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Volcanologist Jim Kauahikaua
(Interviewer- Wesley Okazaki)
(Wesley): What causes a volcano to erupt? (Jim Kauahikaua): We think a volcano erupts when there's too much lava underneath the ground until it's over pressured and we think that is because just before the eruption, this area will inflate just like a balloon so that suggests that there's lava coming up into it and causing the whole surface of the ground to inflate. So we think that's why but we're not sure. (Wesley): What causes earthquakes to happen in Hawaii? (Jim Kauahikaua): There are couple of different ways that earthquakes happen, probably the most common way here -- first of all, we have more earthquakes here than in southern California. We have a lot of earthquakes. So the most common kind of earthquake here on Kilauea has to do with magma moving through through the ground. And so that the constant pressure causes a lot of small earthquakes but we do get a lot of very large earthquakes like magnitude 6, 7 and 8's and those are the island itself slipping out over the island floor. The volcano is sitting on top of the ocean floor but that's actually a detached surface so the magma will push part of the island out and then the huge plane its slipping on will cause a large earthquake. (Wesley): How many volcanoes are there on Hawaii? (Jim Kauahikaua): If you count only the ones above sea level, there are five. There's Kohala, Mauna Kea, Hualalai, Mauna Loa, and Kilauea and there's two below the water. There's Lo'ihi off here about 25 miles, and there's another one off Kona side, the Mahukona volcano which is extinct. (Wesley): What are the positive sides of volcanoes and earthquakes? (Jim Kauahikaua): The good stuff about volcanoes is that they're really fun to watch and it brings a lot of interesting people to the island, like you guys. It's actually pretty exciting from a scientific point of view -- a lot of good stuff to work on and study. Earthquakes, I don't know if there's any good side. It certainly changes the topography of the island, so I guess you can say that's good, unless you like really liked it the way it was before. But all these little cliffs out here because of earthquakes and pieces of the island subsiding and collapsing -- can't think of too much else good about earthquakes, though. (Wesley): Is Kilauea dangerous at all? (Jim Kauahikaua): Kilauea is dangerous and if you just look out here we can see that even though this is a volcano, there's no lava flows exposed here. It's all kind of a gravelly thing because Kilauea erupts explosively, just like Mt.. St. Helens, even though we don't think of that way because it erupts so much more often as just lava flows. But these gravelly deposits just outside the observatory, and actually the observatory is built on them, are from an eruption that happened about 1790 or so, a little over 200 years ago It turns out that Kilauea erupts like this, as often as Mt.. St. Helens does, once or twice every two thousand years. So most of the time Kilauea isn't dangerous but sometimes it can be. (Wesley): Can a volcanologist predict how many times a year a volcano will erupt? (Jim Kauahikaua): In a way, yes. We map and date, for example, we take all of the lava flows on Kilauea and we map out how many there are and then we date all of them. So we know, for example, that 90% of the surface of Kilauea is less than a thousand years old. And say we also know that's the result of over 300 individual eruptions in a thousand years. So if we know that there are 300 individual eruptions in a thousand years, we can say that Kilauea erupts roughly once every 3 years. So in that sense, yes, we can. But that doesn't mean that you can say every three years Kilauea is going to erupt. It just means that's the average frequency of eruptions. If you're also asking about if we can predict eruptions, like if they're just about to occur, we have have actually a much better success rate in that because of these things I was saying about the volcano plate, there's a certain kind of earthquakes that happen, so when we see an increase in the number of earthquakes we know that an eruption is probably going to happen pretty soon. If we follow where the earthquakes are going we can kind of tell where it's going to happen. So kind of different in two senses, but, yes I know. Wesley): Does weather affect volcanoes? (Jim Kauahikaua): A good question on a rainy day. It's not clear that weather affects Kilauea or Mauna Loa but in some parts of the world, for the more explosive volcanoes, there is a connection between rainfall and the explosive type of eruptions. It seems that the increased amount of water in the ground can kind of enhance the explosivity of an eruption. Wesley): What's dangerous about a volcano? (Jim Kauahikaua): What's dangerous about Kilauea eruptions I guess is , probably the most dangerous areas are right at the vents where lava is coming out of the ground initially and at the ocean were lava is going right into the ocean. The reason is that those are two sites where local explosions can happen, for example, where lava is going into the ocean, lava will build out a bench from the old coast line. So it builds out this thing, but the whole bench is only built on sand and so we've measured that it'll subside at the rate of maybe a millimeter or two a day. It's real fast, relatively fast. And that means it would seem as if the bench collapses, the whole thing will just go off into the ocean and so we try to warn people not to go out on the bench there but a lot are hard-head and want to go see the lava. That's is probably the most dangerous thing at this point. The vent area right now is off limits because it's so dangerous and its danger is it's continuing collapsing. It's trying to make a hole like is right behind us here but it's doing it slowly so you don't know exactly when it's going to do the next little bit of collapse, so it's just safe to just stay off it. (Wesley): How do you prepare for a volcanic eruption, if it's going to go through a town or something like that? (Jim Kauahikaua): Well, first of all, an eruption is when the whole thing - when it comes out of the ground and the lava flows. It's going all over the place so during one eruption there maybe long periods where nothing is really threatening any town, threatening any town but if a lava flow looks like it's going to go into a town, then what we do is call Harry Kim on the Big Island because he's the civil defense director and Harry's the one who will come out to set up road blocks and try to evacuate people and so what we do for him is advise him about the specific lava flow hazards. We will keep an eye on the lava flow and we'll map it out every few hours to see how fast it's going to try to predict where it's going to go in the next 12 to 24 hours so that if there's somebody in particular danger in that area they can be moved much more rapidly than everybody else. We also keep track of where the lava flows are going because they often will in turn they're always burning houses and things but they can also sever power lines and water mains and that sort t of thing so civil defense defense people need to know exactly where the lava flows are going at any one time to warn people, customers downstream of the power lines or water mains, that kind of thing. So we have to make sure all of our gears are working right make sure we've got lunch packed and the right kind of clothes and we go. (Wesley): How hot can a volcano get? (Jim Kauahikaua): By that I think you're asking how hot is lava? Cool lava when it comes out of the ground is rarely hotter than about 1160 or 1170 degrees centigrade, which is about a little over 2100 degrees Fahrenheit. But it cools off pretty rapidly so a lava flow, for example, when it comes out you can watch it come out and in 10 - 15 minutes, if you have the right kind of shoes, you can walk on it and it will support a human's weight. It's really hot but you can do it. (Wesley): We were looking at the caldera over there. What's the green steam stuff? (Jim Kauahikaua): There's what's called a fumerole, which just means a place where gas is coming out. On the other side is the hottest gas vent on the surface of Kilauea, over 600 degrees centigrade.The greenish things that you see is actually native sulfur crystals. A whole set of crystals around it which kind of makes the fumes look greenish when it comes out. But there is a slight, very small amount of copper and the way the sulfur crystallizes so the sulfur itself gets a little bit bluish, which then makes the steam look bluish or greenish, or whatever you see. (Wesley): What do you think about geothermal energy? (Jim Kauahikaua): That's a loaded question. Where are you guys from, unh? Geothermal energy, is in theory, is a pretty clean source of energy. We have a geothermal plant on this island, a commercial one, that's been going for I think six years now, producing 30 megawatts of power pretty regularly. The only problem with it is that on Kilauea it is an active volcano. So any place that they're going to develop geothermal energy, it is going to be is a high-hazard, lava flow area, and it's certainly true of the area that they chosen to develop on this volcano. On one end of, yes, it is a cheaper source of energy, and it seems to be pretty reliable over the short term, at least 5, 10, or 15 years. But because it's in a high hazard area, you can't think about it, like a hospital, it's not going to be there in certainly 50 years, for example. It's just in a too high hazard area. For example, that when they drilled the wells they located them very precisely, in the event of a lava flow they could chip down through the lava and find the wells again. Their whole plant is removable, supposedly in 24 hours. I'd like to see that, that's what they say. So there's good and bad things about geothermal energy. |
This Email interview with Brad Lewis, (http://Lavart.com) well-known volcano photographer provides us with insight of the beauty and excitement of sharing images of volcanoes with the world. |
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