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Seismology

The Journey of an Antarctic Seismologist

The Journey of an Antarctic Seismologist

Thwaites Glacier is a massive region of the West Antarctic Ice Sheet on par with the size of Pennsylvania or the island of Britain and is over a mile thick in many places. It is currently retreating rapidly and is a likely candidate to contribute the most to rapid sea-level rise over the next few decades to a century.

That’s the most important point there is to make. I’m part of a large international team which is currently studying Thwaites Glacier for this very reason. But now, I’d like to tell you the story of my first field season in Antarctica as part of this team to collect reflection seismic data on Thwaites Glacier.

Hi, my name is Lizzy. I’m a PhD candidate at Penn State University, in State College, PA, USA. I’m a geophysicist; More specifically, I work on glaciers using seismic methods. I became very interested in geo- and climate-sciences towards the end of my undergraduate degree in physics, and decided I wanted to pursue a career track that would let me study glacial systems. I started with a master’s degree in marine science, where I studied sediment deposits in Prince William Sound Alaska related to climate, glacial, and earthquake activity. This was awesome, but with my background in physics, I wanted a bit more ‘physics-y’ stuff in my work. I thus entered into a PhD program with Sridhar Anandakrishnan and Richard Alley to learn about seismic methods on glaciers! They got me onboard a wonderful, globally collaborative project known as the International Thwaites Glacier Collaboration (ITGC).

Left: Me in front of Sólheimajökull, Iceland. Right: The GHOST ITGC crew on Sólheimajökull, Iceland.

The ITGC aims to study as many aspects of Thwaites Glacier as possible, from the interior to the sea, to the models! As part of the ITGC, I became involved in the MELT and GHOST projects. Such large, international projects require a lot of time, money, and planning! My first major excursion was a trip to Iceland where the GHOST team members from around the world met up for 5 days in the small town of Vic to hash out the details for our upcoming field seasons. This was an eventful, tiring, and amazing experience! The team made sure to do a bit of sightseeing between the meetings. We made it out to a glacier called Sólheimajökull!

Fast forward to the Antarctic 2019-2020 Field season. One season spans the northern hemisphere winter (since it’s summer down below). I was going down for my first time to participate in the MELT fieldwork, located on the grounding zone of Thwaites Glacier! This is a region where the ice goes from sitting on bedrock/sediments (grounded) to floating over ocean water (ungrounded/ice shelf). Such regions can be dangerous (they are dynamic and can be heavily crevassed) but are also critical data-gap areas which need to be studied. Luckily, the supporting organizations and field members spend a lot of time and effort to choose camp sights: safety first!

So how does one GET to the most remote location on the planet with a ton of camping and science equipment in tow? First, you need to reach a country which has planes or vessels that make the trip down. For Americans, this is generally Christchurch, New Zealand.

Spring was in full bloom in Christchurch, NZ, which still suffers from damages from the 2011 earthquake.

In Christchurch, I needed to undergo some training, pick up my ‘extreme cold weather’ gear (ECW), and wait… and wait… and wait. Flights down to McMurdo Station, Antarctica, happen aboard C-130 Hercules (‘Hercs’) aircraft and are approximately an 8-hour flight. Taking off from Christchurch is rarely an issue but the weather must be good on both ends. Frequently the weather is no-good for landing in McMurdo and the planned flights are delayed or cancelled. To make matters worse, you may end up ‘boomeranging,’ whereby you get onboard and flight, take off, and the weather turns partway through, hence requiring you to fly all the way back to Christchurch to try again another day. Fortunately, Christchurch is an incredible place to spend the summer, so you may not be waiting for too long at least. I ended up only having to wait one extra day. The flight down is cramped and uncomfortable, but that can’t avert the excitement!

Example of a Hercules C-130, along with pictures of the ‘seating’ inside! It couldn’t stop me from being excited!

Once you arrive in McMurdo as a beaker (the affectionate name given to the scientists by the ‘townies’) there’s a whirlwind of training sessions to be had. How to throw out your trash responsibly, where’s your dorm, how to use a ski-doo, how to camp on the ice, where do you go to eat, how to walk without slipping, don’t touch the penguins, don’t fall in a crevasse… the list goes on! There is also a ton of packing that needs to be done! One needs to pick up their tent and sleeping gear, safety gear, skis, scientific equipment that was shipped down, and more. Of course, there’s a good chance your flights out of McMurdo to your next station will also be delayed (much for the same reasons as above), so you’ll likely still have a chance to do some fat-tire biking, hiking, skiing, see some talks, have some beer, or enjoy a nice coffee! There’s even a small gym to workout, or a library if you need a space to work. I chose to hike.

Top to bottom: McMurdo, view of the Royal Society Range from ‘downtown’ McMurdo, view from my dorm.

The next destination of ITGC was the WAIS divide: The centre of the West Antarctic Ice Sheet. Getting to WAIS divide is a similar, albeit shorter, flight on a Herc. When you arrive, the jovial crew which runs the place (usually only a dozen people or so) will happily welcome you. The ‘arrival training’ here is generally a 10-minute rundown of where to find the toilets and where to pitch your tent (in ‘tent city’). It’s super exciting to finally be on the ice! If you’re willing to shovel snow into a melter, you can even have running, hot water to wash your hands, brush your teeth, take a hot shower (a god-send after you return from the field) and even do a load of laundry if you need to… but you’ll need to shovel at least 3 buckets for that. Here we run our final checks on all the equipment and gear we are bringing, loading it on to a small fixed-wing aircraft (think Arctic bush-pilot!), and helping with daily tasks around camp (shovelling snow for water and washing dishes, usually). Otherwise, we kill time waiting on, yet again, weather windows for our final flights to our field stations on Thwaites Glacier.

The main module of WAIS divide station, with an inset of ‘tent city’ where everyone sleeps. Bottom: the water melter, bucket, and running water setup at WAIS divide.

A 2-hour flight on a Twin Otter later, we finally arrived at MELT camp on the grounding zone. We set up our sleep tents alongside the main tent. The placement is very deliberate: You want them close enough that you can still see the next tent in a storm, but far enough that snowdrifts from each tent don’t bury their neighbours! The main tent was (thankfully) tall enough to stand up straight! Depending on the number of personnel in your camp, that’s not always the case! I slept in a Scott Tent, named after the explorer who first used this design in Antarctica. These are bright orange both to increase visibility and to create a warmly-lit environment inside. Ours also came with nifty lines on which to hang our soggy gear every night before bed.

Pictures of the tents, campsite, and aircraft frequently visiting MELT camp.

I ended up spending three weeks living in a tent, without running water (no bathing or handwashing!) at Thwaites’ grounding zone. Our crew was comprised of two mountaineers, whose main goals were to keep the camp running and safe, oceanographers, whose goals were to drill through the ice sheet and take oceanographic measurements and deploy the ICEFIN robot, a BBC news crew gathering information for documentaries and articles, and two seismologists: myself and Kiya Riverman! We spent our days collecting reflection seismic data to profile the thickness and shape of the ice shelf, water column thickness changes, and the topography and acoustic impedance of the bed beneath the ice and water.

If you have never collected reflection seismic data on ice, it is BRUTAL! Reflection seismic is a method where a line of seismic detectors is lain out and a controlled explosive source is set off. The seismic energy from source radiates through the subsurface, reflecting off various boundaries (between ice, water, and sediment/rock in our case) and is measured by the detectors at the surface. We used a 480 m long cable with small, simple seismometers known as geophones and geo-rods connected every 10 m. Every detector needs to be buried in a hole 1 m deep, and the explosive ‘shot’ buried in a hole 5 m deep. Our goal was to collect as many continuous kilometres of data as possible. This entails dragging and placing a half-kilometre long cable behind a ski-doo, digging 48 holes, placing 48 detectors, digging and burying the shot hole, shooting and collecting the data, then unburying and collecting the detectors, and starting from the beginning again… It gets tedious and exhausting pretty quickly. Things are always breaking or malfunctioning, and you’re always at the whim of the weather. It went from above freezing on some days to well below on other days, and these changes occurred within the same day. This meant the surface snow was constantly fluctuating between freezing and thawing. Imagine having to dig 48, 1 m deep holes through solid ice (it’s certainly not powder) two to three times a day.

In the end, we successfully collected several kilometres of seismic line over grounded and floating regions. The oceanographers and ICEFIN crew were able to deploy various stations on and below the ice, and the ICEFIN robot made several successful dives, swimming to different regions of the grounding zone and ice shelf while capturing video footages and oceanographic measurements. By mid-January, the crew and equipment began to pull out throughout several flights (small aircraft can only take so much weight, and they also need weather windows). I was eager to get out: all of the travel, physical labour, and constantly being on the hook for flights due to weather issues had stressed me out a lot. My trip out was swifter than my way in, but I still had to spend several days at WAIS divide waiting for a flight to McMurdo. The wonderful team at the National Science Foundation headquarters in McMurdo was able to get me a seat on the next available outbound Herc, and I made the trip back to State College, Pennsylvania, USA in under 2 days! There’s nothing quite like coming home to your partner and pets after a trip to Antarctica!

If you want to know more about Thwaites Glacier, visit the ITGC website linked above. If you want to know more about MELT camp, here are some great articles and clips from the BBC and PBS news!

This blog post was written by Elisabeth Clyne a PhD candidate at Penn State University
with revisions from ECS representative Michaela Werner and Maria Tsekhmistrenko.
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