GeoLog

Seismology

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

April GeoRoundUp: the best of the Earth sciences from the 2019 General Assembly

April GeoRoundUp: the best of the Earth sciences from the 2019 General Assembly

The EGU General Assembly 2019 took place in Vienna last month, drawing more than 16,000 participants from 113 countries. This month’s GeoRoundUp will focus on some of the unique and interesting stories that came out of research presented at the Assembly!

Major Stories

Glacial disappearing act in the European Alps

New research from a team of scientists estimated the future of all glaciers within the European Alps, and the results aren’t that hopeful. After running new simulations and analysing observational data, the researchers predict that, if we limit global warming below 2°C above pre-industrial levels, by 2100 glacier volume in the Alps would be roughly two-thirds less than levels seen today.

Furthermore, according to the new research, if we fail to put global warming in check, more than 90 percent of Europe’s glacier volume in the Alps will disappear by the end of the century. “In this pessimistic case, the Alps will be mostly ice free by 2100, with only isolated ice patches remaining at high elevation, representing 5 percent or less of the present-day ice volume,” says Matthias Huss, a researcher at ETH Zurich and co-author of the study.

Evolution of total glacier volume in the European Alps between 2003 and 2100. Credit: Zekollari et al., 2019, The Cryosphere.

The data also suggests that from now until 2050, about 50 percent of the present glacier volume will melt, regardless of how much greenhouse gas emissions we produce in the coming years. This is because glaciers are slow to respond to changes in climate conditions, and still reflect colder climates from the past. In addition to presenting their research at the EGU General Assembly, the team also published the results in The Cryosphere.

The search for the oldest ice announces their drill site

Ice-core extraction near Concordia station (Credit: Thibaut Vergoz, French Polar Institute, CNRS)

After three years of careful consideration, a collection of European ice and climate researchers have pinpointed the spot where they would most likely uncover the oldest ice core possible, one that dates back to 1.5 million years from today.

The consortium of researchers, also known as the Beyond-EPICA project, hopes to pull out a sample of ice containing a seamless record of Earth’s climate history. Such ice samples contain trapped air bubbles, some sealed off thousands to millions of years ago, thus providing undisturbed snapshots into Earth’s ancient atmospheres. Using this climate data, researchers can make predictions on how Earth’s will warm in the future.

At the General Assembly, the scientists formally announced that the drilling operation will be conducted 40 kilometres southwest from the Dome Concordia Station, which is run jointly by France and Italy. The team plans to collect a three km-long ice core from the site, nicknamed ‘Little Dome C,’ over the course of five years, then will spend at least an additional year examining the ice.

Map of Antarctica showing the areas surveyed by BE-OI and the selected drill site (Credit: British Antarctic Survey (BAS))

 

What you might have missed

Predicting the largest quakes on Earth

Scientists have long discussed how intense quakes can be on Earth, with some studies suggesting that Earth’s tectonic features cannot generate earthquakes larger than magnitude 10. However, new research conducted by Álvaro González Center from Mathematical Research in Barcelona, Spain estimates that subduction zones, regions where one tectonic plate is pushed under another, subsequently sinking into the mantle, have the potential to release 10.4 magnitude earthquakes. González’ analysis suggests that such events happen on average every 2,000 years.

“Such events would produce especially large tsunamis and long lasting shaking which would effect distant locations,” Gonzalez said to the Agence France-Presse.

His findings also propose that large asteroid impacts, such as the dinosaur-killing Chicxulub event 66 million years ago, may trigger even larger magnitude shaking. According to data analysis, shaking events reaching magnitude 10.5 or more likely happen on average once every 10 million years.

Where deadly heat will hit the hardest

Heatwaves and heat-related hazards are expected to be more prevalent and more severe as the Earth warms, and a team of researchers looked into which regions of the world will be the most vulnerable.

The scientists specifically analysed human exposure to ‘deadly heat,’ where temperatures as so high that humans aren’t able to cool down anymore. By examining data projections for future population growth and annual days of deadly heat, the researchers assessed which areas will be hit the hardest. They found that, if global warming isn’t limited to 2°C above pre-industrial levels, there will be a few ‘hots spots,’ where large populations are predicted to experience frequent days of deadly heat annually.

Dhaka, Bangladesh, is expected to experience significant exposure to deadly heat in the future, according to research presented at the EGU 2019 meeting. Credit: mariusz kluzniak via Flickr

The research results suggest that future deadly heat will most significantly impact the entire South Asia and South-East Asia region, Western Africa and the Caribbean. Sub-Saharan Africa in particular will experience big increases in deadly heat exposure, due to climate change and population growth.

The researchers also found that a minority of large cities in very poor countries will be the most affected by future heat conditions. “There is a big inequality of who takes the toll of deadly heat,” said Steffen Lohrey, a PhD student at the Technical University Berlin who presented the findings at the EGU meeting.

Europe and the Mediterranean at risk of malaria due to climate change

While malaria was eradicated in Europe and the Mediterranean in the 20th century, there have been an increasing number of new cases in this region of the world, primarily due to international travel and immigration. New research presented at the General Assembly by Elke Hertig, a professor at the University of Augsburg, Germany, suggests that Europe’s future climate may further increase the risk of local malaria recurrence and expansion.

Malaria is transmitted to humans by Anopheles mosquitos and these disease-carrying insects are very sensitive to temperature and precipitation conditions. In particular, these mosquitos thrive in areas with warm spring temperatures and high precipitation in the summer and autumn.

Using climate models, Hertig found that the malaria-carrying mosquito population will likely spread northward as Europe’s climate changes, reaching much of northern Europe by the end of the century. Alternatively, her models suggest that mosquito populations will decline in the Mediterranean regions, mainly due to decreases in summer and autumn rainfall.

A statistical analysis also revealed that, by the end of the century, disease transmission from mosquitoes will be the most effective in southern and south-eastern European regions, including parts of Spain, southern France, Italy, Greece, and the Balkan countries.

Other noteworthy stories

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Winners of the EGU Best Blog Posts of 2018 Competition

Winners of the EGU Best Blog Posts of 2018 Competition

There is no doubt that 2018 was packed full of exciting, insightful and informative blog posts. An impressive 382 posts were published across the EGU’s official blog, GeoLog, as well as the network and division blogs!

In December, to celebrate the excellent display of science writing across the network and division blogs, we launched the EGU Blogs competition. From a list of posts selected by our blog editors, we invited you, the EGU Blogs readers, to vote for your favourite post of 2018. We also invited EGU division blog editors and office staff to take part in a panel vote. After more than two weeks of voting, the winners are finally in!

Without further ado, we’d like to extend a big congratulations to the Geodynamics (GD) Division Blog, winner of the public vote, and the Geology for Global Development (GfGD) Blog, winner of the panel vote!

The GD division blog was crowned winner of this year’s public vote for their post on the Global Young Scientists Summit (GYSS) in Singapore! Follow blog contributor Luca Dal Zilio’s experience attending this gathering of over 250 PhD and postdoctoral fellows!

The GfGD blog snagged first place in the panel vote with their post: The Case Against Fieldwork – How can we internalise the carbon cost of fieldwork, as scientists who investigate the earth system? Read blog contributor Robert Emberson’s analysis and personal experience with the carbon footprint of working in the field!

All the posts entered into the competition are worthy of a read too, so head over to the poll and click on the post titles to learn about a variety of topics: from social media responses to geomagnetic activity, to exploring what artificial intelligence can do for climate science and watching socio-hydrology on Broadway.

If the start of a new year, with its inevitable resolutions, along with the range and breadth of posts across the EGU Blogs have inspired you to try your hand at a little science writing then remember all the EGU Blogs welcome (and encourage!) guest posts. Indeed, it is the variety of guest posts, in addition to regular features, which makes the blogs a great read! If you would like to contribute to any of the network, division blogs or GeoLog, please send a short paragraph detailing your idea to the EGU Communications Officer, Olivia Trani at networking@egu.eu.

Looking back at the EGU Blogs in 2018: a competition

Looking back at the EGU Blogs in 2018: a competition

The past 12 months has seen an impressive 382 posts published across the EGU’s official blog, GeoLog, as well as the network and division blogs. From an Easter-themed post on the convection of eggs, features on mental health in academia, commentary on the pros and cons of artificial coral reefs, advice on presenting research at conferencesthrough to a three-part “live-series” on the Arctic Ocean 2018 expedition, 2018 has been packed full of exciting, fun, insightful and informative blog posts.

EGU Best Blog Post of 2018 Competition

To celebrate the excellent display of science writing across the network and division blogs, we are launching the EGU Blogs competition.

We’ve asked our blog editors to put forth their favourite post of the year in the running to be crowned the best of the EGU blogs.  From now until Monday 14th January, we invite you, the EGU Blogs readers, to vote for your favourite post of 2018. Take a look at the poll below with the shortlisted posts, click on the titles to read each post in full, and cast your vote for the one you think deserves the accolade of best post of 2018. The post with the most votes by will be crowned the winner of the public vote. EGU blog editors and staff will also choose their favourites; the post with the most votes from this group will be deemed the winner of the panel vote.


New in 2018

Not only have the blogs seen some great writing throughout the year, they’ve also continued to keep readers up to date with news and information relevant to each of our scientific divisions.

The portfolio of division blogs has expanded this year, with the addition of the Natural Hazards (NH) and the Stratigraphy, Sedimentology and Palaeontology (SSP) blogs last December and March respectively. Since then, they’ve featured posts on many interesting topics, including xenoconformity, research on how bacteria slime can change landscapes, documenting the lives of people exposed to volcanic risk, and geoethics.

Get involved

Are you a budding science writer, or want to try your hand at science communication? All the EGU Blogs, from GeoLog (the official EGU blog), through to the network and division blogs, welcome guest contributions from scientists, students and professionals in the Earth, planetary and space sciences.

It couldn’t be easier to get involved. Decide what you’d like to write about, find the blog that is the best fit for your post and contact the blog editor – you can find all editor details on the individual blog pages. If in doubt, you can submit your idea for a post via the Submit a Post page on GeoLog, or email the EGU Communications Officer, Olivia Trani, who can help with initial enquiries and introduce you to individual blog editors.

Don’t forget to a look at the blog pages for a flavour of the content you can expect from the new, and existing, blogs in 2019. The blogs are also a great place to learn about new opportunities, exciting fields of research and keep up to date with news relating to the upcoming 2019 General Assembly.

Editor’s note on the EGU Best Blog Post of 2018 Competition: The winning post will be that with the most votes on 14th January 2019. The winner will be announced on GeoLog shortly after voting closes. The winning posts will take home an EGU goodie bag, as well as a book of the winners choice from the EGU library (there are up to 3 goodie bags and books available per blog. These are available for the blog editor(s) – where the winning post belongs to a multi-editor blog, and for the blog post author – where the author is a regular contributor or guest author and not the blog editor). In addition, a banner announcing the blog as the winner of the competition will be displayed on the blog’s landing page throughout 2019.