September 11, 2016 • Leave a Comment
The current eruption of Kilauea, in the Island of Hawaii, has been going on continuously since 1983. We visited Hawaii for the first time in 2003, and have been back about every other year since then. And yet, for one reason or other, we had never been able to see Kilauea's eruption up close. Since both of us are geologists, this was beginning to be embarrassing. This summer (2016) we were there at the right time, when flow 61g was picking up steam, and managed to get close to the active lava flow. The first thing that struck me was how unbearably hot it is next to the lava flow. I should have expected this, I am a geologist and, perhaps more to the point, I take pride in considering myself something of a physicist who deals with rocks. A body at 1200°C radiates in the visible part of the spectrum (that is why it looks red) and also puts out a lot of energy in the infrared part of the electromagnetic spectrum. So, heat transfer from the lava flow to the observer, and said observer's camera gear, is radiative heat transfer. The insulating properties of air don't matter. Obvious, and I of course knew it, but as I was hiking towards the lava flow this was far from my mind. When I stepped over the last hard lava hummock and I was face to face with the flow, only a few meters away, the heat, and the reason for the heat, suddenly hit me. I also take pride in being a theoretician more than anything else, I love equations, but sometimes forget what those equations mean in the real world. Rough awakening.
The images in this website are only a small fraction of the several hundred images that I captured over a couple of afternoons and evenings next to the lava flow. They were all shot with the same equipment: a manual focus 35-135mm Zeiss zoom and an Olympus EM-1 digital body, plus a tripod when it got too dark. I was concerned that the beautiful glass in my Zeiss lens would devitrify at that temperature, but it survived. Come to think of it, the organic matter that the photographer is made up of would have broken up before the glass. I was also concerned that the camera electronics would be fried, but they also survived. I survived, but became very thirsty, which made the hike back to the car something of a drag. My technique to shoot the pictures was to spend perhaps a minute or two shooting next to the lava, sometimes as close as 1 meter from the lava front, and then walk behind some little knoll that cut the IR from the flow, to cool off, and let my gear cool off, for a few minutes.
The flow is a classic pahoehoe flow. Much of the activity goes on inside the hardened crust, with the lava flowing along lava tubes. Where the tubes breach the surface of the flow there are lava breakouts that can be quite spectacular. In some case motion is slow enough that the crumpling of the viscous lava is frozen even at relatively low shutter speeds. In other cases the lava moves fast enough to blur the image. The lava viscosity increases exponentially as it cools down, which explains structures like this or this. In other cases enough lava surges forward that it stays hot long enough to yield a fairly smooth liquid surface. I'm not fond of any language or metaphor that has supernatural connotations, but I must say that some of the images do look like the Gates of Hell.
No comments posted.
Photos, commentary and opinions by Alberto Patiño Douce