Predicting landslides with light

Optical fiber sensors are used around the world to monitor the condition of difficult-to-access segments of infrastructure-such as the underbellies of bridges, the exterior walls of tunnels, the feet of dams, long pipelines and railways in remote rural areas.

Now, a team of researchers in Italy are expanding the reach of optical fiber sensors “to the hills” by embedding them in shallow trenches within slopes to detect and monitor both large landslides and slow slope movements. The team will present their research at The Optical Society’s (OSA) 98th Annual Meeting, Frontiers in Optics, being held Oct. 19-23 in Tucson, Arizona, USA.

As major disasters around the world this year have shown, landslides can be stark examples of nature at her most unforgiving. Within seconds, a major landslide can completely erase houses and structures that have stood for years, and the catastrophic toll they inflict on communities is felt not just in that destructive loss of property but in the devastating loss of life. The 1999 Vargus tragedy in Venezuela, for instance, killed tens of thousands of people and erased whole towns from the map without warning.

The motivation for an early warning technology, like the one the Italian team has devised, is to find a way to mitigate such losses -just as hurricane tracking can prompt coastal evacuations and save lives.

Predicting Landslides by Detecting Land Strains


Landslides are failures of a rock or soil mass, and are always preceded by various types of “pre-failure” strains-known technically as elastic, plastic and viscous volumetric and shear strains. While the magnitude of these pre-failure strains depends on the rock or soil involved-ranging from fractured rock debris and pyroclastic flows to fine-grained soils-they are measurable. This new technology can detect small shifts in soil slopes, and thus can detect the onset of landslides. Usually, electrical sensors have been used for monitoring landslides, but these sensors are easily damaged. Optical fiber sensors are more robust, economical and sensitive. This is where the new technology could make a difference.

“Distributed optical fiber sensors can act as a ‘nervous system’ of slopes by measuring the tensile strain of the soil they’re embedded within,” explained Professor Luigi Zeni, who is in the Department of Industrial & Information Engineering at the Second University of Naples.

Taking it a step further, Zeni and his colleagues worked out a way of combining several types of optical fiber sensors into a plastic tube that twists and moves under the forces of pre-failure strains. Researchers are then able to monitor the movement and bending of the optical fiber remotely to determine if a landslide is imminent.

The use of novel fiber optic sensors “allows us to overcome some limitations of traditional inclinometers, because fiber-based ones have no moving parts and can withstand larger soil deformations,” Zeni said. “These sensors can be used to cover very large areas-several square kilometers-and interrogated in a time-continuous way to pinpoint any critical zones.”

The findings clearly demonstrate the potential of distributed optical fiber sensors as an entirely new tool to monitor areas subject to landslide risk, Zeni said, and to develop early warning systems based on geo-indicators-early deformations-of slope failures.

Scientists warn time to stop drilling in the dark

In areas where shale-drilling/hydraulic fracturing is heavy, a dense web of roads, pipelines and well pads turn continuous forests and grasslands into fragmented islands. -  Simon Fraser University PAMR
In areas where shale-drilling/hydraulic fracturing is heavy, a dense web of roads, pipelines and well pads turn continuous forests and grasslands into fragmented islands. – Simon Fraser University PAMR

The co-authors of a new study, including two Simon Fraser University research associates, cite new reasons why scientists, industry representatives and policymakers must collaborate closely on minimizing damage to the natural world from shale gas development. Viorel Popescu and Maureen Ryan, David H. Smith Conservation Research Fellows in SFU’s Biological Sciences department, are among eight international co-authors of the newly published research in Frontiers in Ecology and the Environment.

Shale gas development is the extraction of natural gas from shale formations via deep injection of high-pressure aqueous chemicals to create fractures (i.e., hydraulic fracturing), which releases trapped gas. With shale gas production projected to increase exponentially internationally during the next 30 years, the scientists say their key findings are cause for significant concern and decisive mitigation measures.

“Our findings are highly relevant to British Columbians given the impetus for developing shale resources in northeastern B.C. and the massive LNG facilities and pipeline infrastructure under development throughout the province,” notes Popescu. The SFU Earth2Ocean Group member is also a research associate in the Centre for Environmental Research at the University of Bucharest in Romania.

Key study findings:

  • One of the greatest threats to animal and plant-life is the cumulative impact of rapid, widespread shale development, with each individual well contributing collectively to air, water, noise and light pollution.

    “Think about the landscape and its habitats as a canvas,” explains Popescu. “At first, the few well pads, roads and pipelines from shale development seem like tiny holes and cuts, and the canvas still holds. But if you look at a heavily developed landscape down the road, you see more holes and cuts than natural habitats. Forests or grasslands that were once continuous are now islands fragmented by a dense web of roads, pipelines and well pads. At what point does the canvas fall apart? And what are the ecological implications for wide-ranging, sensitive species such as caribou or grizzly bears?”

  • Determining the environmental impact of chemical contamination from spills, well-casing failure and other accidents associated with shale gas production must become a top priority.

    Shale-drilling operations for oil and natural gas have increased by more than 700 per cent in the United States since 2007 and Western Canada is undergoing a similar shale gas production boom. But the industry’s effects on nature and wildlife are not well understood. Accurate data on the release of fracturing chemicals into the environment needs to be gathered before understanding can improve.

  • The lack of accessible and reliable information on spills, wastewater disposal and fracturing fluids is greatly impeding improved understanding. This study identifies that only five of 24 American states with active shale gas reservoirs maintain public records of spills and accidents.

The authors reviewed chemical disclosure statements for 150 wells in three top-gas producing American states and found that, on average, two out of three wells were fractured with at least one undisclosed chemical. Some of the wells in the chemical disclosure registry were fractured with fluid containing 20 or more undisclosed chemicals.

The authors call this an arbitrary and inconsistent standard of chemical disclosure. This is particularly worrisome given the chemical makeup of fracturing fluid and wastewater, which can include carcinogens and radioactive substances, is often unknown.

“Past lessons from large scale resource extraction and energy development -large dams, intensive forestry, or biofuel plantations – have shown us that development that outpaces our understanding of ecological impacts can have dire unintended consequences,” notes Ryan. She is a research fellow in the University of Washington’s School of Environmental and Forest Sciences.

“It’s our responsibility to look forward. For example, here in Canada, moving natural gas from northeastern B.C. to the 16 proposed LNG plants would require hundreds of kilometers of new pipeline and road infrastructure, and large port terminals on top of the effects of drilling. We must not just consider the impact of these projects individually, but also try to evaluate the ecological impacts holistically.”

‘Fracking’ in the dark: Biological fallout of shale-gas production still largely unknown

Eight conservation biologists from various organizations and institutions, including Princeton University, found that shale-gas extraction in the United States has vastly outpaced scientists' understanding of the industry's environmental impact. With shale-gas production projected to surge during the next 30 years, determining and minimizing the industry's effects on nature and wildlife must become a top priority for scientists, industry and policymakers, the researchers said. The photo above shows extensive natural-gas operations at Jonah Field in Wyoming. -  Photo courtesy of EcoFlight.
Eight conservation biologists from various organizations and institutions, including Princeton University, found that shale-gas extraction in the United States has vastly outpaced scientists’ understanding of the industry’s environmental impact. With shale-gas production projected to surge during the next 30 years, determining and minimizing the industry’s effects on nature and wildlife must become a top priority for scientists, industry and policymakers, the researchers said. The photo above shows extensive natural-gas operations at Jonah Field in Wyoming. – Photo courtesy of EcoFlight.

In the United States, natural-gas production from shale rock has increased by more than 700 percent since 2007. Yet scientists still do not fully understand the industry’s effects on nature and wildlife, according to a report in the journal Frontiers in Ecology and the Environment.

As gas extraction continues to vastly outpace scientific examination, a team of eight conservation biologists from various organizations and institutions, including Princeton University, concluded that determining the environmental impact of gas-drilling sites – such as chemical contamination from spills, well-casing failures and other accidents – must be a top research priority.

With shale-gas production projected to surge during the next 30 years, the authors call on scientists, industry representatives and policymakers to cooperate on determining – and minimizing – the damage inflicted on the natural world by gas operations such as hydraulic fracturing, or “fracking.” A major environmental concern, hydraulic fracturing releases natural gas from shale by breaking the rock up with a high-pressure blend of water, sand and other chemicals, which can include carcinogens and radioactive substances.

“We can’t let shale development outpace our understanding of its environmental impacts,” said co-author Morgan Tingley, a postdoctoral research associate in the Program in Science, Technology and Environmental Policy in Princeton’s Woodrow Wilson School of Public and International Affairs.

“The past has taught us that environmental impacts of large-scale development and resource extraction, whether coal plants, large dams or biofuel monocultures, are more than the sum of their parts,” Tingley said.

The researchers found that there are significant “knowledge gaps” when it comes to direct and quantifiable evidence of how the natural world responds to shale-gas operations. A major impediment to research has been the lack of accessible and reliable information on spills, wastewater disposal and the composition of fracturing fluids. Of the 24 American states with active shale-gas reservoirs, only five – Pennsylvania, Colorado, New Mexico, Wyoming and Texas – maintain public records of spills and accidents, the researchers report.

“The Pennsylvania Department of Environmental Protection’s website is one of the best sources of publicly available information on shale-gas spills and accidents in the nation. Even so, gas companies failed to report more than one-third of spills in the last year,” said first author Sara Souther, a postdoctoral research associate at the University of Wisconsin-Madison.

“How many more unreported spills occurred, but were not detected during well inspections?” Souther asked. “We need accurate data on the release of fracturing chemicals into the environment before we can understand impacts to plants and animals.”

One of the greatest threats to animal and plant life identified in the study is the impact of rapid and widespread shale development, which has disproportionately affected rural and natural areas. A single gas well results in the clearance of 3.7 to 7.6 acres (1.5 to 3.1 hectares) of vegetation, and each well contributes to a collective mass of air, water, noise and light pollution that has or can interfere with wild animal health, habitats and reproduction, the researchers report.

“If you look down on a heavily ‘fracked’ landscape, you see a web of well pads, access roads and pipelines that create islands out of what was, in some cases, contiguous habitat,” Souther said. “What are the combined effects of numerous wells and their supporting infrastructure on wide-ranging or sensitive species, like the pronghorn antelope or the hellbender salamander?”

The chemical makeup of fracturing fluid and wastewater is often unknown. The authors reviewed chemical-disclosure statements for 150 wells in three of the top gas-producing states and found that an average of two out of every three wells were fractured with at least one undisclosed chemical. The exact effect of fracturing fluid on natural water systems as well as drinking water supplies remains unclear even though improper wastewater disposal and pollution-prevention measures are among the top state-recorded violations at drilling sites, the researchers found.

“Some of the wells in the chemical disclosure registry were fractured with fluid containing 20 or more undisclosed chemicals,” said senior author Kimberly Terrell, a researcher at the Smithsonian Conservation Biology Institute. “This is an arbitrary and inconsistent standard of chemical disclosure.”

Liquefaction of seabed no longer a mystery

<IMG SRC="/Images/483586609.jpg" WIDTH="350" HEIGHT="222" BORDER="0" ALT="This is a pipeline floatation accident. Taken from the paper by J.S. Damgaard, B.M. Sumer, T.C. Teh, A.C. Palmer, P. Foray and D. Osorio: 'Guidelines for pipeline on-bottom stability on liquefied noncohesive seabeds' Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, vol. 132, No. 4, pp. 300-309, 2006. With permission from ASCE. – Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, vol. 132, No. 4, pp. 300-309, 2006. With permission from ASCE.”>
This is a pipeline floatation accident. Taken from the paper by J.S. Damgaard, B.M. Sumer, T.C. Teh, A.C. Palmer, P. Foray and D. Osorio: ‘Guidelines for pipeline on-bottom stability on liquefied noncohesive seabeds’ Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, vol. 132, No. 4, pp. 300-309, 2006. With permission from ASCE. – Journal of Waterway, Port, Coastal and Ocean Engineering, ASCE, vol. 132, No. 4, pp. 300-309, 2006. With permission from ASCE.

Seabed under large waves during storms may undergo liquefaction, a process in which the seabed sediment becomes liquid. Under this condition, sections of buried pipelines float to the surface of the seabed, heavy marine objects on the seabed such as breakwaters, caissons, sea mines, and pipelines sink and disappear into the seabed. How can this be explained?

Authored by renowned researcher and engineer Dr Mutlu Sumer and published by World Scientific, “Liquefaction Around Marine Structures”, features physics of liquefaction induced by large waves, mathematical modelling, floatation and sinking of marine objects in liquefied sediments. Although the main focus is the wave-induced liquefaction, it also discusses the seabed liquefaction caused by earthquakes. The book also addresses the issue of design of structures (against liquefaction) wherever it deems necessary, and provides guidelines via illustrated examples. Counter measures against seabed liquefaction is also discussed.

Many incidents with catastrophic consequences have occurred in the past due to wave-induced liquefaction of the seabed. There are also failures for which information never entered the public domain. Cost of such incidents is enormous, up to tens or even hundreds of million dollars.

The main cause of such incidents has been the fact that the structures (be it, for example, marine pipelines, or breakwaters, or caisson structures, or sea mines) have not been properly designed against liquefaction, and that has been due to the lack of knowledge, and the non-existence of guidelines for the design.

The present book essentially bridges this gap, for the first time, by collecting the state-of-the-art knowledge and building content, essentially based on the recent research conducted in the past two decades including two European research programs Liquefaction Around Marine Structures (LIMAS) and Scour Around Coastal Structures (SCARCOST) where the author was the Program Leader. The present book and the existing body of literature on earthquake-induced liquefaction (with special reference to marine structures) form a complementary source of information on liquefaction around marine structures, and will be used by consulting firms in the design of structures to ensure that incidents that occurred in the past with catastrophic dimensions can be avoided.

Dr. Mutlu Sumer is a Professor at the Technical University of Denmark, DTU Mekanik, Section for Fluid Mechanics, Coastal and Maritime Engineering. He has published two previous books with World Scientific, “Hydrodynamics Around Cylindrical Structures” and “The Mechanics of Scour in the Marine Environment”.

Nearby Georgia basin may amplify ground shaking from next quake

Tall buildings, bridges and other long-period structures in Greater Vancouver may experience greater shaking from large (M 6.8 +) earthquakes than previously thought due to the amplification of surface waves passing through the Georgia basin, according to two studies published by the Bulletin of the Seismological Society of America (BSSA). The basin will have the greatest impact on ground motion passing over it from earthquakes generated south and southwest of Vancouver.

“For very stiff soils, current building codes don’t include amplification of ground motion,” said lead author Sheri Molnar, a researcher at the University of British Columbia. “While the building codes say there should not be any increase or decrease in ground motion, our results show that there could be an average amplification of up to a factor of three or four in Greater Vancouver.”

The research provides the first detailed studies of 3D earthquake ground motion for a sedimentary basin in Canada. Since no large crustal earthquakes have occurred in the area since the installation of a local seismic network, these studies offer refined predictions of ground motion from large crustal earthquakes likely to occur.

Southwestern British Columbia is situated above the seismically active Cascadia subduction zone. A complex tectonic region, earthquakes occur in three zones: the thrust fault interface between the Juan de Fuca plate, which is sliding beneath the North America plate; within the over-riding North America plate; and within the subducting Juan de Fuca plate.

Molnar and her colleagues investigate the effect the three dimensional (3D) deep basin beneath Greater Vancouver has on the earthquake-generated waves that pass through it. The Georgia basin is one in a series of basins spanning form California to southern Alaska along the Pacific margin of the North America and is relatively wide and shallow. The basin is filled with sedimentary layers of silts, sands and glacial deposits.

While previous research suggested how approximately 100 meters of material near the surface would affect ground shaking, no studies had looked at the effect of the 3D basin structure on long period seismic waves.

To fill in that gap in knowledge, Molnar and colleagues performed numerical modeling of wave propagation, using various scenarios for both shallow quakes (5 km in depth) within the North America plate and deep quakes (40 – 55 km in depth) within the Juan de Fuca subducting plate, the latter being the most common type of earthquake. The authors did not focus on earthquakes generated by a megathrust rupture of the Cascadia subduction zone, a scenario studied previously by co-author Kim Olsen of San Diego State University.

For these two studies, the authors modeled 10 scenario earthquakes for the subducting plate and 8 shallow crustal earthquakes within the North America plate, assuming rupture sites based on known seismicity. The computational analyses suggest the basin distorts the seismic radiation pattern – how the energy moves through the basin – and produces a larger area of higher ground motions. Steep basin edges excite the seismic waves, amplifying the ground motion.

The largest surface waves generated across Greater Vancouver are associated with earthquakes located approximately 80 km or more, south-southwest of the city, suggest the authors.

“The results were an eye opener,” said Molnar. “Because of the 3D basin structure, there’s greater hazard since it will amplify ground shaking. Now we have a grasp of how much the basin increases ground shaking for the most likely future large earthquakes.”

In Greater Vancouver, there are more than 700 12-story and taller commercial and residential buildings, and large structures – high-rise buildings, bridges and pipelines – that are more affected by long period seismic waves, or long wavelength shaking. “That’s where these results have impact,” said Molnar.

The greatest story of man and permafrost





Alyeska Pipeline Service Company Engineer Elden Johnson provides a lecture underneath a portion of the trans-Alaska oil pipeline. - Photo by Ned Rozell
Alyeska Pipeline Service Company Engineer Elden Johnson provides a lecture underneath a portion of the trans-Alaska oil pipeline. – Photo by Ned Rozell

In 1973, Elden Johnson was a young engineer working on one of the most ambitious and uncertain projects in the world–an 800-mile steel pipeline that carried warm oil over frozen ground. Thirty-five years later, Johnson looked back at what he called “the greatest story ever told of man’s interaction with permafrost.”



Strung over and beneath the surface of Alaska from Prudhoe Bay to Valdez, the trans-Alaska pipeline, at 31 years old, is entering its second lifetime. The four-foot in diameter, half-inch-thick steel pipe had an original design lifespan of 30 years. The State of Alaska and the U.S. Department of the Interior recently gave the pipeline the green light for another 30 years of operation.



“It’s like a car,” said Johnson, who works for Alyeska Pipeline Service Company, while standing under the pipeline near Fairbanks during a recent permafrost conference lecture. “As long as you maintain it, it’ll continue to work.”



Permafrost, frozen ground that is a relic of the last ice age, exists beneath about 75 percent of the pipeline’s 800-mile route. When ice-rich permafrost thaws, the ground slumps, causing problems for structures above.



After the 1969 oil discovery at Prudhoe Bay, developers unfamiliar with Alaska wanted to bury the entire supply of Japanese-made pipe. After a review by people who knew the dangers of building on permafrost, a legion of workers constructed a pipeline buried for 380 miles and–in areas of permafrost–built above the ground on platforms for 420 miles.



The initial design was good, but not perfect, Johnson said. He remembered during construction when he and others were inspecting the ground from the Yukon River to Coldfoot. They found unstable permafrost and recommended re-design of sections of the pipeline. Instead of conventional buried pipeline, the engineers called for more expensive and time-consumptive, above-ground pipeline.


“We changed the design for at least 20 percent of that distance,” he said. “They were gut-wrenching decisions potentially impacting the startup schedule.”



The call to elevate more than half the pipeline turned out to be a good one. Even though engineers bored holes in the ground about every 800 feet to check for permafrost, they didn’t find it all. When the pipeline was two years old in 1979, the pipe buckled and leaked in two buried sections because of thawed permafrost. In both cases, the pipeline, which carried oil that left the ground in Prudhoe Bay as warm as 145 degrees Fahrenheit, caused about four feet of settlement. Engineers fixed those and other problems. The two leaks in 1979 are still the only spills caused by permafrost.



Alyeska workers check the pipeline each year for signs of settling and proper operation of the heat pipes that help keep the support posts of the above-ground pipeline anchored in frozen ground. The buried pipeline has become more stable over its 31 years as the rapid thawing of early years has settled down.



“The risk to the buried pipeline right now is becoming minimal,” Johnson said.



The pipeline has delivered more than 16 billion barrels of oil since its startup in June 1977, with two brief shutdowns due to permafrost. Johnson estimated permafrost-related maintenance has totaled about 5-to-10 percent of the operating costs over the life of the pipeline.



“It’s the cost of doing business in the Arctic,” he said



With a career of work on the massive engineering project Johnson calls “a beautiful thing,” he is retiring from Alyeska this winter. His mind won’t stray far from the challenges of building pipelines across cold country. His daughter Katie, a mechanical engineering graduate from the University of Alaska Fairbanks, has just signed on to help work with the natural gas pipeline from the North Slope southward.



“It’s kind of a second-generation opportunity to look at the next pipeline,” Johnson said.