This summer a team from University College London undertook a scientific adventure to collect lava and gas samples from an active volcano in Tanzania. Faced with a limited budget and the task of rigging 300 metre lines over the crater, they approached DMM to support the expedition. PhD student, Kate Laxton, sent us this short report.
Expedition to Ol Doinyo Lengai Volcano, Tanzania 2019
Ol Doinyo Lengai is revered as the ‘Mountain of God’ by the Maasai people who live below its slopes within the East African Rift System. It is also happens to be the world’s weirdest volcano: famous for burping out unique natrocarbonatite (sodium carbonate) lava flows, complementing the local zebra by mimicking their black and white stripes.
Over the span of 100 years, which incidentally is as far back as our observations go, it wouldn’t be unusual to see the Earth’s coldest lavas (< 600 °C) spew out over the crater floor, often for decades at a time. Then out of the blue, you could be a witness to violent explosive eruptions, throwing up chunks of siliceous lava and country rock.
It is because of the Rift that the volcano exists in the first place, although why natrocarbonatite behaviour occurs only at this spot is still under debate. For this reason, the volcano attracts scientists and visitors alike, not least because of the challenge of scrambling up its steep scree slope in the dark, avoiding the deeply cut ravines either side of trail. My challenge as a PhD student was how can I help to monitor this volcano without money, equipment or repeating the same experiments as everyone else.
As a rock climber, I tend towards a more mechanical approach to my fieldwork. Mostly because technology is notorious for its smooth function right up until that crucial moment when it all fails catastrophically. I also knew before the expedition that I needed the simplest, most flexible and efficient rig system possible because we were about to try wrangling the summit of an active volcano. The summit has a gaping hole in it courtesy of the last explosive eruption of 2007-2008.
So, instead of waiting decades for the crater to hopefully fill up again, we decided to stretch 300 metre ropes across the open mouth of an active volcano. Using a system of pulleys we lowered the equipment to collect lava samples and gas measurements from the crater floor 100 metres below. All from the relative safety of the crater rim. Given the budget, I could hardly expect to swoop in by helicopter à la Lara Croft.
It literally took months of careful planning, budgeting, recruiting and mulling over any potential pitfalls to pull this off. Thankfully, no one fell in the pit, and although hard won, it worked.
We had around 40kgs each of equipment, food and water to lug up to the summit; involving nine people making two trips to set up camp for the five of us staying at the top. We lasted a grand total of eight days and nine nights before descending, a day or two sooner than expected. The heavy winds had beaten us down and seemed determined to knock us off the top.
The rig itself was absolutely solid. The main rope had been trailed around the crater rim, catching on various boulders but eventually anchored-in on day one. It helps when the weight of the rope isn’t trying to drag you into the crater. So, by comparison, installation of the finer accessory lines was remarkably effortless. With all that in place, we were left to play with our multiple Triple Attachment Pulley set-up to our hearts’ content. The set-up we used is fairly obvious from the photos—involving lowering gas sensors and sample buckets from the fixed line into the crater.
Ultimately, mechanical advantage won out. As expected, our radio comms and electronics failed us at times, but our ropes, pulleys and forearm strength held true. It wasn’t the place for equipment failure. In the end we managed to collect the first lava samples and gas measurements from the crater floor of Ol Doinyo Lengai since the last explosive eruption in September 2007. Scientifically, that was an achievement. Logistically, it was an epic adventure.
Kate Laxton–London NERC DTP Student–funded by the Deep Carbon Observatory with the support of the University of Dar Es Salaam and the Geological Survey of Tanzania.
With: Emma Liu, Arno Van Zyl (Vertica Ltd), Papakinye Lemolo, Amedeus Mtui, Ignas Mtui, Boni Kicha, Boni Mawe and Baraka.