Day 7 - Feeling hot, hot, hot...a natural steam room

Our friends here at Maili Saba Camp treated us to a lovely, traditional breakfast with arrow-root, sweet potato, and semolina waffles. It was really nice to sample their food, though it was incredibly filling! We had another day of sampling today, our first site to sample was near well 10 – where they have been venting the well to get rid of sulphur the entire time we have been here. Today the venting was much more vigorous than we have seen it before, and was producing a deafening roar.

One of the GDC scientists collecting a gas sample from the venting well 10. Notice the ear protection... today it was very noisy!

Just as we were about to head over to the lava a team of GDC scientists turned up and began sampling the gas and water coming from the well. Just about managing to hear over the deafening roar of the venting, Helen had a good chat with one of the scientists and was given a good deal of information about the general temperatures and pH of the gas/water sampled in the area. And also the type of connections they use for attaching a regulator and extracting the gas/ water. Helen had hoped to be able to do some water and gas sampling out here on this trip, but wasn’t able to get this information meaning we didn’t know what equipment to bring. Having met the guys sampling today, and them kindly sharing this information, Helen will be able to bring gas and water sampling equipment out next year. Studying the isotopic composition of the gas/ water sampled will enable Helen to determine the depth from which the gas has travelled up from, and the type of water – did it fall as rain and collect in the ground (meteoric)? Or is it water that has been trapped deep in the crust from the formation of the Earth or ancient tectonic processes (historic)?

As we were gathering our kit together to go and sample the lava I noticed that there was either steam or smoke rising from behind a large block of the lava. We went over to investigate and as we got closer it became apparent that the entire area was a ‘smoking field’ of fumaroles and surface emanations.

It was very difficult to get a picture of the steaming ground...you can see it ok in this picture. But every rock outcrop you can see was hot and steaming to some degree.

Everywhere there were rocks (the rocks where spatter deposits dotted among the grassy ground) steam was rising. In some places there were only small, occasional whisps of steam. In a lot of places though, there was a large amount of steam constantly rising. I could feel through my boots just how warm the ground was. Again, despite understanding how and why this was occurring, it felt quite surreal to actually be there experiencing this magmatic heat. All three of us – our driver Vincent came out with us too – were so excited by it we turned into big kids; seeing who could keep their hand in one of the hot steaming holes the longest.

Although the steam wasn't captured in this picture I think you can tell by my facial expression that my competitiveness led to me leaving my hand in a little too long!

On finding a large fumarole within a narrow gulley in the rocks we even climbed in , after testing how hot it was first of course! It was like a being in a steam room, just with a rather metallic smell as opposed to the smell of eucalyptus that is often scenting a steam room back home!

Entering the natural steam room...

We plan to come back here at dawn one morning next week and cook our breakfast eggs on the fumaroles :)

These smoking rocks were the edge of the lava we were planning on sampling, but with the surface heat and large volumes of hot water moving through them they were far too altered to collect samples. We travelled further along the lava flow until we found a good section to sample. As we climbed up and studied the lava flow it instantly became apparent that this had been a fissure eruption. A fissure is a long, linear eruption in the ground. They tend to exploit existing weaknesses in the rock, such as a fault or fracture.

A picture of a typical fissure eruption. Mauna Loa, Hawaii - Photo from USGS

The fissure eruption lava’s were sat on top of an old ropey lava flow upon which there were vast spatter deposits. Due to it occurring at the base of our last sample location (which was about 2km to the NW) we know the older ropey (Pahoehoe) lava was a very extensive flow. The extent can also be seen on the Landsat image.

We now have all the samples we have planned to collect, that’s not to say we won’t see anything interesting that we decide to sample. Tomorrow we will be doing some mapping.