2018/09/11 by A. Hildenbrand, F.O. Marques, João Catalão · 41 citations
Earth and Planetary Sciences · #earthquake and tectonic studies #Geology and Paleoclimatology Research #Geological and Geophysical Studies #Mass wasting #Wasting #Volcano #Scale (ratio) #Geography #Biology #Cartography #Paleontology
paper · pdf · doi:10.1038/s41598-018-32253-0
published in Scientific Reports 8(1), 13898 (Nature Portfolio)
openalex publication_date 2018/09/11 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/23
Small intra-plate volcanic islands (total height above seafloor <2500 m) have been considered gravitationally stable. Topographic, stratigraphic, structural and new K/Ar data show that the small island of Flores (Azores) is strongly asymmetric and made up of nested volcanic successions. Along the northwestern coastline, ca. 1.2 Ma lava flows are in lateral contact with a younger volcanic unit (ca. 0.7 Ma), reflecting the existence of a steep lateral discontinuity. From the general dip of the lava flows, their age and the arcuate geometry of the contact, we infer a major landslide that removed the western flank of the older volcano. Further inland, E-dipping lava flows at the summit of the island are ca. 1.3 Ma, suggesting another landslide structure that displaced the whole western half of the former volcanic edifice. Available offshore data show a large hummocky field west of Flores, here interpreted as voluminous debris-avalanche deposits. Unlike the eastern and central Azores islands, Flores sits on a relatively stable tectonic setting. Therefore, we propose that small-size volcanic islands can be sufficiently gravitationally unstable to experience recurrent episodes of large-scale mass wasting triggered by mechanisms other than tectonic earthquakes and thus represent an under-evaluated potential source of hazard and, therefore, risk.