Evolution of an active lava flow field using a multitemporal LIDAR acquisition

Abstract

[1] Application of light detection and ranging (LIDAR) technology in volcanology has developed rapidly over the past few years, being extremely useful for the generation of high-spatial-resolution digital elevation models and for mapping eruption products. However, LIDAR can also be used to yield detailed information about the dynamics of lava movement, emplacement processes occuring across an active lava flow field, and the volumes involved. Here we present the results of a multitemporal airborne LIDAR survey flown to acquire data for an active flow field separated by time intervals ranging from 15 min to 25 h. Overflights were carried out over 2 d during the 2006 eruption of Mt. Etna, Italy, coincident with lava emission from three ephemeral vent zones to feed lava flow in six channels. In total 53 LIDAR images were collected, allowing us to track the volumetric evolution of the entire flow field with temporal resolutions as low as ∼15 min and at a spatial resolution of <1 m. This, together with accurate correction for systematic errors, finely tuned DEM-to-DEM coregistration and an accurate residual error assessment, permitted the quantification of the volumetric changes occuring across the flow field. We record a characteristic flow emplacement mode, whereby flow front advance and channel construction is fed by a series of volume pulses from the master vent. Volume pulses have a characteristic morphology represented by a wave that moves down the channel modifying existing channel-levee constructs across the proximal-medial zone and building new ones in the distal zone. Our high-resolution multitemporal LIDAR-derived DEMs allow calculation of the time-averaged discharge rates associated with such a pulsed flow emplacement regime, with errors under 1% for daily averaged values.

Satellite and Ground Remote Sensing Techniques to Trace the Hidden Growth of a Lava Flow Field: The 2014–2015 Effusive Eruption at Fogo Volcano (Cape Verde)

“…Quantitative measurements of the amount of magma intruded within a lava flow field and causing inflation are scant and normally carried out only on a portion of a compound lava flow field [21,[23][24][25][26][27][28]. On pahoehoe flows from Kilauea, a volumetric growth of ten times the initial flow lobe by inflation has been documented [15].…”

“…Preferred pathways develop in the older portions of the liquid-cored flow as the flow advances, and these pathways can evolve into lava tube systems within a few weeks [15]. Inflation combined with flow overlapping causes a slow and mostly undetected expansion of a complex lava flow field, and can result in sudden reactivation of previously stagnating lava flow fronts [3,6,15,[22][23][24].…”

Why Does a Mature Volcano Need New Vents? The Case of the New Southeast Crater at Etna

“…The first activity at the SEC after 5 years of quiescence, in July 2006, occurred from new vents that lay immediately to the SE and downslope of the first pit crater formed in late-2004, but 1 month later the activity switched back to the summit vent of the SEC. The August-December 2006 eruptive period was concentrated at the summit vent, but activity also occurred from new vents and fissures at the SE base of the SEC cone as well as to the west, in the saddle between the SEC and the Bocca Nuova, and at the southern base of the Bocca Nuova Neri et al, 2008;Favalli et al, 2010). The western vents reactivated during the 29 March 2007 lava fountaining episode, but the later paroxysms in spring 2007, especially those of 29 April and 6-7 May, produced activity exclusively from a fissure that extended for a few tens of meters (<100 m) from the summit down the SE flank of the SEC cone.…”

Benchmarking computational fluid dynamics models of lava flow simulation for hazard assessment, forecasting, and risk management

“…Although experiments offer the advantage of well-constrained input parameters and complete documentation of the resulting flow, they are limited in both extent and kinetic energy, and thus cannot simulate the dynamical and rheological range of real lava flows. Technological advances (including lidar, InSAR, and structure-from-motion photogrammetry) now permit accurate measurements of pre-eruptive topography, as well as repeat measurements of flow geometry that could provide near-real-time data on effusion rate, flow extent, and thickness during emplacement (e.g., Favalli et al, 2010;Poland, 2014;Slatcher et al, 2015). Ideally these measurements would be supplemented by corresponding measurements of thermorheological properties using a combination of field and remotely sensed measurements of temperature (thermocouples and thermal imaging; Lipman and Banks, 1987;Patrick et al, 2017) and rheology (samples and video analysis; Cashman et al, 1999;Lev et al, 2012;Soldati et al, 2016).…”