The 2019 Explosive Eruption of Raikoke Volcanic Island, Kuriles: Pyroclastic Deposits and Their Impact on the Relief and Ecosystems

Grishin S. Yu., Belousov A. B., Belousova M. G., Auer A., Kozyrev I. A.

В журнале Journal of Volcanology and Seismology

Год: 2021 Том: 15 Номер: 6 Страницы: 387–398

A short-lived but violent explosive eruption occurred on the small volcanic island Raikoke in June 2019 (central Kuril Islands). The culmination of the eruption lasted 3.5 h and the ash cloud rose to a height of 13 km. An analysis of a sequence of satellite images in combination with ground-based observations gave information on the pyroclastic deposits of the eruption and allowed us to estimate the associated impact on the island ecosystems. We found that this eruption had a phreatomagmatic, sub-Plinian to Plinian character. The phreatomagmatic mechanism of the eruption occurred due to interaction between the rising basaltic andesite magma and ground waters, which were mostly represented by sea water that percolated through the permeable rocks of the volcanic island. The eruption produced numerous pyroclastic flows. The hot deposits of the pyroclastic flows and tephra covered the entire island, destroying the vegetation and the habitat of birds and sea mammals. Much of the pyroclasts was deposited in the form of fans of pyroclastic flows at the base of the volcanic slopes, considerably displacing the shoreline seaward. As a result, the island area increased by 15%. The pyroclastic deposits were intensely eroded and redeposited during the first year after the eruption, making new areas of the island coast. The recovery of Raikoke’s ecosystems will be enhanced by erosion of the pyroclastic deposits and gradual resettling of birds, which would bring new plant species to the island. The succession would be accelerated by areas of survived vegetation. Overall, we see periodic dramatic disruptions in the island ecosystems caused by violent explosive eruptions with subsequent rapid recovery that with high probability will be interrupted by new eruption.

DOI 10.1134/S074204632105002X