McMurdo Day 56: Lower Erebus Hut

I WENT TO MT. EREBUS!!!!!

56 days into my time in Antarctica, and I finally got to do some field work on PASSCAL stations.

Ever since our POLENET field season got cancelled back in December, Avi and I have been trying to get approval for field work on Mt. Erebus. PASSCAL currently has 4 seismic sites on Erebus, and two of them have been offline for the last year. We no longer were going to be in West Antarctica, so we though this would be the perfect opportunity to fix the broken Erebus stations and collect the data from all sites.

Last week (on day 52), we finally got NSF approval to do the field work! We submitted a helicopter request immediately, which takes 3 days to go through the system (plus the helos don't fly on Sundays). I was not expecting the weather to be good enough to fly to Erebus, because good weather days there are rare, but magically amazingly wonderfully gloriously on Monday the weather was perfect and we got to fly!!

The PASSCAL team boards a 412 helicopter, ready to do some field work!

We had great views of the ocean -- look at how much the sea ice has broken up! This was solid white ice just a few weeks ago.

The week before our flight, Avi and I got completely prepared to go (hence why I've been so busy and blog posts have been more infrequent...). We used spare equipment from the POLENET stash that we brought down (now that it wouldn't be used for POLENET) and loaded the correct configurations on the dataloggers. Different experiments (e.g. POLENET and Erebus) use different config files to specify the sensor type used, sample rate of data, and what kind of information is telemetered.

We flew over our Castle Rock test site on the way there!

I took an excessive amount of pictures from the helicopter, as per usual.

We also did extensive research into what equipment was at the Erebus stations and looked at the State-Of-Health (SOH) data to try and determine potential problems (with help from the team back at PASSCAL, of course). This ended up being more difficult than it should have been, because the team who installed these sites in 2018/19 didn't do a very good job of taking notes. Because we weren't totally sure what we'd be facing, Avi and I did a lot of work to prepare ourselves for any possible situation.

Avi took an excessive amount of pictures as well. Here he is capturing Castle Rock.

The first site we wanted to visit was at Hooper's Shoulder. On Monday, the Helo Ops manager (Helicopter Operations) called us and asked if we'd like to work in 35 knot (40 mph) winds. We said not really.... so she moved our flight to Lower Erebus Hut, which had much better weather on Monday.

The helicopter passed up through a large cloud bank sitting at ~7000ft, encasing Hooper's Shoulder.

Lower Erebus Hut is at an elevation of about 11100 ft, but because the air pressure is lower at the poles, our bodies experienced an effective pressure elevation of about 13000 ft. Yikes. Especially after living at sea level in McMurdo and Christchurch for the past 2.5 months.

We landed and started unloading the helicopter. The 45lb toolkit that I was carrying with ease at sea level in McMurdo suddenly seemed as if it was made of lead. I was able to make it about 10 ft before having to stop and catch my breath.

Approaching Mt. Erebus.

Here's a map from the wall in the helo passenger terminal showing the location of Lower Erebus Hut.

The weather at Lower Erebus Hut was -28°C (-18.4°F), with no wind and no clouds. This is by far the coldest temperature I have ever experienced. My nose kept running, but the snot froze almost immediately. By the end of the day, my neck gaiter was 90% frozen snot and was not keeping my face very warm at all.

Lower Erebus Hut camp. The camp wasn't opened this year, but I might be staying here next season to work on the new Erebus project.

At Lower Erebus Hut, there are two PASSCAL stations, side by side. One station uses a broadband seismometer, which measures a broad band of frequencies (get it? hence the name). It's a very sensitive instrument and can pick up very small signals. The other station uses a strong motion sensor, which detects (get ready for it) strong motion in the ground, like large earthquakes. The broadband seismometer is too sensitive, and not as good at detecting big earthquakes because the signal gets clipped. We use both a broadband and strong motion instrument in tandem to get data from smaller vibrations, as well as large earthquakes.

Our two stations at Lower Erebus Hut. Broadband station (left) and strong motion station (right).

Each seismometer gets its own datalogger, modem, charge controller, battery bank, and solar panels. The broadband station was functioning mostly as expected; the only issue was that the charge controller was charging the batteries to too high of a voltage. We swapped the charge controller with a new, freshly programmed one. Then we checked to make sure all other systems were functioning correctly and called it good.

Looking inside the enclosure at the broadband station. It looks a bit of a mess. You can see some lithium batteries (black), the harddrive storing data (orange, upper left), and the broken charge controller before we swapped it (center).

Here I am servicing the broadband site. I couldn't work the laptop in my giant yellow gloves, so I just wore my thin liner gloves. My hands got SO COLD, and I had to alternate between using the laptop/writing and standing around with my hands in my pockets with handwarmers.

The strong motion site was the site with real trouble. It had been offline since last July, which could have been due to a power problem or telemetry problem -- it was hard to tell from the SOH data. At the site, Avi and I had to use our combined 10 years of physics and engineering experience to diagnose the problem: the antenna cable was unplugged.

We plugged it back in, and replaced the antenna and cable, plus the charge controller for good measure.

We called PASSCAL on the satellite phone so they could confirm that the station was back online.

Another interesting problem at the site: this station is set up next to an active volcano, which emits volcanic gases from vents and fumaroles. The corrosive volcanic gases have eaten away at the metallic connectors on the exterior of our enclosures and solar panels. The solar panels themselves were covered in a thin film from the gases, which I cleaned off with a rag.

Corroded connectors on the solar panel junction box.

Thin film on the solar panels. It wasn't impacting the solar panel performance yet, but I'm sure it could build up significantly if untouched for several years.

We serviced both sites without too much trouble in about 3 hours.

The PASSCAL team high-fives on Mt. Erebus after completing the first REAL FIELDWORK of the season!!!!!!

We cleaned up our toolbags and still had some time to explore around.

Me and Erebus!!

There are some extremely cool rocks right next to our stations.

Just down the hill from the camp were several ice fumaroles. The fumaroles emit volcanic gases, which contain water vapor. Because the air temperature is so cold (and always below freezing), the water vapor freezes instantly, creating these neat cone-shaped ice structures around the fumaroles.

A steaming ice fumarole. We were warned not to step on the snow around the fumaroles because "people have fallen through, 12-13ft down". So I stayed firmly on the rock.

Close-up of an ice fumarole.

I got to see the rocks made of Erebus' rare phonolitic lava up-close. Phonolite is an intermediate composition lava with low silica content (meaning no quartz forms), only found on Mt. Erebus and Mt. Kenya.

Mt. Erebus is known for "Erebus Crystals", which are these huge, well formed anorthoclase feldspar phenocrysts, showing the two planes of cleavage that distinguishes feldspars quite clearly. The crystals grow inside Erebus, and are ejected out encased in phonolitic volcanic glass. The volcanic glass weathers away faster than the feldspar crystals, leaving them behind. I saw so many just walking around Lower Erebus Hut.

A cool rock formation.

Up-close picture of a rock, with glove for scale.

While wandering around, we came across a crashed helicopter. Apparently, this helicopter was left here when it wouldn't start (helicopters have trouble starting at such high altitudes and in such cold temperatures). They came back the next day, and it had tipped over, so they just left it there. Thankfully no one was hurt, but it's pretty spooky looking all the same.

The abandoned helicopter says "USCG" (US Coast Guard) across the bottom.

All the wires are falling out of the front. Very spooky. Definitely haunted.

After exploring, we loaded up the helicopter and prepared to set off. After sitting for a few minutes the pilot informed us that the helicopter was having "difficulty starting". Then came the most nerve-wracking 5 minutes of my life as he tried to start the helicopter and I just kept thinking about the abandoned helicopter sitting just down the hill. But it finally started! And we took off safely!!

Me and the 412 helicopter!

I thought the day couldn't get any more amazing, but then the helicopter pilot flew us around the crater rim on the way out. Flying in a helicopter over an active volcano in Antarctica is definitely the coolest thing I have ever done. And I'm getting paid to do this work???

Mt. Erebus crater!! There's a lava lake behind all that steam!!

Here are some more pictures from the (short, 30 min) flight back to McMurdo.

Back down through the cloud layer.

Look at those huge crevasses!

Flying over the Erebus Glacier Tongue.

Pressure ridges on the Ross Ice Shelf.

Flying back over McMurdo. The giant blue building is the galley.

I am so unbelievably happy that I got to do some real fieldwork this season, and on Mt. Erebus of all places! I am so grateful for this job and all the amazing experiences I have been able to have (and will continue to have!).