The 2011 eruption of Nabro volcano: a retrospective analysis through the combined use of satellite data and lava flow modelling
Abstract
The first historic eruption of Nabro volcano (Eritrea) occurred in June 2011. The eruptive event is important for the extraordinary quantity of SO2 emitted into the atmosphere, the extent of the long lava flow emplaced by the eruption and the significant human impacts that ensued notwithstanding the low population density of the Afar region. Because of its remote position, little was known about this eruption regarding the quantity of volcanic deposits and the timing and mechanisms of their emplacement. Here we combined satellite remote sensing techniques and numerical simulations to estimate the volume of erupted products and to reconstruct the dynamics of the lava flow emplacement. The total volume erupted was derived by differencing pre and post eruptive digital elevation models (DEMs) obtained from Aster data. Using the MicMac ASTER (MMASTER) package, we produced multiple pre and post eruptive topographies that were accurately co-registered to minimize misalignment errors. The total volume of deposits, calculated from topography difference by integration of the thickness distribution over the area covered, is more than 600 × 106 m3, of which over 300 × 106 m3 is the volume of the main lava flow that advanced eastward beyond the caldera. The main lava flow was approximately 18 km2 in area and about 17.5 km in length. Optical and thermal observations indicate that the main lava flow had travelled to close to its maximum extent within about 3 days of the eruption onset on 12 June. In addition, most of the tephra was emplaced within about 6 days of the onset. The comparison of time-averaged discharge rates (TADR) obtained from MODIS and SEVIRI data and Supply Rate (SR) derived from SO2 flux data allowed us to estimate the amount and timing of the main lava flow field growth. Finally, the time-varying estimates of the satellite-derived TADR (up to 4 times per hour by SEVIRI data) were then used as input of MAGFLOW lava flow emplacement model, allowing effective simulations of the advance rate and maximum extent of the main lava flow. The simulated lava flows were in good agreement with the actual, mapped lava flow field.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.V51D0138D
- Keywords:
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- 4316 Physical modeling;
- NATURAL HAZARDSDE: 8485 Remote sensing of volcanoes;
- VOLCANOLOGYDE: 8488 Volcanic hazards and risks;
- VOLCANOLOGY