Mount Nyiragongo is likely to continue to erupt over the years to come and what can be done is for those living in the region to adapt ways of living with an active volcano, according to Dr Ivan Twagirishema, the COO of Rwanda Mining Board. He spoke with The New Times’ Emmanuel Ntirenganya on the aftermath of the eruption that took place a few days back and what can be done to minimize the damage from possible eruptions in the future. Excerpts: The eruption of Nyiragongo was somehow unexpected, what is the reason for that? The volcano’s previous eruption was in 2002. When a volcano erupts, often the magma inside it is emptied [as it is ejected as lava on Earth’s surface]. Researchers who monitor the volcano had forecast that it could erupt in four years. This was in 2020. They had based their prediction on the magma refilling. And, when it is full of magma, it is like a bucket full of water. Such abruptness is justified by the fact that when its inside is full of magma, and the factor that can cause it to be ejected comes from the core of the earth, just a simple factor can cause a shock inside which makes it to erupt from any opening. Often, a volcanic eruption is preceded by tremors, which occur when there are obstacles that were preventing the magma from being ejected from the inner part of the earth. That is why they had estimated four years, and people though there was time to get prepared [to deal with it], but its eruption was unexpected as it occurred just after one year [since the prediction was made]. There are tremors that occurred after Nyiragongo erupted, what caused them? Let us compare the volcano to a balloon. If you fill a balloon with air, in the case of Nyiragongo, it took about 19 years for it to be filled until 2021 [here, magma is compared to air]. If you stick objects onto that balloon through use of adhesive tape, then, pierce it in a second [to deflate it], you realise that the process that took 19 years for it to be filled, is entirely emptied in just a short time. What will happen to the objects stuck on the balloon? Some will be destroyed, others will fall. That’s when earthquakes occur. Tremors occur when the volcano interior that was full is emptied and as it contracts, it somehow pulls the nearby objects. Houses and roads among other properties on earth are like the objects stuck on the balloon I referred to, so they are shaken in case of eruption. That is why there have been cracks in some areas. How deep are the cracks that were made as a result of the tremors? They vary in size. There are some which are new, but many of them were created in 2002 [during past eruption.] Indeed, the area has been weakened by the previous eruption. But, after the eruption is over – in this case over 19 years had elapsed, the cracks are filled by such as by soil and debris brought by erosion. In about one year, some of the cracks will be covered. But, it is the upper part that is covered by the soil or debris. That does not reach the entire part of the cracks which have some 100 metres of depth, which is why there are areas where some parts are sunken as the cracks have already been existing. But, it does not mean that lava will be released from such cracks. Magma is found hundreds of kilometers from the inside of the earth, while the earth’s crush – the outer layer of the earth – on which we live is just about 30 kilometers [and can reach 70 kilometres in places with high mountains], which is thin. The cracks that were made are about 100 metres. Some people say that it is very deep, but even the 30 kilometre deep crust is thin compared to the earth’s thickness. Does this mean that people living around the volcano are in imminent danger? There is no certainty that the volcano cannot take less time to erupt than it has been taking up to know. What is most important is to further its’ monitoring so that people know that when the magma is at about 300 metres or 400 metres before filling its inside. Since the areas that are affected by the cracks are known such as Goma in DRC and Rubavu in Rwanda, one of the solutions is that there should be a strategy to factor that in the masterplan so that it is indicated where it is appropriate for settlement, and where it is not so that, going forward, people are taught how to live with the an active volcano. Nyiragongo is our neighbour and it is there to stay. We cannot relocated it. So, we should learn how to live with it, and know its history so that its eruptive activities do not catch us off guard. Based on the past activity of the volcano, it can erupt again, because it has erupted over 30 times so far. But, it is difficult that such could happen, say, in one day because magma has to fill its interior. But, when it is going to eject lava, there are signs that can herald. As we speak, there are photos taken by satellite and drones from above the Volcano which show that it is empty [no magma is left]. We realised that it has been taking between 15 and 19 years to be filled. People in Japan, which is prone to earthquakes, used to build light buildings such as in form of tents which and once they collapsed, they could not kill the people inside. But, currently, their buildings such as multi-storied ones have foundation with a huge spring installed into the ground such that when earthquake hits a structure with say 10 or 20 floors, it just swings and gets well positioned back. Their technology was dictated by the circumstances in which they live. How dangerous are the gases emitted by the volcano? The gas from a volcano is not just emitted when it has erupted. Nyiragongo is known all over the world because of the gasses it emits. Among the gasses that are emitted from the volcano include carbon dioxide and hydrogen sulfide which is even more dangerous than carbon dioxide. The hydrogen sulfide that Nyiragongo emits into the atmosphere per year is equivalent to that released by all the factories of Europe in the same period. The volcano is not closed, it releases such gases continuously. They do not stop in Goma and Rubavu, they whirl around our atmosphere. They might be emitted in large quantities in case of eruption, tough. There has been worry that lava from Nyiragongo could get in contact with the inflammable methane gas beneath Lake Kivu, which can cause a catastrophe; what is the possibility of that happening? Between 0 and 90 metres of depth from Lake Kivu’s surface is an area suitable for aquatic life; that is where fish live. Then, you enter another part where other small aquatic creatures can live. The gas is found from 190 metres from the surface. A catastrophe can only occur if the volcano erupts a lot of lava, which then goes past Goma and Rubavu towns, then reach the lake’s depth where the gas is located. This year, the lava stopped at one kilometer from Goma International Airport. But, in 2002, the lava destroyed part of Goma, and reached Kivu, penetrating up to 100 metres of its depth. This implies that it could not get in contact with the gas, though. There is limited risk but based on the past experience, that would involve many instances and people can take different measures [in response to that in the process]. What is the capacity to monitor Nyiragongo? There are sensors that were installed on the volcano so that they show its state inside. Technology has advanced. People could be in the US and they get satellite data then they sent us the information even after interpreting the data. The volcano is in DR Congo … that is why Goma Volcano Observatory (GVO) is there. This station is in charge of monitoring Nyiragongo and the impact of its eruptive activities in the region. In Rwanda, we have different sites which enable us to monitor earthquakes – seismology. However, we will look at ways to enhance cooperation with the centre in Goma, but also increase our own monitoring capacity in the country. In addition, there are varied partnerships with other researchers across the world because the Volcano is monitored worldwide.
