RESEARCH ARTICLE Numerical simulation of basaltic lava flows in the Auckland Volcanic Field, New Zealand—implication for volcanic hazard assessment Gábor Kereszturi & Annalisa Cappello & Gaetana Ganci & Jonathan Procter & Károly Németh & Ciro Del Negro & Shane J. Cronin Received: 21 April 2014 /Accepted: 27 September 2014 /Published online: 15 October 2014 # Springer-Verlag Berlin Heidelberg 2014 Abstract Monogenetic volcanic fields, such as the Auckland Volcanic Field (AVF), New Zealand, are common on the Earth’ s surface and are typically dominated by basaltic lava flows up to 10 s of km long. In monogenetic volcanic fields located in close proximity to human population and infrastruc- ture, lava flows are a significant threat. In this study, lava flow emplacement conditions for some basaltic eruptions of the AVF were reconstructed using the thermo-rheological MAGFLOW model. Eight existing lava flows in the AVF were simulated using MAGFLOW and eruptive volumes measured from Light Detection and Ranging (LiDAR)-de- rived digital terrain models (DTMs). Fitting the simulations to the dimensions of actual lava flows provides insight into their emplacement mechanisms and conditions, such as effu- sion rate, and probable eruption durations. By looking at emplacement in different settings, the likely magma ascent rate for studied AVF eruptions is calculated to have been on the order of 0.1 m/s. In the AVF, the typical estimated duration of past lava flows was from a minimum of 2 days for small- volume flows, such as Little Rangitoto (0.0015 km 3 ), up to 83 days for large volume flows, such as Three Kings (0.078 km 3 ). The three best-fitting simulations were used to establish eruption scenarios for future volcanic hazard map- ping for the AVF. Inferences of eruption duration that will be useful for developing realistic emergency management plans and recovery scenarios for this densely populated volcanic field are also provided. Keywords Lava flow . Effusion rate . Magma flux . Ascent velocity . MAGFLOW . Numerical simulation . Feeder dyke . Scoria cone Introduction The Auckland Volcanic Field (AVF) is a basaltic volcanic field that has been active for the last ca. 250 ky and hosts at least 52 monogenetic eruptive centres (Needham et al. 2011; Kereszturi et al. 2013). Apart from distal tephra fall, lava flows are the most widely distributed volcanic product of the AVF. These lava flows, up to ca. 10 km long, cover much of the metropolitan area of the City of Auckland (~360 km 2 ), which has a population of almost a million and a half people. Depending on their location, future lava flow-forming erup- tions in the AVF have the potential to cause significant social and economic damage. In urbanized volcanic fields, such as AVF (Lindsay et al. 2010), and fields that threaten nearby urban areas, such as Harrat Rahat near Al-Madinah City, Kingdom of Saudi Arabia (Moufti and Németh 2013) and Sierra del Chichinautzin near Mexico City, Mexico (Siebe et al. 2004), a quantitative analysis of the most likely future courses of lava flows is an essential component for risk-based decision making in land-use planning and emergency management. Previous studies of the AVF have mostly focused on deter- mining the location, nature and possible effects of future Editorial responsibility: M. Manga G. Kereszturi : J. Procter : K. Németh : S. J. Cronin Volcanic Risk Solutions, Institute of Agriculture and Environment, Massey University, Private Bag 11 222, Palmerston North, New Zealand A. Cappello : G. Ganci : C. Del Negro Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Catania, Piazza Roma 2, 95125 Catania, Italy G. Kereszturi (*) New Zealand Centre for Precision Agriculture, Institute of Agriculture and Environment, Massey University, Private Bag 11 222, Palmerston North, New Zealand e-mail: g.kereszturi@yahoo.com Bull Volcanol (2014) 76:879 DOI 10.1007/s00445-014-0879-6