A river of molten rock continues to pour from a volcano, known as Mount Nyiragongo, in the Democratic Republic of Congo. The volcano began erupting Thursday, killing dozens, swallowing buildings and forcing hundreds of thousands to flee the town of Goma. VOA News Now's Steve Norman spoke with geo-hazard specialist John Lockwood. He has been to Goma and knows the history of Mount Nyiragongo.... in fact, he was there after the volcano's last eruption in 1994.
Lockwood: "Nyiragongo is an amazing volcano. It would be high on the list of world tourist spots if it weren't so remote. But it's an absolutely perfect cone that looks decapitated, flat-topped, from afar. But when you get up to the rim - and it's a very difficult climb to get up there; it's nearly 10,000 feet (3,000 meters) high, I believe - when you're up there, it turns out that rim is actually a knife-edged rim, encircling a very, very deep, very wide crater."
Norman: "Let's talk a bit about Nyiragongo. It has erupted several times before; you've been there. Would there have been any indications to the people of Goma that it was going to erupt this time?"
Lockwood: "This time was a bit different than others. The 1977 eruption, which was the most disastrous in history, the first historical eruption out of the flank of the volcano, it killed about 500 people. That had been preceded by years of activity in the summit crater, the buildup of a large lava lake in the crater. This time, apparently there was no extensive lava lake in the crater. It was simply an eruption that broke out on the flanks with little warning."
Norman: "And we understand that in each of these cases the lava moves very fast down the mountain; and that's what traps the people, does it not?"
Lockwood: "Yes. The type of lava erupted by this volcano, and many volcanoes in the East Rift zone of Africa, these lavas are extremely fluid. They contain a lot of the element potassium. They are called alkalic lavas, and they're noted for their incredible flow velocity because their viscosity is extremely low. You have the impression that it's like running water relative to other types of lava."
Norman: "And it's quite hot?"
Lockwood: "Yes. The melting temperature of those lavas are something in excess of 2,000 degrees Fahrenheit (1,100 Celsius)."
Norman: "Is the earth affected, or at least vulnerable, to other things like this? Are there lots of eruptions of volcanoes? Is there any indication now, with Nyiragongo going, that others might erupt?"
Lockwood: "Not related to that, but yes, the fact is that there are lots of volcanoes on earth. Not many get publicity, but there are about 500 volcanoes we consider active. And they have been erupting for millions of years, since the earth was born. What is making things different now are two things. First, the increase in the world's population. Many people are living much closer to dangerous volcanoes, in places they wouldn't have lived before. The other thing, of course, is the revolution in communication. This volcano could have erupted 100 years ago and no one would have known about it for many weeks or months. But now, with communication, any time a volcano erupts and threatens a population, people know about it all over the world quickly."
Norman: "And Nyiragongo, will it erupt again soon?"
Lockwood: "To answer your question about soon, we don't know. We don't know what's going on. We don't know. The last word I had is that the eruption is continuing. Lava continues to flow from the vents. This was the information a couple of hours ago. The 1977 eruption was quite brief; it was something like an hour's duration. This one has lasted, I believe now, over 24 hours. But as far as the future, the problem is Nyiragongo is not very well monitored. There is some rather primitive seismic monitoring equipment that measures small earthquakes, but not nearly enough to do a very good job of predicting the future."
John Lockwood is president of the company Geo Hazard Consultants International, based in Hilo, Hawaii. He spoke with VOA News Now's Steve Norman.