ESA Sentinel 1 and 2 captured a new lava flow inside the crater at Nyamulagira since January 27-31 2020.
The flow originates from the pit crater located in the NW part of the main crater and fills the large trough located to the SW part of the crater. This new flow is however not related to a recent change of activity at Nyamulagira as attested by the absence of modification in the seismicity, degassing or ground deformation patterns. It is only the result of the overflow of the pit crater that started filling up following the last eruption (see background section below).
Animated gif of coherence from Sentinel-1 radar interferometry. When the lava flows, coherence is lost, changing from white to black colour along its path.
Background : At the end of the last eruption at Nyamulagira (November 2011 to April 2012), the pit crater progressively collapsed during more that a year. Lava fountains appeared at the bottom in April 2014 (Smets et al. 2014), ultimately forming a lava lake. Since then, and mostly since beginning of 2018, the lava lake level rose, filling the crater progressively.
Ref: Smets, B., N. d’Oreye, and F. Kervyn (2014), Toward Another Lava Lake in the Virunga Volcanic Field? EOS Trans. AGU.