Tree rings from old-growth Douglas firs on the Oregon Coast show evidence of 1700 tsunami

by Michelle Klampe, Oregon State University

A stand of old growth Douglas-firs near a pond in Mike Miller Park in South Beach, Oregon. Credit: Bob Dziak

Core samples taken from a stand of old-growth Douglas fir trees in the South Beach area just south of Newport showed reduced growth following the 9.0 earthquake and subsequent tsunami that struck the Pacific Northwest in 1700.

The physical evidence from the Douglas fir tree rings confirms modeling that depicts the reach of the January 1700 quake, which was the last major earthquake to hit the Cascadia Subduction Zone, said Robert Dziak, a Hatfield Marine Science Center-based scientist with the National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory.

"The tsunami appears to be the event that most affected the trees' growth that year," said Dziak, whose work includes ocean acoustic studies, signal analysis and tsunami modeling. He also holds a courtesy appointment in Oregon State University's College of Earth, Ocean, and Atmospheric Sciences. "Getting these little bits of the picture helps us understand what we might expect when the next 'big one' hits."

The findings were published recently in the journal Natural Hazards and Earth System Sciences.

The idea for the study dates back more than a decade; Dziak was aware of past research that had shown evidence of the 1700 quake in trees in Washington, and thought it might be worth seeing if similar evidence existed in Oregon.

The first challenge was finding a stand of old-growth Douglas firs in the tsunami inundation zone. The researchers looked at a few places before locating the stand in Mike Miller Park in South Beach, about two kilometers south of Yaquina Bay and 1.2 kilometers east of the present-day ocean shoreline.

"We're not sure why this tree stand wasn't logged over the years, but we're very fortunate to have a site so close to the coastline that has survived," said coauthor Bryan Black of the Laboratory of Tree-Ring Research at the University of Arizona, Tucson.

A new and updated tsunami model run by the researchers as part of the study shows that the area could have been inundated by up to 10 meters of water in the 1700 tsunami event, said Dziak.

Once the old-growth stand was identified, the researchers collected core samples from about 38 trees using a process that allows them to analyze the tree rings without damaging the overall health of the trees. The majority of the trees dated to around 1670, with one dating to 1650, Dziak said.

They analyzed the growth rates in the rings and compared the growth rates to those of other old-growth Douglas firs at sites not in the tsunami inundation zone. They found that in 1700 the trees in the tsunami inundation zone showed a significantly reduced growth rate.

Researchers are still working to figure out why the tsunami might have affected the trees' growth since the trees are relatively far from the shoreline. They suspect it may be a combination of the ground shaking from the earthquake and the inundation of seawater.

"The salty seawater from a tsunami typically drains pretty quickly, but there is a pond area in Mike Miller Park where the seawater likely settled and remained for a longer period of time," Dziak said.

Black added that the researchers' next step is to conduct an isotopic analysis on the wood from 1700.

"We will look for signatures consistent with those found in trees that were inundated by the 2011 Tohoku tsunami in Japan," he said. "If successful, we could develop a powerful new technique to map prehistoric tsunami run-up along the Pacific Northwest coast."Was Cascadia's 1700 earthquake part of a sequence of earthquakes?

More information: Robert P. Dziak et al, Assessing local impacts of the 1700 CE Cascadia earthquake and tsunami using tree-ring growth histories: a case study in South Beach, Oregon, USA, Natural Hazards and Earth System Sciences (2021). DOI: 10.5194/nhess-21-1971-2021

Provided by Oregon State University 

Tree rings from old growth Douglas-firs on the Oregon Coast show evidence of 1700 tsunami

Peer-Reviewed Publication

OREGON STATE UNIVERSITY

 

IMAGE: A STAND OF OLD GROWTH DOUGLAS-FIRS NEAR A POND IN MIKE MILLER PARK IN SOUTH BEACH, OREGON. view more 

CREDIT: BOB DZIAK.

NEWPORT, Ore. – Core samples taken from a stand of old growth Douglas-fir trees in the South Beach area just south of Newport showed reduced growth following the 9.0 earthquake and subsequent tsunami that struck the Pacific Northwest in 1700.

The physical evidence from the Douglas-fir tree rings confirms modeling that depicts the reach of the January 1700 quake, which was the last major earthquake to hit the Cascadia Subduction Zone, said Robert Dziak, a Hatfield Marine Science Center-based scientist with the National Oceanic and Atmospheric Administration Pacific Marine Environmental Laboratory.

“The tsunami appears to be the event that most affected the trees’ growth that year,” said Dziak, whose work includes ocean acoustic studies, signal analysis and tsunami modeling. He also holds a courtesy appointment in Oregon State University’s College of Earth, Ocean, and Atmospheric Sciences. “Getting these little bits of the picture helps us understand what we might expect when the next ‘big one’ hits.”

The findings were published recently in the journal Natural Hazards and Earth System Sciences.

The idea for the study dates back more than a decade; Dziak was aware of past research that had shown evidence of the 1700 quake in trees in Washington, and thought it might be worth seeing if similar evidence existed in Oregon.

The first challenge was finding a stand of old growth Douglas-firs in the tsunami inundation zone. The researchers looked at a few places before locating the stand in Mike Miller Park in South Beach, about two kilometers south of Yaquina Bay and 1.2 kilometers east of the present-day ocean shoreline.

“We’re not sure why this tree stand wasn’t logged over the years, but we’re very fortunate to have a site so close to the coastline that has survived,” said coauthor Bryan Black of the Laboratory of Tree-Ring Research at the University of Arizona, Tucson.  

A new and updated tsunami model run by the researchers as part of the study shows that the area could have been inundated by up to 10 meters of water in the 1700 tsunami event, said Dziak.

Once the old growth stand was identified, the researchers collected core samples from about 38 trees using a process that allows them to analyze the tree rings without damaging the overall health of the trees. The majority of the trees dated to around 1670, with one dating to 1650, Dziak said.

They analyzed the growth rates in the rings and compared the growth rates to those of other old-growth Douglas-firs at sites not in the tsunami inundation zone. They found that in 1700 the trees in the tsunami inundation zone showed a significantly reduced growth rate.

Researchers are still working to figure out why the tsunami might have affected the trees’ growth since the trees are relatively far from the shoreline. They suspect it may be a combination of the ground shaking from the earthquake and the inundation of seawater.

“The salty seawater from a tsunami typically drains pretty quickly, but there is a pond area in Mike Miller Park where the seawater likely settled and remained for a longer period of time,” Dziak said.

Black added that the researchers’ next step is to conduct an isotopic analysis on the wood from 1700.

“We will look for signatures consistent with those found in trees that were inundated by the 2011 Tohoku tsunami in Japan,” he said. “If successful, we could develop a powerful new technique to map prehistoric tsunami run-up along the Pacific Northwest coast.”

Additional coauthors of the study are Yong Wei of the University of Washington Cooperative Institute for Climate, Ocean and Ecosystem Studies with NOAA/PMEL in Seattle; and Susan Merle of the Cooperative Institute for Marine Resource Studies at Hatfield Marine Science Center.

CAPTION

A stand of old growth Douglas-firs near a pond in Mark Miller Park in South Beach, Oregon.

CREDIT

Bob Dziak.

---

JOURNAL

Natural Hazards and Earth System Sciences

DOI

10.5194/nhess-21-1971-2021 

ARTICLE TITLE

Assessing local impacts of the 1700 CE Cascadia earthquake and tsunami using tree-ring growth histories: a case study in South Beach, Oregon, USA

ARTICLE PUBLICATION DATE

30-Jun-2021

 

Norwegian company developing 1,000-foot-tall offshore wind turbine farms that could power 80,000 homes each

By Nathaniel Bahadursingh

 

Aug 23, '21 

 

All images courtesy of Wind Catching Systems

A Norwegian company is developing a new technology for floating, offshore wind turbine farms. Unlike traditional wind farms, these are organized in stacked, square grids, standing nearly as tall as the Eiffel Tower. 

The grids would stand at 1,000 feet tall, composed of multiple smaller turbines in a staggered formation atop a floating platform anchored to the ocean floor. Founded in 2017, Wind Catching Systems, in collaboration with Aibel AS as the main contractor and holding companies Ferd AS and North Energy ASA, aims to commercialize this wind catching technology. 

The company claims that its grids will increase efficiency, reduce land use by 80%, and reduce production costs, allowing the system to be immediately competitive with other traditional grid prices. In addition, the team states that one wind catching unit will be able to generate five times the annual energy output of the world’s largest single turbines and could produce enough electricity for 80,000 European households. This increased efficiency is attributed to the height of the grids, which exposes the rotors to higher wind speeds. Its smaller rotors can also perform better in higher wind speeds, whereas larger turbines tend to pitch their blades to avoid damage. 

Five Wind Catching units can produce the same amount of electricity as 25 conventional turbines, all while taking up much less space.

Furthermore, due to their array of small turbines, the grid system eliminates the need for a massive single component, which makes them easier to manufacture, install, and maintain. As reported by Asia Times, once the wind catching unit is deployed, the installation and maintenance work can be mainly conducted on-site without the need for specialist cranes or vessels. The wind turbine grids will have a design life of 50 years, compared to the 30-year lifespan of conventional wind turbines. 

“Our goal is to enable offshore wind operators and developers to produce electricity at a cost that competes with other energy sources, without subsidies,” says Wing Catching Systems CEO Ole Heggheim. “Simply put, we will deliver floating offshore wind at the costs of bottom-fixed technology solutions, which provides great opportunities on a global basis for the Norwegian supplier industry.”

The company aims to make its floating offshore wind technology competitive by 2023, which “is at least ten years earlier than conventional floating offshore wind farms.” 

Investment Director at Ferd, Erik Bjørstad, states that the goal is to complete technical testing and verification during 2021 and to offer commercial development solutions in 2022. 

“Wind Catching will challenge today’s established technology suppliers with its groundbreaking and patented design,” says Investment Director at North Energy Rachid Bendriss. “With our technology, offshore wind operators and developers will achieve the productions costs that they hoped to reach in 2030-2035 in a shorter timeframe.”

Freaky Fanged Frog Discovered in the Philippines

By UNIVERSITY OF KANSAS AUGUST 21, 2021

Mindoro Fanged Frog

Genetic samples of the new frog, known scientifically as Limnonectes beloncioi (or commonly as the Mindoro Fanged Frog), were collected years ago by KU scientists working in the field on Mindoro Island in the central Philippines but weren’t analyzed until recently. Credit: Scott Travers

Researchers at the University of Kansas have described a new species of fanged frog discovered in the Philippines that’s nearly indistinguishable from a species on a neighboring island except for its unique mating call and key differences in its genome.

The KU-led team has just published its findings in the peer-reviewed journal Ichthyology & Herpetology.

“This is what we call a cryptic species because it was hiding in plain sight in front of biologists for many, many years,” said lead author Mark Herr, a doctoral student at the KU Biodiversity Institute and Natural History Museum and Department of Ecology & Evolutionary Biology. “Scientists for the last 100 years thought that these frogs were just the same species as frogs on a different island in the Philippines because they couldn’t tell them apart physically. We ran a bunch of analyses — and they do indeed look identical to the naked eye — however, they are genetically isolated. We also found differences in their mating calls. They sound quite different. So, it was a case of using acoustics to determine that the species was different, as well as the new genetic information.”

Genetic samples of the new frog, known scientifically as Limnonectes beloncioi (or commonly as the Mindoro Fanged Frog), were collected years ago by KU scientists working in the field on Mindoro Island in the central Philippines but weren’t analyzed until recently. Because of its nearly identical physical similarity to a fanged frog on the island of Palawan, called Acanth’s Fanged Frog, it was assumed to be the same species.

Giant Luzon Fanged Frog

The Giant Luzon fanged frog, Limnonectes macrocephalus (from Luzon Island), has fangs similar to the Mindoro Fanged Frog. Credit: Rafe Brown

“You can look at two different things, but to the human eye without intensive investigation they might seem the same,” Herr said. “So, we took a bunch of measurements of hundreds of these frogs — how long their digits were specifically, how wide the tip of their toe was, the length of one specific segment of their leg, the diameter of their eye — in order to compare populations statistically, even if we thought they look the same. We ran statistical analyses on body shape and size, including a principal component analysis which uses all the measurements at once to compare the frog morphology in multivariate space. After all that, just like the scientists before us, we found nothing to differentiate the frogs based on the shape of their bodies and their size.”

However, because the fanged frogs inhabit islands separated by miles and miles of ocean, the researchers had doubts they were the same species, in part because they had different-sounding calls. They decided to analyze the frogs’ genome and determined the Mindoro Fanged Frog qualified as its own distinct species.

“We ran genetic analyses of these frogs using some specific genetic markers, and we used a molecular clock model just to get a very basic estimate how long we thought that these frogs may have been separated from one another,” Herr said. “We found they’re related to each other, they are each other’s close relatives, but we found they’d been separate for two to six million years — it’s a really long time for these frogs. And it’s very interesting that they still look so similar but sound different.”

The KU graduate student specializes in studying the many species of fanged frog across Southeast Asia, where he’s carried out extensive fieldwork. He said the frogs’ fangs likely are used in combat for access to prime mating sites and to protect themselves from predators. The Mindoro Fanged Frog, a stream frog, is sometimes hunted by people for food.

But the frog’s characteristic call, different from Acanth’s Fanged Frog, proved difficult for researchers to record.

“They’re really wary of us when we’re out there with our sound recorders trying to get recordings of these frogs — that’s a really tough aspect, and we were lucky in this project that we had people over many years that were out there and had recorded both of these frogs on Palawan and Mindoro. So, we had recordings from both islands, and that’s kind of rare with this group of fanged frogs because people eat them. They call at night, but the second a flashlight or human voice wanders into the equation they’re just going to take off — because they know that they can be killed by people.”

Herr’s description of the Mindoro Fanged Frog continues a long tradition of KU field research into the herpetological biodiversity of the Philippines and Southeast Asia, according to his faculty adviser Rafe Brown, professor of ecology & evolutionary biology and curator-in-charge of the Herpetology Division of the Biodiversity Institute and Natural History Museum.

“Mark’s discovery reinforces a lesson we’ve learned over and over through the years — things we thought we knew, combined with new information, emerge to teach us something completely unexpected,” Brown said. “A century ago, KU professor Edward Taylor identified the Mindoro Island population as Acanth’s Fanged Frog, the same species as he had named, a few years before, from Palawan Island — an arrangement that made very little sense. Zoom forward a hundred years, and we find with new technology, genetic information and bioacoustic data that the two islands’ populations are actually very well-differentiated, as we would expect. But not morphologically; their physical characteristics have not diverged. This is a case in which the formation of species has not been accompanied by morphological differentiation — so called ‘cryptic speciation.’”

Reference: “A New, Morphologically Cryptic Species of Fanged Frog, Genus Limnonectes (Amphibia: Anura: Dicroglossidae), from Mindoro Island, Central Philippines” by Mark W. Herr, Johana Goyes Vallejos, Camila G. Meneses, Robin K. Abraham, Rayanna Otterholt, Cameron D. Siler, Edmund Leo B. Rico and Rafe M. Brown, 13 April 2021, Ichthyology & Herpetology.

DOI: 10.1643/h2020095

Herr’s co-authors on the new paper are Brown; KU graduate students Johana Goyes Vallejos and Robin Abraham; Camila Meneses of the University of the Philippines at Los Baños; Rayanna Otterholt of Haskell Indian Nations University; Cameron Siler of the University of Oklahoma; and Edmund Leo B. Rico of the Center for Conservation Innovations and College of Sciences De La Salle University-Dasmariñas, Philippines.

When Greenland was green: rapid global warming 55 million years ago shows us what the future may hold

                              Milo Barham, Author provided

August 23, 2021 

Frozen northeast Greenland seems an unlikely place to gain insight into our ever-warming world. Between 50 million and 60 million years ago, however, the region was a different place.

Back then Greenland had a subtropical climate befitting of its name. It was host to volcanic activity that restructured the land and ocean connections and drove rapid warming.

The abrupt global warming event 56 million years ago, known as the Paleocene-Eocene Thermal Maximum (PETM), is often used as a worrying analogue for our current climate crisis.

Our research, published today in Communications Earth and Environment, provides crucial details about the event — with a focus on Greenland’s role in it.

Read more: Volcanic emissions caused the warmest period in past 56m years – new study

Lessons from Earth’s past

About 56 million years ago, increased volcanic activity resulted in the eruption of huge volumes of molten rock, in a vast area surrounding what would eventually become Iceland. Underground, the magma essentially “cooked” sediments rich in organic material, converting the stored carbon into gas.

This led to trillions of tonnes of greenhouse gases being released into the atmosphere. It drove an increase in ocean acidity and a rise in global temperatures to the tune of 5-8℃.

The environmental and ecological consequences were immense. Mass extinctions and animal migrations took place over just a few thousand years. Fast-forward to the release of the latest Intergovernmental Panel on Climate Change report, and there has never been a greater need to understand Earth’s climate systems.

The geological record provides an opportunity to learn from past climate events that occurred on a timescale far longer than human lifespans or any written history.

Most importantly, it could forewarn us of the outcomes of Earth’s current climate upheaval which is unfolding much more rapidly.

Greenland’s exotic land

Northeast Greenland is the world’s largest national park, and one of the most remote and unexplored areas on the planet.

For our study, we set out to map the environmental evolution and geographic response to volcanic activity throughout the PETM event in northeast Greenland. Volcanic activity has been identified as the “smoking gun” for what drove the PETM warming.

Greenland also acted as a gatekeeper for the once-narrow seaway that connected the Arctic and Atlantic oceans (before movement of the tectonic plates opened the Atlantic more fully).

Greenland therefore played a significant role in regulating climate-critical ocean connections. These channels control the distribution of heat, dissolved gasses such as oxygen and carbon dioxide, nutrients and moisture in the atmosphere.

Midnight sunset in the pristine northeast Greenland wilderness. Milo Barham

Our international team of geologists carefully mapped sediments and lava flows onshore in northeast Greenland, and in rock cores extracted from the nearby sea bed.

We identified and dated various microscopic plant and plankton fossils, which provided detailed information about the environment they would have lived in. This was combined with findings gleaned from tracing the echoes of sound waves under the seabed.

By measuring how sound waves are reflected by buried sediment, we mapped the thickness and development of the geological layers. This revealed how the landscape, now partly covered by ocean, evolved over time.

With this, we carefully resurrected an image of northeast Greenland as it was between 47 and 63 million years ago.

A hotter, wetter planet

We discovered that around the time of the PETM, volcanic uplift turned deeper marine environments around northeast Greenland into shallow estuaries, rivers and vegetated swampy floodplains.

Some carbonised fossil leaf impressions in finely laminated sediment, retrieved from the Wollaston Forland peninsula in northeast Greenland. Jussi Hovikoski

Around 56 million years ago lava began erupting across the region, building volcanic rock piles hundreds of metres high. As successive lava flows emerged, the hot, wet climate of the time eventually caused the surface to break down into a red soil called laterite.

Dr Steven Andrews inspecting the boundary between successive lava flows in Wollaston Forland in northeast Greenland. The faint red band directly above the geologists head represents the eruption surface of a lava flow that was broken down into laterite by the hot wet climate. Milo Barham

Our data from northeast Greenland are consistent with broader Arctic greenhouse reconstructions of the time. Both paint a picture of lush, swampy woodlands inhabited by cold-blooded reptiles, primates and hippo-like beasts unlike anything you’d see in today’s cooler world.
Ocean gateways and land bridges

Our work also reconstructs seabed uplift, and the emergence of large areas of land from the ocean. This is important as it would have caused a severe obstruction of the seaway that separated Greenland and Norway.

Such blockages are bad news. We know from the geological record that if critical ocean circulation stops, it can lead to dangerously acidic and oxygen-starved oceans, as well as enhanced climate disturbance.

That said, when the flow of water between the Atlantic and Arctic was constricted because of emerging land during the PETM, there was more opportunity for plants and animals to move around. The continental connection allowed species to migrate into cooler climates and escape the effects of the warming

.

This schematic diagram of the Arctic 50 to 60 million years ago shows how volcanic uplift would have narrowed the seaway between Greenland and Norway, restricting ocean exchange and consequently boosting flora and fauna migration. modified from Ron Blakey (2021) - https://doi.org/10.4138/atlgeol.2021.002 and Jussi Hovikoski et al. (2021) - https://doi.org/10.1038/s43247-021-00249-w

Back to the future

Today’s environments have been largely broken up by human activity through agriculture and urbanisation, which gives species under environmental stress less opportunity to move elsewhere to survive any change.

And although we’re still some way from matching the overall volume of greenhouse gas emissions released during the PETM, today’s emission rates are rising almost ten times faster. Our ecosystems are already displaying signs of destabilisation.

Recent studies have warned of weakening ocean circulation, which may lead to climatic tipping points. Without urgent intervention, the unfolding climate and ecological crisis could prove to be a far greater burden than the world can bear.

Authors

Milo Barham
Senior Lecturer, Curtin University

Jussi Hovikoski
Senior scientist, Geological Survey of Denmark and Greenland

Michael B.W. Fyhn
Geological Survey of Denmark and Greenland
Disclosure statement

Milo Barham works is a Senior Lecturer at Curtin University. He has received funding from industry partners and state geoscience bodies. He is affiliated with the Timescales of Mineral Systems Group and The Institute of Geoscience Research at Curtin University.

Jussi Hovikoski works as a Senior Scientist at the Geological Survey of Denmark and Greenland. He has received funding from GEUS, Greenland authorities and industry.

Michael B.W. Fyhn works as Senior Scientist for the Geological Survey of Denmark and Greenland (GEUS). He receives funding from GEUS, Greenlandic Authorities and industry.
Partners



Curtin University provides funding as a member of The Conversation AU.

Rise and fall of water blisters offers glimpse beneath Greenland’s thick ice sheet

Peer-Reviewed Publication

PRINCETON UNIVERSITY

 

IMAGE: A STUDY LED BY PRINCETON UNIVERSITY RESEARCHERS FOUND THAT AS MELTWATER LAKES ON THE SURFACE OF GREENLAND’S ICE SHEET (PICTURED) RAPIDLY DRAIN, THEY CREATE WATER BLISTERS BETWEEN THE ICE AND THE BEDROCK THAT SCIENTISTS COULD USE TO UNDERSTAND THE HYDROLOGICAL NETWORK BELOW GREENLAND’S THICK INLAND ICE SHEET. THESE NETWORKS COULD AFFECT THE STABILITY OF THE ICE SHEET AS EARTH’S CLIMATE WARMS. view more 

CREDIT: IMAGE FROM GOOGLE EARTH

Water “blisters” trapped beneath the thick interior of Greenland’s ice sheet could provide critical insight into the hydrological network coursing deep below Earth’s second largest body of ice — and how it might be destabilized by climate change, according to a new study.

Each year, thousands of natural meltwater lakes form on the surface of the ice sheet’s high-elevation interior, where ice can be more than a half-mile thick. As these lakes drain, they form large water-filled cavities between the ice and the bedrock.

By combining field observations with mathematical models and laboratory experiments, Princeton University-led researchers discovered that these blisters push the surface of the ice upward, then cause it to gradually drop down as the water permeates into the subglacial drainage system, according to a report in the journal Nature Communications.

The team shows for the first time that the rise and fall of the ice sheet caused by rapid lake drainages can be used to estimate a property known as transmissivity, which characterizes the efficiency of the water networks that form between the ice and the bedrock. Lake drainage presents a new tool for gauging transmissivity beneath inland regions of the ice sheet, where transmissivity is otherwise difficult to measure, the researchers reported. They found that transmissivity can increase by as much as two orders of magnitude during Greenland’s summer melt season.

The findings could shed light on how climate change will affect Greenland’s vast frozen interior as the planet warms and surface melting increases, said first author Ching-Yao Lai, an assistant professor of geosciences and atmospheric and oceanic sciences at Princeton. Water from surface melting can act as a lubricant, she said, causing the glacier to slide more easily across the bedrock.

Existing research has shown that a major way for surface melting to impact the stability of the Greenland ice sheet is by meltwater lubricating the ice-sheet bed, Lai said. The majority of these studies, however, have focused on low-elevation areas where the ice sheet is thinner. Previous studies also have suggested that increased surface melt could accelerate the velocity of the high-elevation, interior ice sheet, but these findings are based on computational models, rather than observations, Lai said.

The paper in Nature Communications provides a rare, observation-based glimpse into the largely inaccessible water networks underlying Greenland’s high-elevation ice sheet. The study was supported by Princeton’s High Meadows Environmental Institute (HMEI) and the HMEI Carbon Mitigation Initiative.

“We know that as the climate warms in the future, the surface melt zone can expand and migrate to higher elevations than currently observed. A big question that remains to be answered, however, is how much transmissivity can increase further inland,” said Lai, who is an associated faculty member in HMEI.

“A potential impact is that the link between surface melt and subglacial water-network development could be activated not only at lower elevations, as currently observed, but also at higher elevations,” she said. “More observations of seasonal changes of subglacial transmissivity in response to surface melting would be needed to really understand what would happen when melt migrates to higher elevation regions.”

Co-authors of the paper from Princeton are HMEI associated faculty member Howard Stone, Princeton’s Donald R. Dixon ’69 and Elizabeth W. Dixon Professor of Mechanical and Aerospace Engineering and chair of mechanical and aerospace engineering, and Danielle Chase, a graduate student in Stone’s Complex Fluids Group.

The study co-authors also included Laura Stevens, an associate professor of climate and earth surface processes at the University of Oxford who has extensive experience studying lake drainages and ice dynamics. Stevens helped collect the field observations in Greenland with co-authors Mark Behn, an associate professor of earth and environmental sciences at Boston College, and Sarah Das, an associate scientist at Woods Hole Oceanographic Institution. Timothy Creyts from the Lamont-Doherty Earth Observatory at Columbia University also is a co-author on the study.

The researchers used GPS data and field observations of five lake-drainage events that occurred between 2006-12 to estimate drainage volume and to observe surface displacements caused by lake drainage and subsequent blister formation.

“We observed in the GPS data a wide range of ice-sheet uplift relaxation times following the five drainage events,” Stevens said. “We had an inkling that this spread in relaxation times might be indicative of some characteristic of the subglacial drainage system. Our understanding was significantly improved as this collaboration between researchers with expertise in observational, theoretical and experimental approaches catalyzed.”

Chase — who received a HMEI Walbridge Fund Graduate Award to study fluid-driven fracturing — then designed a series of experiments using a type of silicone that mimics the deformable ice overtop a porous material that represents the bedrock. She injected fluid between the deformable sheet and the porous substrate, observing the time it took for a blister to form and then drain into the porous substrate. Working with Stone and Lai, Chase also developed a mathematical model that explains the physics that govern the surface uplift and relaxation due to water blister formation. Her work is the topic of a paper recently accepted by the journal Physical Review Fluids.

“Experiments can be helpful because, in the lab, we can control and measure all the parameters in the system, which allowed us to test our model,” Chase said. “We also can choose ideal materials. The system is small enough to be held in one hand and the material is transparent, so we were able to directly observe the shape of the blister and the drainage into the porous substrate over time.”

The study is unique for using laboratory experiments to investigate natural processes such as blister formation that are difficult to analyze in the field where researchers cannot control the parameters.

“It is valuable to have laboratory models to better understand the mechanisms behind the complex shape changes that occur in nature,” Stone said. “Here, the laboratory experiments captured the main mechanical features observed in the field and helped us understand the relaxation of the ice sheet as water drains along the glacial bed.”

The paper, “Hydraulic transmissivity inferred from ice-sheet relaxation following Greenland supraglacial lake drainages,” was published in Nature Communications. The work was supported by Lamont Postdoctoral Fellowships from the Lamont-Doherty Earth Observatory; a National Science Foundation (NSF) Graduate Research Fellowship; the NSF Office of Polar Programs (OPP-1643970) and Cryospheric Sciences Program (OPP-1838410, ARC-1023364, ARC-0520077, and NNX10AI30G); NASA (NNX16AJ95G); the Vetlesen Foundation; the High Meadows Environmental Institute and the HMEI Carbon Mitigation Initiative at Princeton University; and the Princeton University Library Open Access Fund.

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JOURNAL

Nature Communications

DOI

10.1038/s41467-021-24186-6 

METHOD OF RESEARCH

Experimental study

ARTICLE TITLE

Hydraulic transmissivity inferred from ice-sheet relaxation following Greenland supraglacial lake drainages

ARTICLE PUBLICATION DATE

25-Jun-2021

VIDEO  

https://www.eurekalert.org/multimedia/797324

 

CAPTION

Meltwater-filled cavities push the surface of the ice sheet upward (left), then cause it to gradually drop down (right) as the water permeates the subglacial drainage system. This rise and fall can be used to estimate a property of the subglacial drainage system known as transmissivity.

CREDIT

Image by Ching-Yao Lai, Department of Geosciences

 

CAPTION

The study used GPS observations of surface uplift caused by lake drainage events. Above, meltwater lakes on the surface (left) empty through fractures in the ice sheet (right). Water from surface melting can act as a lubricant that loosens the ice sheet’s grip on the ground.

CREDIT

Photos from Sentinel-2 imagery

Nuclear storage plans for north of England stir up local opposition

Communities react with shock to news they are being considered as locations for underground facility

A banner protesting against a proposal to build a nuclear waste facility in

 the Lake District. Photograph: Alamy

Tommy Greene
Mon 23 Aug 2021 18.12 BST

The long-running battle to build an underground nuclear waste facility in the north of England has run into fresh problems, as communities reacted with shock to the news that they were being considered as locations.

The north-east port town of Hartlepool is one of the sites in the frame as a potential site for a geological disposal facility (GDF), while a former gas terminal point at Theddlethorpe, near the Lincolnshire coast, is another. Cumbria, where much of the waste is stored above ground, is also being considered.

Victoria Atkins, a government minister and the MP for Louth and Horncastle, said she was “stunned” by the prospect that her constituency could host a GDF, claiming that the Conservative-controlled Lincolnshire county council’s engagement with the government’s radioactive waste management group had been kept hidden from her.

The facility is intended to deal with the long-running problem of nuclear waste storage by providing a safe deposit for approximately 750,000 cubic metres of high-activity waste hundreds of metres underground in areas thought to have suitable geology to securely isolate the radioactive material. The waste would be solidified, packaged and placed into deep subterranean vaults. The vaults would then be backfilled and the surrounding network of tunnels and chambers sealed.

The UK would be following the example of Finland, where a geological repository for high-level spent nuclear fuel is under construction at Olkiluoto. A handful of other countries are considering similar schemes in an attempt to tackle the long-term dilemma of radioactive waste management.

Between 70% and 75% of the UK’s high-activity radioactive waste, which would be designated for the GDF, is stored at the Sellafield facility in west Cumbria. The sources of the waste include power generation, military, medical and civil uses.

Existing international treaties prohibit countries from exporting the waste overseas, leading some scientists to argue for underground burial that, they say, would require no further human intervention once storage is complete.

Politicians first started talking about a GDF in the 1980s. This latest attempt would need a public consultation plus varying levels of approval, and would mean that, at the earliest, waste could be deposited there in the 2040s. It would resolve the long-term dilemma of radioactive waste storage “for a generation”, according to Prof Geraldine Thomas, a molecular pathologist at Imperial College London who also sits on the government’s radioactive waste management committee (RWM).

“People sometimes think storage will mean a lot more waste is going to accrue from new nuclear activity. But, actually, new nuclear developments are producing less and less waste. And we’ve got so much legacy waste that we need to get on and do something about it soon.”

Alongside job creation and investment promises, financial incentives worth £1m and £2.5m are on offer for communities that sign up to the engagement process, which has already led to nominations for two Cumbrian boroughs. Drop-in sessions are being held across Copeland and Allerdale by area-specific working groups that would help deliver the GDF.

“We try to stress as best we can that engagement does not commit communities to anything and they can always pull out at a later stage,” said Steve Reece, head of siting at the RWM. “We see it more as the beginning of a long journey.”

However, the proposals have stirred up strong local feeling among both community leaders and residents, and accusations of secrecy have been levelled at councils and the RWM in recent weeks.

In north-east England, the political fallout generated by news of the GDF “early stage” discussions triggered the resignation of Hartlepool council’s deputy leader, Mike Young, on Tuesday evening.

“We are making huge strides in Hartlepool and across Teesside and Darlington,” the Tees Valley mayor, Ben Houchen, said following the decision. “And the last thing we need as we sell our region to the world is to be known as the dumping ground for the UK’s nuclear waste.”

Cumbria county council, which resisted the last efforts to site a GDF locally in 2013, has declined to take part in either of the two existing working groups, saying its involvement would give the process “a credibility it doesn’t deserve”.

There is already considerable opposition from local groups. “The vast majority of people here are horrified by the GDF,” said Jane Bright, a Mablethorpe resident and spokesperson for the Guardians of the East Coast campaign. “I should think it’s no more welcome elsewhere. But there’s a lot of pride in this area and we’ll fight this for as long as it takes.”

Marianne Birkby, a Cumbrian resident and founder of the Radiation-Free Lakeland group, said: “We’re seen as the line of least resistance here. In Cumbria, we’ve been there before with this. Now people are now trying to get their heads around it again, in the middle of a pandemic. This dump would essentially make us a sacrifice zone to the nuclear industry.”