abounds on the exact nature of the hot spot (van den Bogaard, 2013), its effects have remained consistent in the region, as evidenced by the Canary Archipelago, yet even the obviousness of its extreme duration is perhaps a greater mystery than the hot spot itself. Indeed, the Canary Archipelago and Hawaiian Islands are, for all intents and purposes, nearly identical except in one detail: their age. The oldest Hawaiian Island still above sea level is dated at nearly 5 Ma, while the oldest island in the Canary Archipelago is dated as four times older at 20 Ma (Carracedo, 1999). The immense volume of the shield volcano gently warps the adjoining oceanic lithosphere, and the volcanic islands gradually subside and eventually become seamounts. Many oceanic island chains have ages similar to that of the Hawaiian Islands, yet it appears the curious ancientness of the Canary Archipelago may be due indirectly to the rifting of Pangea. Some geologists have proposed that the rigid passive margin of Africa may be helping to offset the subsidence of the Canary Archipelago, allowing individuals islands to remain above sea level for as Figure 1. Located off the western coast of Morocco, the Canary Archipelago resulted from an intricate volcanic history stretching back to Jurassic time. As the westernmost and youngest member of the Canaries, La Palma Island and its various mapped volcanic centers provides a window into oceanic hotspot volcanism. Note that each historic eruption has been sourced from novel fissures, as is the case of the 2021 (not mapped) eruption along the Cumbre Vieja Rift Zone. Produced after Fernández et al. (2021).
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AEG NEWS 64(5)
Winter 2021
