Factors controlling the morphology of monogenetic basaltic volcanoes: the Holocene volcanism of Gran Canaria (Canary Islands, Spain)

Abstract

A detailed morphometric analysis was performed on the 24 Holocene eruptions of Gran Canaria, a nearly circular island located at the centre of the Canary Islands (Spain), developed as result of the eastward movement of the African plate over a mantle hotspot. Rigorous field work was carried out to generate a palaeogeomorphological reconstruction of the Holocene eruptions of Gran Canaria to obtain pre- and post-eruption digital terrain models (DTMs). These eruptions were of Strombolian monogenetic basaltic volcanism style. With respect to the cones, feeder fissures determine their location and some morphological features as crater openings which are usually perpendicular to the slope direction. In addition, the trade winds influence the final volcanic edifice shape and the extent of the pyroclastic sheet-like fall deposits. For the lava flows, the most significant controls are the eruption rate, affecting the maximum distance travelled, and the gully slope and shape that condition their flow path. Concerning volcanic hazard and risk assessment, the applied methodology has led to a better understanding of the recent eruptions and foresees the location and nature of future eruptions.