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fieldwork

Weathering the storm from a research vessel

Weathering the storm from a research vessel

Fieldwork can take geoscientists to some of the most remote corners of the Earth in some of the harshest conditions imaginable, but stories from the field hardly make it into a published paper. In this blog post, Raffaele Bonadio, a PhD student in seismology at the Dublin Institute for Advanced Studies in Ireland, shares a particularly formidable experience in the field while aboard a research vessel in the North Atlantic Ocean.  

We knew it would be stormy that night. At the previous evening’s briefing, the captain of the ship, composed and collected, notified us that we needed to make a diversion from the planned route to avoid getting too close to the eye of the storm, “We’ll slow down the vessel…” “kind of five metres swell expected”. He was calm and comfortable. The crew members were calm and comfortable. We, the guest scientists, were not.

Why were we in the middle of the ocean?

I was part of a team of researchers from the Dublin Institute for Advanced Studies working on the project SEA-SEIS (Structure, Evolution and Seismicity of the Irish offshore). Our task was to deploy a suite of seismometers on the bottom of the North Atlantic Ocean from our research vessel, the RV Celtic Explorer, to investigate the geological evolution of the Irish offshore.

A map of the North Atlantic Ocean, showing the locations of seismometers deployed by the team’s research vessel, the RV Celtic Explorer. Credit: Raffaele Bonadio

Why study the Irish offshore?

The tectonic plate that Ireland sits on was deformed and stretched to form the deep basins offshore. The plate then broke, and its parts drifted away from each other, as the northern Atlantic Ocean opened. Hot currents in the convecting mantle of the Earth caused volcanic eruptions and rocks to melt 50-100 km below the Earth’s surface. These hot currents may have come from a spectacular hot plume rising all the way from the Earth’s core-mantle boundary (at 2891 km depth) to just beneath Iceland.

What do ocean bottom seismometers do?

Ocean bottom seismometers record the tiny vibrations of the Earth caused by seismic waves, generated by earthquakes and ocean waves. As the waves propagate through the Earth’s interior on their way to the seismic stations, they accumulate information on the structure of the Earth that they encounter. Seismologists know how to decode the wiggles on the seismograms to obtain this information. With this data, they can do a 3D scan (tomography) of what’s inside the Earth.

One of the research team’s seismometers being dropped into the North Atlantic Ocean. The instruments sink to the bottom of the ocean, where they measure the Earth’s movement. Credit: SEA-SEIS Team

In this project, we want to better understand how the structure of the tectonic plate varies from across the North Atlantic and what happens beneath the plates. And is there an enormous hot plume beneath Iceland, responsible for the country’s volcanoes today and the formation of Giant’s Causeway in Ireland? This is what we hope we will find out!

Experiencing an ocean storm

We were aboard the ship about 9 days and had just deployed “Ligea”, the 14th seismometer before the captain had notified us that a storm was heading our way.

While we were told in advance of the approaching storm, there was no way we could have imagined what it would be like to be in the middle of a stormy ocean. I had only heard some stories and I didn’t fully believe them…

I was awakened by the sound of my table lamp smashing on the ground, even the 15 cm protection edge around the table couldn’t help. The closet door opened and hit the wall. I managed not to fall off the bed, pointing my legs and make a crack with my back. I heard one of my colleagues laughing in the next cabin after a loud thud. “Did he just fall off the bed?” I thought to myself – his laugh did sound a bit of hysterical.

I realized a big wave had crashed on the side of the ship. I couldn’t believe that water and metal crashing together could make such a harsh bang. The previous evening was a continuation of bangs, splashes, sprinkles, bloops, clangs, and creaks … but even with all these noises and disturbances, I managed to sleep, exhausted from dizziness and sea-sickness.

I checked the clock on the wall: it was 3:20 in the morning. I looked at the porthole, due to the vertical movement my cabin was underwater half of the time. I walked through the cabin, trying to reach the toilet. “Oh, I wish they made the cabin smaller! I can’t reach both walls with my arms,” I said to myself. I opened the tap to refresh my face, the flowing water danced right and left across the basin. I then climbed up to the deck, I had to literally climb up the stairs. Up there I couldn’t see anything but darkness; I couldn’t see the boundary between the sky and the sea.

More than a week had passed since our departure, yet my body had still not adapted to this incessant movement. My eyes could not follow my body and my stomach did not react well, I couldn’t see anymore what was horizontal and what wasn’t. However, I wasn’t even scared, I believed nobody on the ship was (or is it only that I wanted to believe this?). It wasn’t fear, but rather an unceasing uncomfortable feeling: I knew I was more than 900 km from any dry land, in the middle of the North Atlantic Ocean, on a 66 m long vessel; I knew the captain and the crew were working hard to take us far from the storm. I was not scared…

In a few hours we were planning to deploy an ocean bottom seismometer, a very sophisticated device that is able to operate at huge pressures at the bottom of the ocean; released from the ship it would sink and install itself on the seafloor 4 km under the surface of the waves. In other words, a 200 kg ‘little orange elephant’, as the students who supported us from land every day liked to call it! “Will we be able to deploy? Will we be able not to crash the instrument on the sides? Will we instead be able to keep our balance and walk up to the deck?”

“Yes, we will.”

How did this look like? Find out more in this video:

 

So, what did we accomplish?

As part of the SEA-SEIS project, led by Dr. Sergei Lebedev, our research team successfully deployed 18 seismometers at the bottom of the North Atlantic Ocean. The network covers the entire Irish offshore, with a few sensors also in the UK and Iceland’s waters. The ocean-bottom seismometers were deployed between 17 September and 5 October, 2018, and will be retrieved in April of 2020.

To find out more about the SEA-SEIS Projects, have a look at SEA-SEIS or check out our introductory video.

By Raffaele Bonadio, Dublin Institute for Advanced Studies, Ireland

Imaggeo on Mondays: Air samples from afar

Imaggeo on Mondays: Air samples from afar

I’ve taken many photos on fieldwork, everywhere from Malaysia to Antarctica but this particular photo was taken in my ‘home’ lab at the University of East Anglia (UEA) in Norwich, UK. Atmospheric scientists collect air samples canisters such as these from around the world: from high altitude research aircraft (such as the Geophysica), long-term measurement time series (such as Cape Grim) or field campaigns in urban and rural environments.

At UEA we measure these whole air samples for a suite of up to 50 trace gases, covering all the major ozone depleting substances and non-CO2/CH4 greenhouse gases. We measure compounds at ‘parts per trillion’ (ppt) level or below in samples as small as 20 ml. It’s very hard to visualise 1 ppt… but it’s equivalent to about one second in 32,000 years measured in a sample that could fit in an egg cup.

Often these air samples are also analysed at other labs in Europe and other parts of the world, adding to the total number of compounds and isotopes we can quantify. Samples such as these have helped us identify new threats to ozone recovery and to quantify emissions of climatically-important trace gases such as HFCs and PFCs. To measure such trace, trace gases requires an instrument that is both large and temperamental. As such, it doesn’t (well can’t) leave the lab and we bring all the samples back to it. Stopping to imagine where the samples came from and how rare and special they can be (air from 30 km high or from deep in an ancient ice core!) helps me get through the long and labour intensive days in the laboratory.

By Emma Elvidge, University of East Anglia, UK

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

Last chance to enter the EGU Photo Competition 2019!

Last chance to enter the EGU Photo Competition 2019!

If you are pre-registered for the 2019 General Assembly (Vienna, 7-12 April), you can take part in our annual photo competition! Winners receive a free registration to next year’s General Assembly! But hurry, there are only a few days left to enter!

Every year we hold a photo competition and exhibit in association with our open access image repository, Imaggeo, and our annual General Assembly. There is also a moving image competition, which features a short clip of continuous geoscience footage. Pre-registered conference participants can take part by submitting up to three original photos and/or one moving image on any broad theme related to the Earth, planetary and space sciences.

Shortlisted photos will be exhibited at the conference, together with the winning moving image, which will be selected by a panel of judges. General Assembly participants can vote for their favorite photos and the winning images will be announced on the last day of the meeting.

How to enter

You will need to register on Imaggeo to upload your image, which will also be included in the database. When you’ve uploaded it, you’ll have the option to edit the image details – here you can enter it into the EGU Photo Contest – just check the checkbox! The deadline for submissions is 15 February.

Previous winning photographs can be seen on the 201020112012,  201320142015, 2016, 2017, and 2018 winners’ pages.

EGU 2019 will take place from 07 to 12 April 2019 in Vienna, Austria. For more information on the General Assembly, see the EGU 2019 website and follow us on Twitter (#EGU19 is the official conference hashtag) and Facebook.

Imaggeo on Mondays: An iceberg-sized issue

Imaggeo on Mondays: An iceberg-sized issue

This was taken during a study, undertaken by me and my colleagues, on the sea ice of McMurdo Sound, Antarctica. We designed the project to document how supercooled water carrying suspended ice crystals flows along its pathway towards the open ocean. Ultimately, this work aims to assess the Ross Ice Shelf’s contribution of local melt to the long-term trend of increased sea ice cover around Antarctica – a signal which has been dominated by expansion in the Ross Sea.

However, over the winter prior to the field season an iceberg, 12 kilometres long and 1 kilometre wide that had calved from the Ross Ice Shelf, grounded itself across the middle of our intended study region. This created a significant constriction to the flow, as the iceberg forced the approximately 30 km-wide plume to squeeze into half of that space.

We quickly modified the objectives for the field season to take advantage of this, adding an element focusing on the fluid dynamics of accelerated large-scale flow around the tip of the iceberg, and another on the thermodynamics of the supercooled plume interacting with a deep wall of ice. These adjustments to our study required drilling several holes through the sea ice along lines that approached the iceberg from two different directions to collect the necessary oceanographic data.

The iceberg towers about 40 m above the frozen sea surface, with our field support team providing scale as they scope a route of safe approach. However, hidden from sight by the sea ice, the iceberg stretches a further 170 m below the surface to the point where it is grounded on the seafloor.

Conducting field science in Antarctica requires being able to adapt to a dynamic environment. In this case, our flexibility was rewarded with a unique data set – essentially a laboratory study in fluid mechanics on a real-world scale.

By Natalie Robinson, New Zealand National Institute for Water and Atmospheric Research (NIWA)

If you pre-register for the 2019 General Assembly (Vienna, 07–12 April), you can take part in our annual photo competition! From 15 January until 15 February, every participant pre-registered for the General Assembly can submit up three original photos and one moving image related to the Earth, planetary, and space sciences in competition for free registration to next year’s General Assembly!  These can include fantastic field photos, a stunning shot of your favourite thin section, what you’ve captured out on holiday or under the electron microscope – if it’s geoscientific, it fits the bill. Find out more about how to take part at http://imaggeo.egu.eu/photo-contest/information/.

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.