Bathy-morphological setting of Terceira Island (Azores) after the FAIVI cruise

Abstract

High-resolution morpho-bathymetric data at 1:200,000 scale obtained during the FAIVI cruise (2011) and the resulting geomorphologic map of the Terceira island offshore area (central Azores, Portugal) are presented for the first time. The uneven morphology around Terceira is primarily related to volcanic features, such as linear and cone-shaped eruptive centres and lava flows. Such features are mostly concentrated on volcanic ridges and are aligned along preferential axes, suggesting a strong interaction between tectonics and volcanic processes. The occurrence of active tectonics is also demonstrated by systems of faults cutting the seafloor to the north, east and south of the island. Mapped erosive-depositional features include an insular shelf located at , 150 m water depth (wd), small landslide headwalls, erosive scarps, channelized features and crescent-shaped bedforms. The presented map may represent the base for a first-order geo-hazard assessment.

Morphology of Lipari offshore (Southern Tyrrhenian Sea)

“…A large spectrum of erosive-depositional morphologies ranging at different scales (from tens up to several kilometers in length/width) is observed on the submarine flanks of Lipari. Landslide processes are commonly represented by small landslides affecting the outer edge of the insular shelf and overlying submarine depositional terraces, similarly to that observed for the nearby Stromboli and Vulcano islands (Casalbore, Romagnoli, Bosman, & Chiocci, 2011;Romagnoli et al, 2013a), and at Terceira Island, Azores (Chiocci et al, 2013;Quartau et al, 2014). Clear evidence of large-scale sector collapses are lacking at Lipari, different from that reported in the nearby Stromboli edifice (Romagnoli, Casalbore, Chiocci, & Bosman, 2009a;Romagnoli, Kokelaar, Casalbore, & Chiocci, 2009b), whereas wide translational slides are only present on the submarine flank of the Banco del Bagno volcanic cone.…”

The morphology of insular shelves as a key for understanding the geological evolution of volcanic islands: Insights from Terceira Island (Azores)

“…The submarine topography of Terceira Island is dominated by four volcanic ridges (Figures a and b) [ Chiocci et al ., ; Lourenço , ], (1) the Serreta Ridge (SR) in the west, (2) the ridge that extends NW of the PAV hereafter called Northwest Terceira Ridge (NWTR), (3) the ridge that extends SE of Angra do Heroísmo hereafter called Southeast Terceira Ridge (SETR) and the ridge that extends SE of Praia da Vitória hereafter called East Terceira Ridge (ETR). These ridges are the offshore volcanic and tectonic prolongation of Terceira Island although the onshore‐offshore connections are poorly defined due the differential effect of marine and terrestrial erosion.…”

The insular shelves of the Faial‐Pico Ridge (Azores archipelago): A morphological record of its evolution

“…Consequently, little is known about the shelves surrounding these islands. However, the morphology that results from the imprint of the physical processes over these nearshore features can provide valuable insights on the geological evolution of the islands [ Babonneau et al ., ; Casalbore et al ., ; Chiocci et al ., ; Fletcher et al ., ; Kennedy et al ., ; Mitchell et al ., , 2008; Quartau and Mitchell , 2013; Quartau et al ., , 2012, 2014; Romagnoli , ].…”