Nyiragongo volcano (DR Congo): fears of potential catastrophic eruption trigger partial evacuation of Goma City

Authorities are highly concerned about the risk of a second - potentially more destructive if not catastrophic - eruption from the volcano in the near future and have ordered the partial evacuation of Goma, where a mass exodus seems to have started, making the overall situation even more chaotic and difficult.
The reason scientists worry are both a lack in precise monitoring data, the potential of large impact of an eruption, and the continuing earthquakes that rattle the area around Goma and Gyseni, as well as ground cracks in and around Goma, which might indicate that magma is accumulating beneath the area and could well lead to a new eruption.

More than 200 tremors have been recorded in the past 2 days. According to some unconfirmed posts on social media, some of the new ground cracks expose glow beneath (likely from hot gasses if true).

According to latest findings of researchers, the recent eruption indeed drained the lava lake, but according to some sources, it has already partially refilled (or did not drain entirely).
Ash plumes are rising from the crater of the volcano, likely from internal collapses after the (partial?) drainage of the lava lake. Combined with the intense degassing activity, they create dangerously contaminated acid rain and people are urged not to use rain water for cooking, washing etc if any possible.

From a summary on reliefweb:
"Researchers observing the volcano have a limited sense of the current risk level; the situation remains highly unpredictable as several warning signs emerge of the risk of a new eruption in the next few days, including multiple cracks on the ground, emission of gas and the worrying fact that the Kivu crater seems to have refilled very quickly, indicating another possible eruption. The IRC is preparing a response to meet the escalating humanitarian needs in collaboration with the government and other NGOs. There is now a desperate need for an increase in funding through support from the international community."

There are several scenarios how the situation might evolve (adapted from Nyiragongo : de 3 scénarios présentés par l'OVG, une prochaine éruption du volcan est inévitable):

Scenario 1:
A new eruption of Nyiragongo on its southern flank, where fractures open in the area of Goma and Gisenyi cities. Lava flows would likely destroy destroy part of them.

Scenario 2:
An eruption of Nyiragongo volcano on its southern flank, but with fissures INSIDE the city and extending close to Kivu lake. Large volumes of lava destroy part of the cities of Goma and Gisenyi and reaches the lake. The amount of lava that would flow into the lake is insufficient to raise the temperature of the deep water over the entire lake by at least 1° C, there will be no lake overturn and eruption of deadly dissolved CO2 from the gas-rich deep-lake water.

Scenario 3:
An eruption of Nyiragongo volcano opening of fractures on its southern flank inside the city and/or inside the lake Kivu. Parts of Goma and Giseny would be destroyed and the heat released by lava in the lake would trigger an overturn of the deep lake water rich in dissolved CO2. This would cause a catastrophic overturn and sudden release of large quantities of CO2, a so-called limnic eruption. The gas cloud would instantly kill all people and animals at lower elevations around the lake - likely thousands of people.
The same could be triggered if a very large earthquake was to occur under the lake sufficiently disturbing the water layering...
While this is the worst scenario, it is hopefully also the least likely.

Scenario 4:
No eruption occurs. Seismic activity gradually dies down, as it is a result of internal readjustments after the recent eruption.

A pall of ash hangs over #Goma on May 25; #Nyiragongo is obscured by plume/clouds. Source of ash unclear but possibly from collapses within the Nyiragongo crater after #lava lake drainage. @CopernicusEU #Sentinel3 OLCI True Color @planet PlanetScope image of Goma-Gisenyi pic.twitter.com/sdl3PY8crs

— Simon Carn (@simoncarn) May 25, 2021

Volcan Nyiragongo: risque de catastrophe majeure, exode pour fuir Goma | TVA Nouvelles https://t.co/Ge8rmabGf2

— SIBOMANA Jean Bosco (@sibomanaxyz987) May 27, 2021