Analyzing the 2011 eruption of Nabro volcano using satellite remote sensing and numerical modeling of lava flows

The 2011 eruption of Nabro volcano, situated at the southeast end of the Danakil Alps in Eritrea, has been the first historical on record and one of the largest eruptions of the last decade. Due to the remote location of the Nabro volcano and the lack of data from ground monitoring networks at the time of the eruption, satellite remote sensing gives the first global view of the event, providing insights on its evolution over time. Here we used numerical modeling and high spatial resolution satellite data (i.e. EO-ALI, ASTER, PlanetScope) to track the path and velocity of lava flows and to reconstruct the pre- and post-eruptive topographies in order to quantify the total bulk volume emitted. High temporal resolution images (i.e. SEVIRI and MODIS) were exploited to estimate the time-averaged discharge rate (TADR) and assess the dense rock equivalent (DRE) lava volumes constrained by the topographic approach. Finally, satellite-derived parameters were used as input and validation tags for the numerical modelling of lava flow scenarios, offering further insights into the eruption and emplacement dynamics. We found that the total volume of deposits, calculated from differences of digital elevation models (DEMs), is about 580 × 10⁶ m³, of which about 336 × 10⁶ m³ is the volume of the main lava flow that advanced eastward beyond the caldera. Multi-spectral satellite observations indicate that the main lava flow had reached its maximum extent (∼16 km) within about 4 days of the eruption onset on midnight 12 June. Lava flow simulations driven by satellite-derived parameters allow building an understanding of the advance rate and maximum extent of the main lava flow showing that it is likely to have reached 10.5 km in one day with a maximum speed of ~0.44 km/h.