The night after I helped set up the time-lapse camera to record any collapses of the vent rim, there were two magmatic explosive events. The rim area beneath and to the east of the plume is littered with spatter material. The explosions happened about an hour after I visited the visitor overlook. If only I’d been an hour later! At any rate, I was able to go down into the caldera again yesterday to assist with sampling gases from fumaroles. These are holes in the ground near volcanoes that emit gases and steam. We decided to see the spatter material before venturing in on foot.
Let’s just say it’s a good thing that this road is closed to the public. Some of the ejected material was incandescent at the time of eruption, which signifies fairly high temperatures.
We left that area and journeyed to the less-travelled southern end of Halema`uma`u crater. Here’s a view of the crater wall that you can’t see from the Observatory or Jaggar Museum.
We continued hiking around to the western edge of the crater and stopped for a bit to watch the plume. The vent was making banging noises like it had all day on Tuesday, and after a while it switched to gas rushing sounds. It’s akin to the noise a 747 jet makes as it lands. At one point the plume almost died out, and then it resumed more vigorous puffing and turned brown.
Our resident gas geochemist was nice enough to model for me.
He’s standing in an area of the crater known as the Postal Rift. When Halema`uma`u was filled entirely with lava back in 1919, visitors could walk right up to the rift and dip their postcards into the lava. The edges would become a nicely singed, unique souvenir of their visit to Kilauea. Try to imagine that whole crater and the rift where the scientist is standing as a lava lake. Pretty amazing.
So, I’m sure you’re all curious about what sulfur dioxide does to the areas surrounding it.
It makes sulfur crystals! When sulfur-rich gas seeps out of the earth and the area remains relatively undisturbed, it gives sulfur crystals the chance to grow. They’re beautiful.
Here’s a fumarole up close and personal. The crystals are about 1/2-3/4 inch at their longest. They also smell like rotten eggs. Hey, perfection is hard!
This is what we do with fumaroles…we sample the gas they emit! I’m using a technique called evacuated-bottle fumarole gas sampling. First we measure the temperature of the fumarole using a probe. The temperature around the crater is right near the boiling temperature at this altitude = 94.8 degrees Celsius. After that we insert a teflon tube into the fumarole, and connect the tube to a specially-made vacuum-sealed Pyrex bottle. We then pump the gas into the bottle slowly, and make sure that it cools and condenses enough to close the bottle off.
Once we get back to the lab we run the samples through a manometer (pressure-reading device) to compare the gas pressure in the bottles to the ambient room pressure. After that we stick it on a gas chromatograph and measure the bottle’s levels of air, water, CO2, and SO2. Fumaroles from different areas have different gas concentrations, and this helps us to understand the magma and gas beneath the crater’s surface.
Not a day goes by without me learning something incredibly interesting!