Near-real-time forecasting of lava flow hazards during the 12-13 January 2011 Etna eruption

Abstract

Forecasting the lava flow invasion hazard in near‐real time is a primary challenge for volcano monitoring systems. The paroxysmal episode at Mount Etna on 12–13 January 2011 produced in ∼4 hours lava fountains and fast‐moving lava flows 4.3 km long. We produced timely predictions of the areas likely to be inundated by lava flows while the eruption was still ongoing. We employed infrared satellite data (MODIS, AVHRR, SEVIRI) to estimate in near‐real‐time lava eruption rates (peak value of 60 m3 s−1). These time‐varying discharge rates were then used to drive MAGFLOW simulations to chart the spread of lava as a function of time. Based on a classification on durations and lava volumes of ∼130 paroxysms at Etna in the past 13 years, and on lava flow path simulations of expected eruptions, we constructed a lava flow invasion hazard map for summit eruptions, providing a rapid response to the impending hazard. This allowed key at‐risk areas to be rapidly and appropriately identified.

A year of lava fountaining at Etna: Volumes from SEVIRI

“…Fit results are given in Table 2. In achieving these fits, we use an assumed lava flow thickness set from field measurements for lava flow units emplaced during lava fountains at Mt Etna [see Harris and Neri, 2002;Calvari et al, 2011;Vicari et al, 2011]. These studies indicate that a thickness of between 1 m and 2 m .…”

“…The recent availability of mid-and thermal-infrared data at a frequency of 15 minutes from geostationary platforms, such as GOES, MTSAT and Meteosat Second Generation, have allowed the construction of lava discharge rate time series during such short-lived fountain-fed effusive events [Bonaccorso et al, 2011a;Calvari et al, 2011;Gouhier et al, 2012;Vicari et al, 2011]. The same time-series can be used to yield volume and intensity, with the continuous presence of the satellite sensor in a fixed-position geostationary orbit meaning that data are always available for the targeted location.…”

“…As a result two methodologies have been applied to extract time averaged discharge rates (TADR) and volumes from geostationary satellite data. The first, as applied to SEVIRI data for Etna's 11-13 January 2011 event by Vicari et al [2011], used the spectral-radiance-to-TADR conversion of Harris et al [1997] to obtain event intensity and volume, a method that boils down to an empirical conversion between active lava area and TADR [Wright et al, 2001;Harris et al, 2007a;Harris and Baloga, 2009]. The second was also applied to SEVIRI data for Etna's 11-13 January 2011 event by Gouhier et al [2012] and used the approach of Yokoyama [1957] to convert the total heat liberated by the lava during cooling (E, in Joules) to the mass or volume of lava required to generate that quantity of heat.…”

A method for multi-hazard mapping in poorly known volcanic areas: an example from Kanlaon (Philippines)

“…This step is used to determine and characterize reference eruptions of the volcano, e.g. in terms of explosivity (Newhall and Self, 1982) and/or eruption rate, duration and volume of the lava flows (in the case of mainly effusive volcanoes; Crisci et al, 2010;Vicari et al, 2011). Then, event trees can be created and used as a support tool to structure the quantification of each phenomenon and their frequency of occurrence (Newhall and Hoblitt, 2002).…”

“…Similar definitions are commonly used in the field of risk assessment (e.g. Vecchia, 2001;Douglas, 2007;Crisci et al, 2010;Vicari et al, 2011) and elsewhere (IPCC, 2012).…”