Eruption of Nyiragongo in DRC: "We were lucky to have a lava flow which stopped at the gates of Goma"
Audio 02:08
The lava flow caused by the eruption of the Nyiragongo volcano fortunately stopped at the gates of Goma this Sunday, May 23, 2021. via REUTERS - MONUSCO
Text by: David Baché
6 mins
The Nyiragongo volcano, near Goma, in eastern DRC, no longer seems threatening.
The volcanologist Benoît Smets looks back on this eruption which took everyone by surprise, even if we knew that this volcano could erupt one day or another
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The lava flow stopped
just before arriving in the city
.
Yesterday evening, its unexpected eruption threw the inhabitants of Goma on the roads, the populations fled out of the city and even to neighboring Rwanda.
Panic movements have caused accidents, several deaths are to be deplored, the official record is being consolidated.
Benoît Smets is a researcher at the Royal Museum for Central Africa in Tervuren and professor at the University of Brussels.
For the past fifteen years, he has been working on the volcanoes in the area, particularly Nyiragongo, in collaboration with the Goma Volcanological Observatory.
There were no warning signs that told us that there was going to be a big change in Nyiragongo.
It should be known that these are volcanoes - both
Nyiragongo
and its neighbor, Nyamuragira - which show clear precursor signs, as seen in seismicity, in earthquakes, generally a few tens of minutes or a few hours before l 'eruption.
And so we didn't really have any clear signs, which took us by surprise.
We didn't expect it at all.
And what are these signs that did not appear?
For example, the characteristic of Nyiragongo is that it has a lava lake in its main crater and one would have expected to have extremely violent variations of this lava lake, seismic activity associated with the lava lake and can -be tectonic earthquakes, therefore brittle earthquakes, with felt magnitudes, which would arrive before the eruption.
And there, in fact, this kind of seismicity rather happened afterwards.
So it seems that there really was a surface eruption and then a deeper seismic activity, with a contribution of magma, but that is not yet confirmed, since we just have automatic results.
Detailed analyzes of the seismic measurements have not yet been made
.
And from what we could see, it could have been worse?
Already, the fact that there were no large precursors, says that it is probably not a major eruption either, as we had in January 2002. The configuration of the length of the lava flow.
What happened is more like what we had in 1977. It's an eruption which is a little less violent.
I think we were lucky to have a lava flow that stopped at the gates of Goma.
Even if it unfortunately invaded inhabited areas, it was still limited to the northern part of the city and it did not return to the city center, where there, the damage would have been much more substantial
.
And for the rest, what can we expect?
That's a good question, because we only know of two historical eruptions of volcanoes, in 1977 and 2002. We now have a case that seems slightly different, so it's difficult to interpret.
From what we can see now, I don't think we would have any surface activity again.
On the other hand, the seismic activity at depth continues.
So we do not yet know exactly what is happening, we will have to analyze this activity in detail.
But a priori, I would say that the eruption on the surface is over.
► To read also: Eruption of Nyiragongo in the DRC: the city of Goma spared, the inhabitants are returning little by little
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