A plan B was activated in 2022 when we failed in the attempt of acquiring in-situ stress data for constraining spatial stress field variations across seeping sites in the Fram Strait. The planets aligned for a successful plan B. Thanks to a great cooperation with Ifremer we got granted a proposal for taking Penfeld (the French cone penetration tool for academia).
French CPTu Penfeld being deployed by the crew on R/V Kronprins Haakon
We cruised well this time and I am tremendously grateful to the ship administration (IMR), the ship crew, the Penfeld team (Genavir), the CPTu scientists (Ifremer), PhD and post-docts (UiT and the University of Texas at Austin) for all the contributions to a successful research campaign.
We collected in-situ pressure, friction and resistance together with thermal data that will allow us constraining the mechanical properties of methane rich sediments at Arctic submarine slide settings. We will look for potentially weaker or overpressurized zones, prone to collapse and leakage.
It is recomforting to end a project with a positive outcome. Both the Captain and myself felt we had a revenge! We celebrated!
The Genavir, Ifremer, Texas Uni and UiT team on ice
When I was a kid and still followed my parents in road trips to enjoy Venezuela’s nature, my mother would keep us quiet by playing with us a game that, when I think about it, was a very rational game. One of us would tell some facts. The rest of us would reconstruct the story behind the facts by making questions. I still recall 2 of those stories, which I recently taught to my kids in a road trip in Norway.
Just as in this game we use facts from data and observations to reconstruct a story behind. There is more than one story that can fit the facts but one will be the closest to the truth. The Earth is so bast and inaccessible that geosciences rely significantly in this way of reasoning. Often, we can just content with being sufficiently close to a truth.
The SEAMSTRESS project wants to understand the processes behind seafloor degassing in the Arctic Ocean. Why is there methane coming out to the oceans today? When did it start to happen? What forces it?
The sediments under the ocean are fill with water and gas. In some sub-seafloor regions, there is more gas either because there is gas leaking from deeper into the Earth or because there are large amounts of microbial communities consuming organic matter near the seafloor.
Illustration by Frances Cooke (see post earlier this year)
Understanding the processes that control the release of gas from the seafloor to the oceans is critical for better modeling submarine avalanches (towards the possibility of predicting tsunamis accurately), deciding whether geological settings are suitable for sequestration of carbons (carbon capture and storage as a way of mitigating human controlled climate change), to understand the evolution of large marine ecosystems in the deep sea, and for better simulating scenarios of future global climate changes.
Getting data exactly from where the water and the gas start to be generated and follow these movement of fluids through sediment all the way to the seafloor is hardly possible. We therefore rely on data from sediments near the seafloor. In a research cruise in 2021 with our colleagues from Ifremer we gathered pressure and temperature data from the upper 10 meters of sediments beneath the ocean floor. The instrument to collect this type of data is called a piezometer and it is a thin, long rod (ca. 7 cm in diameter and 7 m long) that has mechanical sensors every meter. These sensors can measure the temperature in the sediment fluids and also differences in the pressure that fluids in the sediment are experiencing sidewise compared to the pressure caused by the column of water above. In sediments that have compacted slowly without any major change in sedimentation speed, the pores are well interconnected and the fluid inside the pores is all interconnected with the ocean column. This creates a stable pressure field and no differences in the pressure field are measured. Similarly, the temperatures in the sediments would normally increase with depth and stay relatively constant in an unaltered setting. When differences in pore pressures and temperatures are measured the fun starts: we can search for a fitting story.
In our experiment we leaved the piezometers to record data over 3-4 days at 6 different locations along the continental margin off the west Svalbard coast. We noticed that the pressure that resisted penetration of the instrument into the sediment was less and less as we moved farther away from Svalbard (closer to the mid-ocean ridge). This trend doesn’t seem to be explained by changes in the type nor size of the sediment grains. Interestingly the amount of gas that is currently being released from the seafloor along the investigated transect is also decreasing in the same direction. We believe this differences in pressures within the upper sediments are reflecting changes in the way gas is transported towards the seafloor. We infer a damage of the sediment cohesion due to a less focused (more expansive) migration of the gas through the pores of the sediment. This changes in the mode of gas transport appear to be determined by the property of faults and cracks in the Earth. Whilst larger and more open cracks allow focused and fast gas transport out into the ocean, less open cracks favor slower transport of gas laterally through the sediment which result in more damaging of the sediment itself. How the gas moves through the sediments, whether it creates cracks or if it damages the internal structure of the pores, are questions we can just try to answer via lab experiments, the type of inferences we do by interpreting surficial data, and by simulating gas transport mathematically. Every new data set interpreted brings us just closer to a reality about the Earth interior…
An active fluid flow system Vestnesa Ridge continuously releases methane from the seafloor onshore Svalbard, in the Fram Strait. Systems such as these can be investigated by a variety of methods, one of them being monitoring of seismic signals. Since we are talking about recording data from deep underwater more than 100 km from land, we need to have an instrumentation deployed locally to record all types of seismic “murmurs” that can tell us which areas are active, and how this activity changes over time. For this purpose, we deployed instruments called ocean bottom seismometers (OBS) from the deck of the ship directly in the areas with known methane release. OBSs fall freely to the sea bottom and continuously record signals connected to geological processes. However, these are not the only signals recorded. Ocean is not a huge reservoir of calm water and in this section of the Arctic, underwater currents “shake” the instrumentation and generate large amounts of noise (“tremor”). Another signals unwanted by us, but greatly appreciated in general, are caused by marine mammals singing to each other (e.g., blue and fin whales). Because we usually have many instruments recording at same time and we try to record at least a year’s worth of data, detection of local seismicity becomes a difficult task, and we need some ways to filter data first.
We tried to devise a method of recognizing signals using ever-so popular field of machine learning, specifically an algorithm called Random Forest. This method is relatively simple and involves a large number of objects called “decision tree”. A decision tree is a simple conditional statement, for instance like one below:
This is only an example, and obviously one such statement will not help us much, since there can be earthquakes shorter than 5 seconds, and noise can last longer than that. But Random Forest works with hundreds, and even thousands of such trees. To train it to recognize different signals, we selected manually several hundreds of examples of earthquakes, micro-seismic signals (referred as “SDE”) and noise. For each example, we calculated almost 200 hundred individual metrics, related to signal duration, amount of energy, frequency content, polarization etc. During the training, Random Forest algorithm tries to randomly find the relations between all these parameters and find the set (“forest”) of decision trees that works as best as possible for the training data. Based on the average result from each decision tree (“voting”), it assigns the signal to one of the final categories we created: earthquake, SDE or noise. In the recently published article, we found that this type of algorithm works very well with seismological data from OBS. We used the metrics that have been shown in the past to give accurate results in the landslide recognition and in volcano monitoring. The diagram below shows how well the trained model recognized all the signals it was trained on, and examples of the different signals we tried to differentiate.
Methane is a powerful greenhouse gas. We know that at least a quarter of today’s warming is driven by methane from human actions but what we are unable to quantify with certainty is the natural methane release from both terrestrial and marine environments. Here we focus on the release of methane from beneath the seafloor in the eastern Fram Strait, located west of Svalbard. Our study site Vestnesa Ridge – a boomerang shaped sedimentary drift formed by deposition of suspended current material where the north Atlantic current splits, slows down and is diverted westwards along the ridge. At Vestnesa Ridge, methane gas is stored beneath the surface, at a minimum depth of ~170m where it first collected and reached the seafloor at around 2 million years BP, coinciding with the onset of northern hemisphere glaciations. Above the minimum depth of the free-flowing gas (extending upwards to the seafloor), methane is stored as gas hydrate (frozen methane).
The Arctic is a very sensitive region to climate change and little is known about the mechanisms that control the release of ‘free’ methane through ‘mud-cracks’ beneath the seafloor, imaged using state of the art high resolution seismic acoustic technology. We apply edge-detection filters (much like in photography editing but instead in a 3-D volume) to extract specific details such as fractures or upwards/downwards concavity in the morphology of the seismic image. Here we identify the size and location of mud-cracks and buried fluid-release craters using such filters (also referred to in seismic data as ‘attributes’) and interpret from these structures the history of methane release during the last 1.2 million years (the most recent glacial periods). This paper investigates the amount of fracturing and resulting pockmarks (i.e. small 20m craters) beneath the seafloor, west of the ridge. We identify 2 major fractured events as leakage-prone intervals. We consider that highly fractured zones (using a ‘fracture density’ attribute) are linked to potentially multiple significant climatic events in the recent glacial past. Significant climatic events impact the system by either increasing ocean bottom temperatures or fracturing the sediments related to the repeated growth and retreat of icesheets – cycling between exerting/releasing pressure on the Earth’s crust. The mechanisms proposed, destabilize the system and dissociate frozen methane into fluids (i.e. water and ‘free’ gas). The fluids become mobile in the sediments forming pathways via the mud-cracks. Methane gas previously trapped in the sediment is released into the ocean which in turn releases pressure. The ‘mud-cracked’ sediments become self-sealing, eventually blocking the flow of fluids until the next climatic event. We also indicate in our study that after a significant release the system takes time to collect gas back into the system and to become pressurized once again. In summary, using information from the past, our study has implications for understanding how a changing Arctic in the future might affect sediment stability and carbon transport to the oceans and atmosphere.
Published in Frontiers in Earth Science in May 2023 (https://www.frontiersin.org/articles/10.3389/feart.2023.1188737/full)
Figure: Map of the study area (top), example of how the sediment looks like underneath the seafloor, and map of the mud cracks (black and white inset) revealed by mathematical relationships between seismic traces.HDI stands for highly deformed (sedimentary) intervals. These intervals correspond to time periods where pressure and temperature changes had a larger impact on the sediments below the seafloor than any other period of time.
The International Ocean Discovery Program (IODP) has been reuniting scientists around the world for decades to collect samples and data from the Earth interior all around the globe. The R/V Joides Resolution, the main research infrastructure used for this major scientific synergy, reaches soon the end of her life spam (c. 45 years of sailing). Its last expedition will be in the Arctic Fram Strait. More precisely, one of the key geological systems that will be investigated is the Vestnesa Ridge, the case study of the SEAMSTRESS project.
Expedition 403 will be the last one o the program https://iodp.tamu.edu/scienceops/expeditions/eastern_fram_strait_paleo_archive.html
The main goal of this expedition is to reconstruct the paleo archive of sediment sources, currents, major climatic transformation associated with glacial cycles, and even the archive of the interactions between plate tectonics and sedimentary evolution during the opening of the Fram Strait.
One of the specific objectives of the expedition (objective 6) is to study glacial and tectonic stresses and their effect on near-surface deformation and Earth systems dynamics in this Arctic, very important region of the Planet (i.e., the gateway of the Atlantic Ocean into the Arctic). The knowledge advanced during the SEAMSTRESS project and the project’s rational underpinned the development of this objective. We hope for a successful campaign that will reunite experts around the world to answer many exciting questions, but one that is crucial for SEAMSTRESS: does tectonic drift and glacial rebound generate stresses that affect the Quaternary strata, leading to sediment cracking, sliding and releases of large amounts of carbon into the ocean?
Let the effort to advance our understanding of complex Earth system interactions in the Arctic continue!
My name is Frances Cooke, I am a PhD student and I live in Tromsø. I work within a project called SEAMSTRESS which is affiliated with the CAGE institute at the Arctic University of Norway. CAGE is a centre of excellence for Arctic Gas Hydrate, Environment and Climate. SEAMSTRESS is funded by the Tromsø Research Foundation and the Research Council of Norway. Scientific outreach is an integral part of my work as a PhD student at the university of Tromsø. I am passionate about making science accessible to the public through public engagements like this talk today, so it is a pleasure to be here to give you an insight into what I do living in the Arctic.
Our main goal in CAGE is to study methane release from gas hydrates beneath the Arctic Ocean to understand the potential impacts on marine environments and global climate systems, while SEAMSTRESS investigates the processes controlling methane release at Arctic continental margins. I will show you in this talk how we go about achieving those goals.
First, where does methane come from? In the ocean (broadly speaking) methane comes from two sources. It is either: 1) biologically formed (biotic) – from the decomposition and subsequent burial of organic material, either in the top 10s of metres (biogenic) or 1000s of metres (thermogenic) below the surface. At greater depth we refer to the breakdown of organic matter as ‘thermogenic’ – as the process is thermally driven (temperatures are higher at greater depth) and sourced from hydrocarbons; or 2) formed by geologic processes (abiotic) through magmatic processes.
Gas is buoyant and always wants to move upwards towards the seafloor any way it can, it eventually reaches the surface of the seafloor, where it will escape into the seawater. That is, if it is not consumed by methane eating bacteria or converted back into gas hydrate – to name a few of the processes.
What is gas hydrate anyway? First we need to understand a bit about the gas hydrate stability zone – where does the gas hydrate exist? We can recover gas hydrate samples by core sampling. If we are lucky the core barrel penetrates into mud containing gas hydrate – and this is within the gas hydrate stability zone. It is generally (in my study area) in the upper 200m beneath the seafloor and around 400m above the seafloor into the water column (however in some parts of the world gas hydrate stability zones can be 500 to 600m – this is dependent on geothermal gradients – i.e. how hot sediments are with depth beneath the surface). In this setting temperatures are between 4 and 18 degrees Celsius. You may find it unusual that methane is frozen between these relatively high temperatures, but it can exist in this state because it is under pressure.
Once gas hydrate is recovered – this is what it looks like. Everyone who has recovered methane from a core sample has a go setting it alight. It is extremely satisfying to watch the ice burning slowly away in your hand.
Huge quantities of methane are stored worldwide as gas hydrate over continents in permafrost and over continental margins, and some deep sea areas in marine settings.
I will now take you on a journey, first starting in the Arctic, in Russia – Siberia, and Arctic Canada – Baffin island; then moving across to the Barents sea where I will talk about the early work CAGE undertook in the Barents sea. Then I will move out of the Arctic into the North Sea – a little closer to home (i.e. U.K) – where I will introduce the Tsunami that happened in the stone ages and its surprising connection to methane seepage. I will finish the talk by introducing a little about my PhD, my study area is located in a deep water setting – 1200m in the Fram Strait – between Svalbard and Greenland.
Time in geology is a bit like distance in astronomy – the numbers are so vast that it is difficult to make sense of them.
You are probably wondering what this is? It is just a stack of paper in the geology museum in Tromsø. It is made up of 22,700 sheets of A4 paper depicting the lifespan of the Earth. The final sheet of paper represents modern human existence.
In this talk we will also be focusing on a time period depicted by this last sheet of paper –the last 20,000 years, which geologically speaking is very recent times!
So what happened in the last 20,000 years? At 20,000 years we were coming to the end of the last ice age. During this time the ice was at its greatest extent, afterwards the ice started to melt and retreat. Then modern humans came into existence during a period called the Holocene period.
The Barents Sea methane release – that I will come to – started 12000 years ago and the North Sea submarine slide that caused a Tsunami event, happened around 8,200 years ago.
But first I will talk a little about what is happening today:
You’ve probably all heard about the permafrost melting in Siberia. Huge amounts of methane are expected to be released from permafrost this century because of warming.
Here is a photo of a village called Churapcha. This used to be an old airport runway but now the land looks more like bubble wrap. It is now a useless swampy field and it could eventually become a lake.
What you don’t see are these wedges of ice that form beneath the ground. They make up the permafrost. Each year the crack gets larger and over time the ice wedges become thicker. The black is an active layer that freezes and melts each year, but what is happening today, is that the white parts are also melting, releasing methane gas and causing the ground to subside in this bubble wrap pattern.
Now we move to Baffin Island – in Arctic Canada:
Here on this aerial photo subsidence has already taken place and the subsided land had since filled with water and the holes have become permafrost thaw ponds. The permafrost areas are vast.
The image to the right looks quite similar, but instead of looking down on the lad we are looking down on the seafloor – in the Barents Sea. Sonar data has been used to collect this information. The colour scale is water depth with blue the deepest and red shallow. There are clearly many craters here, some larger than a kilometer in size.
Now we focus entirely on the Barents Sea:
During the ice age the crater area was covered by a thick 2km ice sheet. When the ice sheets melted away, huge blow out craters formed. There was a sudden release (much like a lid being taken off a pressure cooker). The gas that had been trapped beneath the ice suddenly had somewhere to go, and it is still being release today (see flares on the figure).
What is interesting about this study is that we can use the melting of the Barents Sea ice sheet as an analogue for what may happen if the Greenland and west Antarctic ice sheets melt significantly in the future. We know that there are significant amounts of hydrocarbon gasses generated and stored beneath the ice there.
Now I am going to show you a reconstruction of the last ice age. This animated ice map was created by Henry Patton. He is an ice sheet modeler. The interactive graph in the top left shows the decline in ice volume in blue accompanied by an increase in sea level in green (from 20,000 years ago until 8000 years ago).
The animated map shows the Barents Sea ice disappearing 12,000 years ago, and it also shows the last of the ice disappearing from Norway around 8000 years ago.
This leads us nicely onto the next part – where I will speak about the North Sea Tsunami. It may have wiped out the last remaining part of Doggerland (which was Dogger Island) and the people living there!
Now onwards on our journey out of the Arctic and into the North Sea.
In 2006 I read a special report in the Independent newspaper with the title: ‘Tsunami horror hits Britain.’ This was not long after the Boxing day tsunami so it really made me want to read further and find out what this was all about.
The purpose of the article was to catastrophise what would happen in the year 2060 if nothing was done to prevent climate change, but in reality the article is slightly misleading. The methane bubble was not to blame for the catastrophic seabed slide, it was an effect rather than a cause. The cause of the Storegga slide and tsunami – or the trigger (however it is still debated) was an earthquake.
In the last 2.7 million years there have been cycles of cooling every 100,000 years, during these times ice ages took place.
The first cycle shows a deglacial period when there was a high amount of sediment loading (blue) – the blue sediments are deposited very rapidly and as a result are unstable (they haven’t had time to compact). The sediments are weak and act as a sliding plane. The second part of the cycle shows the ice sheet at its maximum extent, weighing down the continental margin. When the ice melts (stage 3) there is no longer a weight on the continental margin, and the land starts to rebound. This is when the earthquakes happen. So the slide was most likely triggered by a strong earthquake in the area and the unstable sediments on the slope then disappeared with the slide 8200 years ago.
So what about today? It is unlikely that another tsunami will happen at the Storegga slide area. Why? Because a new ice age with infilling of glacial sediments on to of marine clays in the slide scar would be needed to create a new unstable situation.
This illustration nicely summarises what happens once the earthquake has destabilized the sediment. The debris flow slips on the sliding plane (refer to blue sediments in previous slide) – made up of glacial marine muds. Within this layer are gas hydrates that are released, further triggering disability and sediment slip.
Now to the final part of the journey – we move back to the Arctic, into a deep water setting, 1200m beneath the ocean in the Fram Strait. Here I will introduce my PhD project.
The title of my PhD project is ‘Near surface (upper 300m) characterization of faults and fluid flow systems (i.e. the plumbing system beneath) at Vestnesa Ridge – east Fram Strait.’ My main research question is: ‘Why is gas seeping on the west of the ridge but not on the east?’ My aim: is to ‘Identify fluid (gas) flow features and structures that show sediment displacement across the ridge.’ My method/data used is: Seismic data (We use seismic data which is a sort of remote sensing that acquires images of subsurface features using technology that sends out a signal and records the signal that has echoed back. If you think of a baby scan, this is a similar technique.) My preliminary conclusion: ‘There is a spatial variation in the rate of sediment deposition across the ridge which may impact the density of small fluid flow escape features.’
How do we know what the plumbing system looks like beneath the seafloor? Here we have a seismic line across the sediment drift (Vestnesa Ridge). Beneath this structure, gas has accumulated and it seepage from one half of the structure (the east) – the ‘active’ area. Craters at the surface (aka pockmarks) give us clues about what is happening beneath the seafloor. Displacements (vertical black lines) in the seismic data beneath the coloured seafloor topology map (aka bathymetry) connect the free gas (arrows point to gas accumulation) to the surface of the seafloor.
I am investigating two different mechanisms controlling the gas seepage in the active and inactive part of the ridge. The ‘inactivity’ in the west refers to a drop in high methane seepage activity in the last few thousand years. A different process controls the release of methane in the west to the continued (last 2.7 Million years) high flux activity in the east. The process is referred to as low flux, and is much less studied. My current project focus is to investigate low flux seepage activity at the west of Vestnesa Ridge.
On the left (final slide) is my actual data within an illustration and to the right a conceptual model. Using seismic data I am documenting sediment deformation events that are confined to specific layers where pressure build up preferentially occurs. Gas may not be able to travel upwards because of different layer properties that act as seals. Gas may either travel horizontally in the trapped layers or form gas ‘turbation’ structures. Gas builds up in local pockets, mounds form and cracks form above the mounds. When the mound eventually collapses a crater is formed at the surface and the gas that is trapped locally escapes.
In the west the craters are preserved in clay sediments that are more likely to open under much less pressure. They are buried over time and we can observe them 100s of metres beneath the seafloor, as well as on the seafloor today. This tells us that the same processes have been occurring for millions of years.
We also know that the region is active with earthquakes because of the proximity to the mid-Atlantic ridge. Earthquakes can also facilitate movement of gas and gas escape in sediments that are extremely sensitive to even the smallest pressure perturbations. We can also factor in sediment deformation on account of post glacial adjustment. As a result of all these processes, sediment deformation is highly varied, and distributions of fractures are extremely intricate. The details are sometimes masked by disturbances/noise in the data, however the disturbances often provide clues to fluid movement.
To conclude: Gas hydrate is a frozen, naturally occurring and highly concentrated form of methane. Significant quantities of methane are stored worldwide as gas hydrate over continents in permafrost and over continental margins, in marine sediments where water depth exceeds 300m. The Arctic is a particularly sensitive region to methane release, widespread disappearance of Arctic near-surface permafrost is projected to occur this century because of warming.
Could decomposition of gas hydrates through increase in ocean temperature trigger abrupt climate change? This is debatable, but unlikely, particularly in deep water settings, given the depth of the gas hydrate stability zones. Bottom water temperature variations affect gas hydrates shallower than 1.6m below the seafloor – this is not deep at all! We should be most concerned about the melting of the permafrost and shallow water settings.
Will there be another North Sea tsunami? I consider this unlikely at the Storegga Slide area, at least within our lifetime. The Storegga type event takes place every ca. 100,000 years and is controlled by glacial cycles. However, we can only reanalyse when the next major event happens. Earthquakes can easily generate tsunamis, but you also need large quantities of sediments for a major event to happen.
I started my research career with a major entanglement of a wire into the propeller of R/V Professor Logachev in 2006 and I hope my career will not end as well with an entanglement.
My PhD project started with the participation in a research campaign at the mid-Norwegian margin co-organized by British, French and Russian teams. The aim was to conduct an ocean bottom seismic (OBS) experiment where 30 OBSs needed to be driven down to 730 m with a wire. One of the instruments drifted so much that the wire reached the propeller. That was the end of that instrument. The experiment was surprisingly a success.
We planned an offshore dilatometer experiment on R/V Kronprins Haakon in October 2021. The aim of the experiment was to measure, in-situ, the horizontal stress in the upper 20 m of sediment along the continental and oceanic margin west of Svalbard. What for? To see whether it is true that only vertical stress affects the upper part of the sediment packages deposited along continental margins. The main SEAMSTRESS hypothesis is that the motion of the plates at the mid-ocean ridge axes leads to compression of the entire crust against Svalbard, resulting in cracking of the upper sediment. This may cause shallower earthquakes, favor the release of large amounts of methane and promote submarine land sliding.
I was so exited. We managed to get a tender finished on time to hire the company that would provide the instrumentation for the measurements. I had the ship time, the funding and the instrumentation. It was supposed to be a great, unconventional, high risk high gain cruise. And then things happened…
To make the measurements we had a Cone Penetration Test (CPT) machine on board together with 2 expert engineers and the manager of the company that provided the service. The CPT is a heavy machine but the Captain of the ship had enthusiastically confirmed that the ship had strong winches to deal with such heavy machines: the trawling winches. The company never came back with hesitations or feedback about the type of winches that the captain suggested. To me all sounded like good news. What I didn’t know at that time is that I actually was not being wisely advised neither by the ship crew, experts with wires and winches, nor by the company, experts in deployment of their CPT. Before reaching the bottom at the first site of investigation (890 m), the wires got entangled and the experiment got to an end. Yes, as violent as it sounds. After months of work to get in place such an expensive and ambitious, beyond state of the art offshore experiment, it took only a couple of hours to culminate it with zero data.
The crew tried a few maneuvers but they did not manage to deal with the entangled wires so they cut and the instrument stayed at the bottom until 6 months later, Easter 2022, when we came back with the heroic ROV team to recover it.
I can tell the story now that I feel relieved because the company got back his machine. I would’ve not been able of telling the story before the 14th of April (day when the CPT was back on deck) because I was trapped inside a cloud of stress and anxiety. The company was asking for a random compensation on the lost of the machine. They claimed that the ship was responsible for the deployment, while the ship claimed that the company did not master their instrumentation properly. The responsibility stayed in a limbo and conveniently ended-up on the university (the project administrator). I tell it and I almost cannot believe it: the scientist hires instrumentation and expert operators of such instrumentation and hires the ship and its expert crew. None of the experts advised on the suitability of wires. The wrong wires are used. The experiment fails. The research project pays millions for “0” data and for the lack of professional advice by the experts.
A bit of a crazy thing, isn’t it? If you ask me, the decision on where the responsibility relies should have been taken on a trial. Instead, the project pays the mess and life keeps going without major dramas…
Life is life. At least I know more about wires, winches and legal processes.
Snap shot ROV video: The CPT at the bottom hosting two comfortable cods. The heroes in this story are UiB-Ægir and his pilots.
Why gas emissions from the seafloor have stopped thousands of years ago in some areas, while it persists exclusively on the eastern part of the Vestnesa sedimentary ridge? This is the question that drives our scientific objectives in the last research campaign planed under the SEAMSTRESS project.
The answer to this question is likely related to the type of sediment and the disposition of the sediment to fracture. To investigate this further we need to measure sediment properties such as in-situ pore fluid pressures, horizontal stress, shear strength. Conducting these measurements is not so easy because it requires expensive and technically challenging instrumentation. The SEAMSTRESS project assumes the challenge of conducting the geotechnical experiments that are lacking to understand the pressure behavior at deep marine seafloor seepage systems in our favorite Arctic laboratory: The Vestnesa Ridge. These challenging experiments are the core of SEMSTRESS which main objective is to advance knowledge on the pressure (stress) field that controls seafloor methane emissions.
In a collaboration with MSH – Marine Sampling Holland and the Marchetti laboratory we are planning to deploy the Medusa dilatometer designed by the Marchetti Lab to measure in-situ the pressure of the Earth at ease and therefore the horizontal stress. To deploy this instrument offshore there is need for a seafloor (sort of) rig. Our colleagues from MSH joined us onboard with their Geomil’s Manta 200 rig, an instrument designed for conducting cone penetration tests in the soil. Geomil started developing this type of instrumentation in the 30s to help the Netherland overcome a struggle with railway failures due to soft sediment.
Manta is a big machine, heavier than anything that has been deployed so far from R/V Kronprins Haakon. The machine also has a power supply requirement that differs from what the ship can provide. Our mission therefor starts with a few days in the fjord working hard to overcome all the technical challenges to get the machine ready for deployment before sailing offshore.
Photo: The Geomil’s Manta-200 rig for Cone Penetration Test (CPT) onboard R/V Kronprins Haakon. The MSH team together with the ship crew prepare the winches and solvent challenges with the power supply.
