Image Credit: G.KERESZTURI Calculating our size- a new volume estimate for the AVF A highly specialised systematic volume estimation model has been developed for use in New Zealand’s Auckland Volcanic Field (AVF). In the calculations, a basaltic monogenetic volcano has been categorised into six parts. The volume of subsurface portions – such as “pipes” (diatremes) beneath phreatomagmatic (explosion crater style) volcanoes – have been inferred using geometrical considerations, based on exposed analogue volcanoes. Positive volcanic landforms – such as scoria/spatter cones, tephra rings and lava flows – have been defined via a Light Detection and Ranging (LiDAR) survey-based Digital Surface Model (DSM). The volumes of outer (distal) tephra – associated with explosive eruptions – have been determined using published relationships that relate the original crater size to eruption volumes. Utilising only the highly reliable volume estimates, the overall magma output – converted to a dense rock equivalent – for the AVF is a minimum of 1.704 km3, with lava flows making up the biggest component. Tags:Auckland Volcanic FielddiatremeLiDARmagmaphreatomagmaticpublications
