Flew out to the new fissures today accompanied by Tim Orr of USGS (flown by David Okita of Volcano Helicopters, of course – he set up some great aerial shots for me today – click on photo to see video clips). We got put down right below the fissures and upwind of the huge channels barreling down the slopes of Pu`u `O`o, and spent a few hours following the flows. Even though it has been days since the fissure broke open, there were still good-sized open channels. We had to climb up on some pretty hot flows to get a good view. I was a little worried about the boot soles, but they held up fine. We did have some cooler ground to retreat to. The terrain up here is all shelly pahoehoe – hollow rolls of lava that form near vents. The rock is generally one or two inches thick – and thus collapses easily under your weight – but the hollow spaces you fall into can be a lot deeper than that. Bad enough if it’s cold, but a real bummer when it’s hot. I made it without any shin injuries and only got a little stuck once. Walking in the folds helps because it is a little thicker there, though you end up having to contort your ankles a bit.
Up near the fissure, where the cone is steeper, the lava in the channel was moving fast – it was very impressive. Closeup shots were hard to get through the intense heat waves, though. The sound was also very difficult to capture through the wind and buzzing helicopters. The fissure would make the occasional jetting and hissing noises, while the sound of the channel itself is more of a rustling, whispering sound, interspersed with thumps and clinks and rattles as solid bits of crust scrape against the sides.
I was reminded as we picked our way along the channel that this job is much easier with two people. Fortunately Tim offered to carry the tripod, which helped a lot. You really want a hand free when walking on shelly pahoehoe. The problem with working on hot ground is that you can’t set anything down, so setting up a tripod and camera, getting a drink of water, taking gloves on and off, changing batteries… it all requires a lot of maneuvering. You can’t set the backpack down or the nylon might begin to melt. We were wearing flight suits and heavy boots, of course, so the heat was manageable, except when we got really close to the channel – there the radiant heat was intense. Fortunately David let us leave our helmets and my shooting rig in the chopper.
The last place we made it to was the most spectacular – a huge lava falls with a pond at the base. We were able to get right up to it and look down into the incised channel. The lava at the base of the falls was splashing up like a small dome fountain and occasionally spattering lava on the walls. The amount of lava seemed to wax and wane a bit. We’d noticed along the channel above how the crust would build along the sides and then break away as the lava level rose. Not sure how much is local effects (constriction of the channel forcing the level to rise) or an actual change in effusion rate of the lava. But by the time the lava reached the falls it would increase and decrease noticeably. And wow, the falls were impressive. Altogether a great filming day.