Nyiragongo Erupts, May 2021


June 3, 2021, 8:01 a.m., Pacific: About an hour ago, the official news source Nyiragongo Info announced that the people ruling North Kivu right now (it’s under military government at the moment because of civil strife in the hills) are allowing people to return to Goma.

Per Twitter translation, the whole thread reads:

In view of the reassuring scientific data recorded in recent days by the OVG, the provincial government of North Kivu is hard at work to organize and / or facilitate the gradual return of the displaced to Goma and in the territory of Nyiragongo.

There was already a spontaneous movement of the population back to these entities. It is now a question of ensuring that this return and resettlement take place under the best possible conditions. The measures taken in this direction will be communicated later.

However, the authorities through the OVG continue to closely monitor and reassess the situation on a daily basis, as a resurgence in volcanic activity cannot yet be completely ruled out for the moment. The population is called to remain attentive and vigilant.

It’s a gamble, nothing more, but realistic: you can’t keep hundreds of thousands of people up in the air, so to speak, through what could be a prolonged period while the Nyiragongo system restabilizes.

That’s even though the stabilization process might mean another eruption, possibly venting through Goma itself this time and/or even under the lake, causing Lake Kivu to explode.

I applaud their courage, sensibility, and leadership (in getting ahead of a population on the move and arranging the best possible conditions for its return).


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But read this paper and Georiska’s updates to see what these Congolese (and possibly Rwandans nearby) face. Sigh.

Here’s Georiska’s report for June 2 (there are excellent photos and graphics here, too):

Seismic data, recorded to date, indicate a continuing decrease in the number and magnitude of earthquakes and magnitude of earthquakes (most of them are not felt); the direction is southward under the lake.

The GPS network still indicates a decrease in the displacement velocities measured at the stations. The physical impossibility of installing seismic or GPS stations in the lake makes it impossible to detect to accurately detect any upwelling of magma beneath the lake.

New satellite data recorded between 27 May and 1 June show that the ground continues to deform south of the town of Goma, albeit at a much slower rate than at the beginning of the eruption. These deformations can still create or extend existing ground fractures in the ground.

New landslides in the crater may cause ash fallout in the surrounding areas.

Overall, the situation is favourable, although a resurgence of activity cannot be completely ruled out. This justifies the continued intensive monitoring and daily reassessment of the situation by the OVG.

Don’t let that word “justifies” stir cynicism. This is what the ground around Nyiragongo is doing, as magma and associated fluids and gases move underground, deforming it:

Source, left; source, right.


That’s INSAR imagery (see video below). The closer the lines are, the more the displacement. And that action is in and around Goma, especially in the eastern parts (which were evacuated).



Unfortunately, INSAR doesn’t work on water, but seismicity shows the dyke just east of and under Goma extending into Kivu (white is old centers, red are from more recent days):


Don’t panic: this is over time, since the eruption began through May 31 and all experts agree that seismicity is far lower now. (Image source)

Let’s hope that this gamble pays off.


June 2, 2021, 7:31 a.m., Pacific: Satellites are helping a little bit:

…[N]ew satellite data recorded between 25 and 31 May underline the absence of deformation on the flanks of Nyiragongo and indicate that the ground continues to deform south of the city of Goma, albeit to a lesser extent than at the beginning of the eruption. These deformations may still create or extend existing ground fractures..,

— Full Georiska report here.

Nyiragongo showed no deformation during a satellite pass 45 minutes, they report, before the eruption on May 22nd.

Volcanoes are tricky. And there is so much life at stake here.


June 1, 2021, 8:50 a.m., Pacific: Per Georiska on the 31st (source of yesterday’s quote, too, by the way):

Current earthquake (seismicity) and ground deformation data continue to indicate the presence of magma under the urban area of Goma with an extension under Lake Kivu. Although there are still earthquakes recorded, their energy is globally lower. Their location and the direction of the GPS displacements still indicate a halt or pause in the propagation of the magma intrusion towards the south. A decrease in displacement velocities measured by the GPS network still seems to confirm these observations. The physical impossibility of installing seismic or GPS stations in the lake makes it impossible to accurately detect any upwelling of magma under the lake.

Per environmental experts in Rwanda — which gets almost 10% of its power from mining Lake Kivu, per this 2019 video (segment starts around 6:03) — the lake is stable.

The Virunga National Park Twitter account sums up the general lay view quite succinctly:


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If lay opinions are worth anything, here’s mine: the farther we get from that May 22nd eruption, the less likely a limnic eruption becomes.

This time.

From that article, it looks to me like Rwanda based its claim purely on lake sampling, which volcanologists have been doing almost daily through the OVG, too.

What no one knows is whether the magma underneath the lake floor is moving that lake floor upwards, which could conceivably set off a lake explosion:

  • You can’t put instruments down there without possibly destabilizing the gas field (I keep qualifying these statements because apparently no one knows what set off Lake Nyos in the Eighties, so who can really say whether Kivu is more or less stable because of its size? There are no real world data: just modeling and statistical analysis).
  • Someone pointed out this over at Talkweather. Magma bulges under lakes often displace water.

    Unfortunately, this is the rainy season, and per various local tweeters, all lakes in the rift valley are overflowing. It’s possible, though impossible to prove, that the lake floor is bulging, and possibly might reach a point where sediments would slide, stirring up the water and…boom.

    But you can’t infer that by using lake surface water levels just now.

Sigh.

Volcanologists have installed a camera up at the summit crater (French) — it’s not publicly accessible AFAIK — and I suspect they’re waiting to see if lava returns to form a new lake, as it always has done in the recent past, before taking the terrible but necessary chance of issuing an all clear.

Yes, there are cracks in the mountain now, and that could lead rather quickly to a repeat of the flank eruption, but it probably would mean that the crater collapse up there isn’t pressurizing the magma underneath Goma and the lake (as it did at Kilauea in 2018).

I haven’t been able to confirm whether this video is from 2021 or from 2002 (the last time the lava lake drained), as were some unattributed photos this account tweeted. The text is ambiguous and I suspect that it’s the lava lake coming back in 2002.

Those are probably the two best-case short-term scenarios: re-formation of a lava lake at the summit and/or the magma that is now under inhabited areas freezing in place without further eruption.


May 31, 2021, 4:20 p.m., Pacific: The volcanic crisis rages on:


Sound of crickets chirping. (Image: M. Asmani/MONUSCO)


News coverage of this eruption is sort of the opposite of what it was for Kilauea in 2018. Then, of course, everyone filmed those lava torrents, but there was an equally spectacular caldera collapse up at the summit that few people were aware of.

News camera work must show action, and Kilauea’s caldera collapsed slowly, for the most part.

At Nyiragongo, the caldera collapse produces ash plumes, which fits the volcano picture journalists focus on, so there’s recent footage of that.

But the big question is whether the magma that’s under the city of Goma and, especially, under Lake Kivu, is going to come up. That would trash eastern Goma (again: flows went through there in 2002) and, if an eruption happened on the lake bed, it could cause all that stored methane and carbon dioxide out of solution in a limnic eruption.

But you can’t film a lake 24/7 for possibly weeks on end. There’s no climax, either, no deadline crossed so everyone can cheer and shout “It didn’t happen! Yay!”

That is what we all hope will happen — especially the 400,000 Congolese evacuees — but it’s not an easy story for reporters to cover.

There is some good news, though:

2021-5-30: Current seismicity and ground deformation data continue to indicate the presence of magma under the urban area of Goma with an extension under Lake Kivu.

Seismicity and deformation continue. Although seismicity above baseline is still recorded, the energy dissipated by these earthquakes continues to decrease. The location of the earthquakes and the direction of the GPS displacements indicate a halt or pause in the propagation of the magmatic intrusion towards the south. A decrease in the displacement velocities measured by the GPS network seems to confirm these observations. However, the lack of resolution of the GPS
and seismological networks, linked to the presence of the lake, does not allow us to exclude a possible future migration of the intrusion towards the surface.

2021-05-29: Current seismicity and ground deformation data continue to indicate the presence of magma under the urban area of Goma with an extension under Lake Kivu. Seismicity and deformation continue. The number of earthquakes detected in 24 hours decreases slightly, as do the deformation rates. However, this decrease in the phenomenology at this stage cannot yet be interpreted as the end of activity. During phases of volcanic activity, periods of higher seismic activity often alternate with phases of lower seismicity. Seismicity above the baseline is always recorded. These observations are always consistent with the presence of magma at depth. Ash fallout may occur as a result of the collapse of parts within the crater. The stability data for Lake Kivu do not currently show any significant change (the latest available data is from 27 May 2021).

So, it’s still a waiting game.

There is a central information source now! It’s in French, but still very useful. (Check out the whole thread: they’re not just on Twitter.)


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May 29, 2021, 9:44 a.m., Pacific: The good news is that there’s no news to report. Yet. Let’s see how things go.


Update, May 28, 2021, 2:03 p.m., Pacific: I can’t find any new satellite image tweets or follow-up on the reported summit trip, other than that they wanted to know the status of the old lava lake. Perhaps we’ll hear more tomorrow.

Collapses like that can sometimes pressurize magma chambers.

Found this ArcGIS story-map of the eruption, though. It’s very technical, intended more to aid volcanologists and emergency managers, I suspect, than for public education — that will have to wait intil the crisis has ended.

Also, Reuters quotes an OVG official saying that they don’t think the likelihood of a second eruption is high. There is no mention of the summit field work in connection with this; the story was tweeted about two hours ago. Authorities are still discouraging people from returning to Goma, yet people are doing so.

In some areas, though, refugees are receiving aid, particularly women and children.

Per Georiska:

In the last 24 hours, seismicity, although less felt by the population, remains high, with hundreds of events per day still being detected by the OVG. In view of these results, we can expect the tremors to continue in the coming days. The location of these events seems to have stopped its progression towards the South but remains localized under Lake Kivu. Surface deformations are still recorded by the GPS network. These observations are consistent with the presence of magma at depth. Ash fallout may occur as a result of the collapse of parts of the crater. Data on the stability of Lake Kivu currently show no significant change.

1:09 p.m., Pacific: Countering rumor and fake news; also, volcanologists went up to the summit today. Per Twitter translation, “DRC UNPC Goma denies: No volcanologist was attacked or kidnapped by any negative force in the forest of the Nyiragongo volcano. The OVG did not lose surveillance equipment during the ongoing expedition to the summit of the volcano on Friday.”


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9:14 a.m., Pacific:

This particular update is also a post over at Talkweather.

Found out more in this article about what triggered the evacuation of part of Goma:

The evacuation order comes on the heels of a warning by the Goma Volcano Observatory (OVG), which monitors the pulse of Nyiragongo and the Nyamuragira volcano, 13 kilometres (nine miles) away.

In a technical note seen by AFP, the OVG said it saw worrying signs of activity by Nyiragongo that pointed to three potential outcomes.

In the first two scenarios, Nyiragongo would erupt again, sending renewed lava flows southwards towards Goma and Gisenyi, destroying buildings in their path before reaching Lake Kivu.

In both cases, the quantity of lava likely to enter the lake would not be enough to raise its deep-water temperature by at least one degrees Celsius (1.8 degrees Fahrenheit)—a key condition for a limnic eruption.

But in the worst-case scenario, lava flows from Nyiragongo would combine with volcanic activity under the floor of the lake.

This activity could take the form of a “fissural or phreato-magmatic eruption under the lake and/or a large earthquake of 6.5 or 7 magnitude,” the OVG said.

In this scenario, “a limnic eruption would take place and dissolved gas in the lake’s deep water would rise to the surface, especially CO2…

One of those Congolese volcanologists tweeted this (it’s the rainy season there, which doesn’t help evacuees at all):


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Perhaps this was taken from Mount Goma in town, at the Observatory. The plume might be degassing combined, perhaps, with ongoing collapse of the former lava lake’s conduit. Haven’t seen any recent tweets of satellite photos yet

A quick look at Twitter this morning shows a few responsible voices like these trying to be heard over a rising storm of people wanting to convince themselves that the worst is over. The volcano is quiet; the lava lake has drained (they probably aren’t likely to think right now of Kilauea’s 2018 eruption after two lakes drained); the conditions they face are terrible, both physically and socially (interruption of power and water supply; theft and violence on the road and in camps; lack of preparation to receive them: possible looting back in Goma; political corruption; diseases like cholera, etc.); and they are human beings who, like everyone else, long for their homes during a crisis.

Many families, reportedly, are going back. Graphs like the one below, which shows magma rising closer to the surface, don’t count for diddly with them. That’s understandable but going back to Goma just now is a really bad idea.

Incidentally, this graph does show a trend towards the surface again today. (I edited this statement from mistakenly saying the magma was going down, after rereading the graph: denial of bad news is a powerful instinct 🙁 The depth of seismic activity did drop yesterday, meaning that something from deeper levels — magma, presumably — is breaking rocks as it moves; now, it’s fracturing rocks closer to the surface; this is not good news.)


Rwanda Seismic Monitor


It’s a heckuva situation when a lava flow that might trash your town is the best-case scenario (#’s 1 or 2, in the OVG assessment, above). Unfortunately, there are three fresh cracks in the mountain, so a new lava lake seems unlikely, though that would be the best case.


Update, May 27, 2021, 8:10 p.m., Pacific: Per reliable sources, including Euro News (French), parts of Goma are being evacuated because of the high risk.

5:05 p.m., Pacific: VDAP (the USGS/USAID volcanic disaster program) just released this diagram of the eruption:



VDAP


They identify three vents along fissures in the mountain (red). The May 22nd flows are outlined in yellow, and airports are purple.

It looks to this layperson like vents 1 and 2 are the sources of lava that initially flowed towards Rwanda, which is nearby. Vent 3 is disturbingly close to town, but not near the lake.

Satellite images show collapse in the summit crater, now that the lava lake has partially drained (similiar to what happened at Kilauea in 2018 and here at Nyiragongo the last time this happened, in 2002):


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I was thinking that would explain the earthquakes that are ongoing in and around Goma, and it’s probably contributing, but there is still magma moving underground, per this source:

Current seismicity and ground deformation data continue to indicate the presence of magma under the Goma urban area with extension under Lake Kivu…Data on the stability of Lake Kivu currently show no significant change.

In summary, the crisis is not yet over.

Details? Okay, here is the latest GVP report:

At around 1815 on 22 May seismicity at Nyiragongo spiked, around the same time observers reported at least two fissures opening on the lower S flanks, NW of Kibati (8 km SSE) and Rukoko (10 km S). Lava from the first fissure, originating near the Shaheru crater, flowed E over a major road (N2) and then S. The second fissure produced lava flows that traveled S, overtaking and setting fire to many houses and structures in communities north of Goma, just W of Monigi (12 km S). Video posted on social media showed lava fountaining from the fissures, a glowing red sky, and residents running through the streets. About 1,000 homes and buildings were destroyed and about 25,000 people were displaced. The lava cut off electricity and water supplies to some areas. The flow may have been as wide as 1 km and stopped 1.25 km from the Goma International Airport, in the SE part of the city, during 22-23 May. According to the Toulouse VAAC ash plumes may have initially rose to 13.7 km (45,000 ft) a.s.l., though subsequent estimates put the ash plumes mostly at 6.1-9.1 km (20,000-30,000 ft) a.s.l. during 22-23 May. Satellite images and local scientists indicated that the summit lava lake had drained before the flank fissures had opened, but began refilling afterward; collapses in the summit crater were the likely cause of the ash plumes.

Initial reports indicated that about 32 people had died: about 12 from lava and gas asphyxiation while crossing lava flows, and most of the rest from accidents while fleeing. Several people, including many children, remained missing, though families were continuing to be reunited.

Seismic data during 22-24 May showed events seemingly propagating from the summit area to the S into Lake Kivu. Several strong earthquakes shook buildings in Goma, causing some to collapse and injure people; a news article noted that tremor was felt about every 30 minutes beginning around noon on 23 May. Both airports in Goma closed for security reasons. A M 5.1 earthquake with a hypocenter beneath Lake Kivu was recorded at 1037 on 24 May. The VAAC noted that ashfall around the volcano and in surrounding towns was visible in satellite data. Cracks a few 10s of centimeters wide opened in different parts of the city on 25 May. The cracks stretched for several hundred meters from the northern city limit down to the lake, and were nearly 100 m long near the airport. Some cracks were hot and emitting gasses, and some were flaming. Ash plumes rose to 6.1 km (20,000 ft) a.s.l. and drifted S; ground-based reports indicated ash in the atmosphere above Goma. Seismicity remained intense on 25 May with more than 130 earthquakes between M 2 and 5 recorded in a 24-hour period. News reports indicated hundreds of damaged buildings in neighboring Rwanda.


Original post and eruption live blog:

Technically, the lava lake (shown above at some earlier but recent date) drained out through at least one new crack in the volcano’s wall. Fortunately, it wasn’t as deep as it sometimes has been — you can see the “bathtub rings” from former high stands in the image above, too.

There is currently pause in, or perhaps an end to, this eruption phase, but we need to understand that the volcano has very little monitoring.

No one really knows what is going on underground right now.

This was just a superficial event — the containing walls cracked a little bit. If Nyiragongo 2021 follows the past, things now will quiet down for a while as the lava lake slowly refills.

If…


May 23, 2021, 7:03 a.m., Pacific: I have moved yesterday’s updates here from the original post.

Here’s the news I’ve found so far today:

  • The lava did stop in Buhene District, a few meters from Goma’s city line. Volcanologist Dario Tedesco at the Goma Observatory is quoted saying that only the lava in the crater emptied; more did not come up from below. (Reuters)
  • Another flow had headed for Rwanda, through unpopulated areas, and that stopped, too, per Reuters.
  • Per the Kinshasha Times (French) about four hours ago, the eruption began around 6:30 p.m., on May 22nd and ended around 4 a.m. on the 23rd. Several villages have been destroyed and five people are known dead from direct causes (French). Everybody is still waiting for an official word on the situation.
  • The status of Goma International Airport — vital for relief efforts — is unclear to me. Reuters reports it was untouched. However, the governor of North Kivu District, per Kinshasha Times (French), warns that the airport is “under threat of active crack in the basement” (via Google Translate).
  • About an hour ago, a tweet on the TROPOMI satellite sulfur-monitoring account reported that:

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    Nyamuragira is very close to Nyiragongo, but as far as I can tell, it isn’t erupting. Unless some other volcano in the area has gone off, which isn’t likely given absence of comment online, it is probably residual from yesterday’s eruption.

  • People who fled are returning to their homes, if they’ve still got one.

May 22, 2021, 3:23 p.m., Pacific: Just read that Nyiragongo is erupting and the DRC is attempting to evacuate East Goma.

See original post on this Decade Volcano below. I’ll try to gather more information and do a more detailed update soon.

This, among other tweets, from the a high-ranking official at the Goma Volcano Observatory:


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That contradicts some reports I’m seeing that say the lava is flowing towards Rwanda. The AP BBC report at that link above states that lava has reached the airport and also cut a highway; power is out in much of Goma. And an Observatory employee is quoted saying that it seems lava is heading for the city center.

Edit: Reuters cleared that up:

Dario Tedesco, a volcanologist based in Goma, said new fractures were opening in Nyiragongo, allowing the lava to flow southward toward Goma after initially flowing east toward Rwanda.

“Now Goma is the target,” Tedesco told Reuters. “It’s similar to 2002. I think that the lava is going towards the city centre.”

“It might stop before or go on. It’s difficult to forecast,” he said.



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4 p.m., Pacific: This is a developing situation, with some fake news already circulating (videos of the eruption in Iceland being passed off as Nyiragongo’s) and lots of confusion on Twitter. Will therefore hold off on doing a full update for a while and just pass along various reliable tidbits that come along.

This eruption is already devastating to the region, but what we really don’t want to see is:

  • Lava reaching Lake Kivu.
  • Fissures opening up in Goma or, worse, under Lake Kivu.

Either event could cause the lake to overturn in a carbon dioxide/methane eruption (see original post below and the references quoted in it for reasons why).

4:42 p.m., Pacific: Tweeted about forty minutes ago:


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Can’t find Buhene-Kihisi on a map, but it looks like a Goma suburb here.


5:05 p.m., Pacific: Buhene, “north of Goma”:


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Per the Kinshasha Times, via browser translator:

…the lava has already reached the town of Kihisi on the border with the Bujovi district in the city of Goma. It also indicates that these lavas are a few meters from the Maman Olive station, which makes the situation very worrying…

To the Rwandan authorities to reassure that “the national emergency plan is in place to ensure security and humanitarian services”, it is appropriate to note that more than 3,500 Congolese have taken refuge in Rwanda.

I don’t know what the Maman Olive Station is, but if relevant, lava did reach a gasoline depot in East Goma back in 2002 and there was an explosion.

5:27 p.m., Pacific, Pacific: Per this Kinshasha Times (KT) story and others on the site, the eruption began around 7 p.m. local time: 6-1/2 hours ago. Gas stations have been urged to empty their tanks — into what, I have no idea. Also, at least one village has been inundated and roads have been cut.

This KT story, posted four hours ago, describes and shows video of panicking people, but other photographs I’ve seen show calmer, more orderly evacuations.

Here is an overflight the UN troops did, posted about three hours ago at a time when it didn’t appear Goma was in danger. From the sheer volume of lava — and at Nyiragongo this flows very quickly, too — I’m thinking it possible that the lava lake is draining.


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6:58 p.m., Pacific: Here is Reuters reporting that two authorites say:

Emmanuel De Merode, head of Virunga National Park, asked park employees in parts of Goma to evacuate, according a note seen by Reuters. He said lava had reached the international airport on the eastern edge of the city but that it was not likely to reach other parts of Goma.

Celestin Kasereka, head of scientific research at the Goma Volcano Observatory (OVG), told reporters he did not think the lava was flowing fast enough to reach Goma.

Also, I’ve seen a single report that the lava stopped at Buhene, but that is not yet confirmed.

This video might be from the Buhene-Kihisi area. It shows a cooler, thicker lava — more of an a’a texture — not the runny pahoehoe-style lava that, from general reports, flowed first from the fissure (and which poured through Goma in 2002).

Fortunately, the crater lava lake wasn’t as deep as in 2002 and perhaps that has limited things.

It’s not very helpful to these householders, but perhaps the flow is coming to a halt here. No confirmation yet, but I’ll do a post on Sunday about this.

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Featured image: wayak/Shutterstock



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