Calculating tsunami risk for the US East Coast

The greatest threat of a tsunami for the U.S. east coast from a nearby offshore earthquake stretches from the coast of New England to New Jersey, according to John Ebel of Boston College, who presented his findings today at the Seismological Society of America 2013 Annual Meeting.

The potential for an East Coast tsunami has come under greater scrutiny after a 2012 earthquake swarm that occurred offshore about 280 kilometers (170 miles) east of Boston. The largest earthquake in the 15-earthquake swarm, most of which occurred on April 12, 2012, was magnitude (M) 4.0.

In 2012 several other earthquakes were detected on the edge of the Atlantic continental shelf of North America, with magnitudes between 2 and 3.5. These quakes occurred off the coast of southern Newfoundland and south of Cape Cod, as well as in the area of the April swarm. All of these areas have experienced other earthquake activity in the past few decades prior to 2012.

The setting for these earthquakes, at the edge of the continental shelf, is similar to that of the 1929 M7.3 Grand Banks earthquake, which triggered a 10-meter tsunami along southern Newfoundland and left tens of thousands of residents homeless.

Ebel’s preliminary findings suggest the possibility than an earthquake-triggered tsunami could affect the northeast coast of the U.S. The evidence he cites is the similarity in tectonic settings of the U.S. offshore earthquakes and the major Canadian earthquake in 1929. More research is necessary, says Ebel, to develop a more refined hazard assessment of the probability of a strong offshore earthquake along the northeastern U.S. coast.

Measuring the hazards of global aftershock

The entire world becomes an aftershock zone after a massive magnitude (M) 7 or larger earthquake-but what hazard does this pose around the planet? Researchers are working to extend their earthquake risk estimates over a global scale, as they become better at forecasting the impact of aftershocks at a local and regional level.

There is little doubt that surface waves from a large, M≥7 earthquake can distort fault zones and volcanic centers as they pass through the Earth’s crust, and these waves could trigger seismic activity. According to the Tom Parsons, seismologist with the U.S. Geological Survey, global surveys suggest that there is a significant rate increase in global seismic activity during and in the 45 minutes after a M≥7 quake across all kinds of geologic settings. But it is difficult to find strong evidence that surface waves from these events immediately trigger M>5 earthquakes, and these events may be relatively rare. Nevertheless, seismologists would like to be able to predict the frequency of large triggered quakes in this global aftershock zone and associated hazard.

Studies of hundreds of M≥7 mainshock earthquake effects in 21 different regions around the world has provided some initial insights into how likely a damaging global aftershock might be. Initial results show that remote triggering has occurred at least once in about half of the regions studied during the past 30 years. Larger (M>5) global aftershocks appear to be delayed by several hours as compared with their lower magnitude counterparts. Parsons suggests that local seismic networks can monitor the rate of seismic activity immediately after a global mainshock quake, with the idea that a vigorous uptick in activity could signal a possible large aftershock.

Parsons presented his research at the annual meeting of the Seismological Society of America, which is an international scientific society devoted to the advancement of seismology and the understanding of earthquakes for the benefit of society. It publishes the prestigious peer-reviewed journal BSSA – the Bulletin of the Seismological Society of America – and the bimonthly Seismological Research Letters, which serves as a general forum for informal communication among seismologists and those interested in seismology and related disciplines.

Geochemical method finds links between terrestrial climate and atmospheric carbon dioxide

<IMG SRC="/Images/583714783.jpg" WIDTH="350" HEIGHT="237" BORDER="0" ALT="Michael Hren of the University of Connecticut and his coauthors examined these carbonate shells of the freshwater gastropod Viviparus lentus from the Hampshire Basin, United Kingdom. They used a clumped-isotope thermometer technique to determine the concentration of bonded heavy oxygen and carbon isotopes in these shells, which gives a picture of land temperatures during the Eocence-Oligocene transition, about 34 million years ago. Terrestrial temperatures were determined to be closely linked to atmospheric carbon dioxide. – Photo courtesy Michael Hren.”>
Michael Hren of the University of Connecticut and his coauthors examined these carbonate shells of the freshwater gastropod Viviparus lentus from the Hampshire Basin, United Kingdom. They used a clumped-isotope thermometer technique to determine the concentration of bonded heavy oxygen and carbon isotopes in these shells, which gives a picture of land temperatures during the Eocence-Oligocene transition, about 34 million years ago. Terrestrial temperatures were determined to be closely linked to atmospheric carbon dioxide. – Photo courtesy Michael Hren.

Nearly thirty-four million years ago, the Earth underwent a transformation from a warm and high-carbon dioxide “greenhouse” state to a lower-CO2, variable climate of the modern “icehouse” world. Massive ice sheets grew across the Antarctic continent, major animal groups shifted, and ocean temperatures decreased by up to 5 degrees.

But studies of how this drastic change affected temperatures on land have had mixed results. Some show no appreciable terrestrial climate change; others find cooling of up to 8 degrees and large changes in seasonality.

Now, a group of American and British scientists have used a new chemical technique to measure the change in terrestrial temperature associated with this shift in global atmospheric CO2 concentrations.

Their results suggest a drop of as much as 10 degrees for fresh water during the warm season and 6 degrees for the atmosphere in the North Atlantic, giving further evidence that the concentration of atmospheric carbon dioxide and Earth’s surface temperature are inextricably linked.

“One of the key principles of geology is that the past is the key to the present: records of past climate inform us of how the Earth system functions,” says Michael Hren, Assistant Professor of Chemistry and Geosciences at the University of Connecticut and the study’s lead author. “By understanding past climate transitions, we can better understand the present and predict impacts for the future.”

The transition between the Late Eocene and the Oligocene epochs (between 34-33.5 million years ago) was triggered in part, the authors write in their April 22 paper in Proceedings of the National Academy of Sciences, by changes in the concentration of atmospheric CO2 that enabled ice to build up on the Antarctic continent.

Ice-sheet growth, coupled with favorable changes in the Earth’s orbit, pushed the planet past a climatic tipping point and led to both the rapid buildup of a permanent ice sheet in the Antarctic and much larger changes in global climate, says Hren.

But much of what is known about this time period’s climate comes from cores drilled deep in the ocean, Hren says. There, organic and inorganic remains of ancient marine creatures retain chemical signatures of ocean temperatures when they were alive.

Now, Hren and his colleagues have used a recently developed “clumped isotope thermometer” to examine terrestrial fossil shells from this time period. The team collected fossilized snails from the Isle of Wight, Great Britain, and looked for not just the kind and number of carbon and oxygen isotopes present, but how they were bound together.

The abundance of bonds containing heavy isotopes of both oxygen and carbon are temperature-dependent, so they can give a reliable picture of the terrestrial climate.

“The unique thing here is that we’re using isotopologues to measure the temperature that these snails experienced, and relating that to the climate during this interval of declining CO2,” Hren says.

What makes their results so important, says Hren, is that it’s further evidence that CO2 is linked not only to climate by way of the vast oceans and their temperature, but by terrestrial temperatures, too.

“It gives further evidence of the close links between atmospheric CO2 and temperature, but also shows how heterogeneous this climate change may be on land,” he adds.

Studies have shown that before this drastic cooling event, Earth’s atmosphere contained 1000 parts per million (ppm) of CO2 or more, and by the end of the transition, it was likely lower than 600-700 ppm. Some predictions, notes Hren, suggest that Earth’s current CO2 concentrations, currently at close to 400 ppm and climbing, could increase to nearly 1000 ppm in the next 100 years.

If that turns out to be the case, it’s likely that temperature changes on the scale of the Eocene to Oligocene could occur – but in the other direction, toward a much warmer climate that could again fundamentally alter the living things on Earth.

“We are on a path to fundamentally alter our global climate state,” says Hren. “These data definitely give you pause.”

Snail tale: Fossil shells and new geochemical technique provide clues to ancient climate cooling

Using a new laboratory technique to analyze fossil snail shells, scientists have gained insights into an abrupt climate shift that transformed the planet nearly 34 million years ago.

At that time, the Earth switched from a warm and high-carbon dioxide “greenhouse” state to the lower-carbon dioxide, variable climate of the modern “icehouse” world. Massive ice sheets grew across the Antarctic continent, major animal groups shifted and ocean temperatures decreased by up to 5 degrees Celsius (9 degrees Fahrenheit).

But studies of how this drastic change affected temperatures on land have had mixed results. Some show no appreciable terrestrial climate change; others find cooling of up to 8 C (14.4 F) and large changes in seasonality.

Now, a group of American and British scientists – including two from the University of Michigan – has used a new geochemical technique to analyze heavy isotopes of carbon and oxygen in fossil snail shells. They used the method to measure the change in land temperature associated with this shift in global atmospheric carbon dioxide concentrations.

Their results suggest a drop of as much as 10 C (18 F) for freshwater during the warm season and 6 C (10.8 F) for the atmosphere in the North Atlantic, giving further evidence that the concentration of atmospheric carbon dioxide and Earth’s surface temperature are inextricably linked.

The team’s findings will be published online April 22 in the Proceedings of the National Academy of Sciences. The lead author of the paper is Michael Hren, assistant professor of chemistry and geosciences at the University of Connecticut. The U-M co-authors are Nathan Sheldon and Kyger Lohmann of the Department of Earth and Environmental Sciences.

“One of the key principles of geology is that the past is the key to the present: records of past climate inform us of how the Earth system functions. By understanding past climate transitions, we can better understand the present and predict impacts for the future,” said Hren, a former U-M postdoctoral researcher who worked under Sheldon.

“While our understanding of past changes in the temperature of Earth’s oceans is well established, deciphering the environmental conditions of terrestrial settings has remained elusive. With the application of new analytical techniques, it is now possible to illuminate the paired response of the ocean-land system during episodes of global climate change,” said Lohmann, the director of the Stable Isotope Laboratory, the first U-M facility to use the “clumped-isotope technique.”

The transition between the late Eocene and the Oligocene epochs (between 34 and 33.5 million years ago) was triggered in part by changes in the concentration of atmospheric carbon dioxide that enabled ice to build up on the Antarctic continent.

Ice-sheet growth, coupled with favorable changes in the Earth’s orbit, pushed the planet past a climatic tipping point and led to both the rapid buildup of a permanent ice sheet in the Antarctic and much larger changes in global climate, the authors wrote.

But much of what is known about this time period’s climate comes from cores drilled deep in the ocean. There, organic and inorganic remains of ancient marine creatures retain chemical signatures of ocean temperatures when they were alive.

Now, the U-M researchers and their colleagues have used the recently developed “clumped-isotope thermometer” technique to examine terrestrial fossil shells from this time period. The team collected fossilized snails from the Isle of Wight, Great Britain, and looked for not just the kind and number of carbon and oxygen isotopes present, but how they were bound together.

The abundance of bonds containing heavy isotopes of both oxygen and carbon are temperature-dependent, so they can give a reliable picture of the climate of terrestrial environments.

“The application of the clumped-isotope technique provides a unique record of temperature change on land where earlier estimates based on other proxies were either imprecise or ambiguous,” Lohmann said. “This illuminates the response of the terrestrial climate system during this interval of declining carbon dioxide.”

The results are significant in part because they provide further evidence that carbon dioxide is linked to climate not only by way of the vast oceans and their temperature, but by terrestrial temperatures, too, Hren said.

Studies have shown that before this drastic cooling event, Earth’s atmosphere contained 1,000 parts per million of carbon dioxide or more. By the end of the transition, it was likely lower than 600-700 ppm. Some predictions, noted Hren, suggest that Earth’s current carbon dioxide concentrations, close to 400 ppm and climbing, could increase to nearly 1,000 ppm in the next 100 years.

If that turns out to be the case, it’s likely that temperature changes on the scale of the Eocene to Oligocene could occur – but in the other direction, toward a much warmer climate that could again fundamentally alter life on Earth.

“The terrestrial setting is the habitat of humanity,” Lohmann said. “Therefore, understanding the magnitude and heterogeneity of temperature change on land is essential if we are to model and predict the future impacts on society as our climate warms.”

The future of power?

South Dakota School of Mines & Technology researchers have successfully split water molecules during multiple thermochemical cycles at low temperatures, sparking hope that sustainable hydrogen energy will one day be feasible.

Rajesh Shende, Ph.D., and Jan Puszynski, Ph.D., of the Department of Chemical and Biological Engineering, have been awarded a $299,975 National Science Foundation (NSF) three-year grant to investigate a high-temperature thermochemical water splitting process. The ultimate goal is to exponentially double hydrogen atoms, creating a sustainable amount of hydrogen regeneration so that a new form of energy can be harvested.

Using thermally-stabilized redox materials, particularly ferrites, the SDSM&T team has documented reliable multiple-cycle results, says Shende.

Just two other U.S. locations, and possibly a third, are conducting similar research, according to Shende. One of the aspects that makes the South Dakota School of Mines & Technology experiments unique is that the group has successfully split water molecules during multiple cycles at significantly lower temperatures than other documented research efforts. While others have demonstrated thermochemical splitting of the water molecule at 800-1,500 degrees Celsius, the SD School of Mines & Technology has documented higher hydrogen volume from water-splitting in multiple cycles at 700-1,100 degrees Celsius, which could potentially lead to a more affordable large-scale effort.

In addition, the School of Mines process is capable of performing water-splitting and material regeneration steps at the same temperature making the process thermally efficient. “In industry this will be more appealing,” says Shende, who is filing an invention disclosure and who has published his findings in scientific magazines.

Higher temperatures normally cause particles to grow so large that hydrogen levels drop, causing very little hydrogen regeneration. The SDSM&T experimental studies look to stabilize the hydrogen levels, enhancing knowledge of the physical and chemical processes involved in thermal stabilization of redox materials’ morphologies without deterioration of complex ferrites. “Others might be splitting water by other methods, but there has to be a lot of novelty to get funded,” says Shende, who built a fully instrumented reactor in his campus laboratory.

Mine disaster: Hundreds of aftershocks

A study by University of Utah mining engineers and seismologists found 2,189 suspected seismic events before and after Utah's deadly Crandall Canyon coal mine collapse in 2007, and 1,328 of those events have a high probability of being real: 759 seismic events before the collapse (many related to mining) and 569 aftershocks (some related to rescue efforts). The high-probability events shown here reveal seismic activity clustered in three areas, two of which already were known: near the east end of the mine
(right) and where miners were working, toward the west end of the mine (left of center).  But the third cluster, at the mine's west end (far left) was revealed by the new study. It shows the collapse was at least as big and possibly larger than a 2008 University of Utah study that revealed the collapse extended from the east part of the mine to the area where miners were working. For comparison, see other map. -  Tex Kubacki, University of Utah.
A study by University of Utah mining engineers and seismologists found 2,189 suspected seismic events before and after Utah’s deadly Crandall Canyon coal mine collapse in 2007, and 1,328 of those events have a high probability of being real: 759 seismic events before the collapse (many related to mining) and 569 aftershocks (some related to rescue efforts). The high-probability events shown here reveal seismic activity clustered in three areas, two of which already were known: near the east end of the mine
(right) and where miners were working, toward the west end of the mine (left of center). But the third cluster, at the mine’s west end (far left) was revealed by the new study. It shows the collapse was at least as big and possibly larger than a 2008 University of Utah study that revealed the collapse extended from the east part of the mine to the area where miners were working. For comparison, see other map. – Tex Kubacki, University of Utah.

A new University of Utah study has identified hundreds of previously unrecognized small aftershocks that happened after Utah’s deadly Crandall Canyon mine collapse in 2007. The aftershocks suggest the collapse was as big – and perhaps bigger – than shown in another study by the university in 2008.

Mapping out the locations of the aftershocks “helps us better delineate the extent of the collapse at Crandall canyon. It’s gotten bigger,” says Tex Kubacki, a University of Utah master’s student in mining engineering.

“We can see now that, prior to the collapse, the seismicity was occurring where the mining was taking place, and that after the collapse, the seismicity migrated to both ends of the collapse zone,” including the mine’s west end, he adds.

Kubacki was scheduled to present the findings Friday in Salt Lake City during the Seismological Society of America’s 2013 annual meeting.

Six coal miners died in the Aug. 6, 2007 mine collapse, and three rescuers died 10 days later. The mine’s owner initially blamed the collapse on an earthquake, but the University of Utah Seismograph Stations said it was the collapse itself, not an earthquake, that registered on seismometers.

A 2008 study by University of Utah seismologist Jim Pechmann found the epicenter of the collapse was near where the miners were working, and aftershocks showed the collapse area covered 50 acres, four times larger than originally thought, extending from crosscut 120 on the east to crosscut 143 on the west, where miners worked. A crosscut is a north-south tunnel intersecting the mine’s main east-west tunnels.

In the new study, the collapse area “looks like it goes farther west – to the full extent of the western end of the mine, Kubacki says.

Study co-author Michael “Kim” McCarter, a University of Utah professor of mining engineering, says the findings are tentative, but “might extend the collapse farther west.” He is puzzled because “some of that is in an area where no mining had occurred.”

Kubacki says one theory is that the seismic events at the west end and some of those at the eastern end of the mine may be caused by “faulting forming along a cone of collapse” centered over the mine.

Kubacki and McCarter conducted the new study with seismologists Keith Koper and Kris Pankow of the University of Utah Seismograph Stations. McCarter and Pankow also coauthored the 2008 study.

Before the new study, researchers knew of about 55 seismic events – down to magnitude 1.6 – near the mine before and after the collapse, which measured 3.9 on the local magnitude scale and 4.1 on the “moment” magnitude scale that better reflects energy release, Kubacki says.

The new study analyzed records of seismometers closest to the mine for evidence of tremors down to magnitudes minus-1, which Kubacki says is about one-tenth the energy released by a hand grenade. He found:

  • Strong statistical evidence there were at least 759 seismic events before the mine collapse and 569 aftershocks.

  • Weak evidence there were as many as 1,022 seismic events before the collapse and 1,167 aftershocks.

“We’ve discovered up to about 2,000 previously unknown events spanning from July 26 to Aug. 30, 2007,” Kubacki says, although some of the weak-evidence events may turn out not to be real or to be unrelated to the collapse.

The seismic events found in the new study show tremors clustered in three areas: the east end of the collapse area, the area where miners were working toward the mine’s west end, and – new in this study – at the mine’s west end, beyond where miners worked.

“We have three clusters to look at and try to come up with an explanation of why there were three,” McCarter says. “They are all related to the collapse.”

Some of the tremors in the eastern cluster are related to rescue attempts and a second collapse that killed three rescuers, but some remain unexplained, he adds.

Kubacki says most of the seismic activity before the collapse was due to mining, although scientists want to investigate whether any of those small jolts might have been signs of the impending collapse. So far, however, “there is nothing measured that would have said, ‘Here’s an event [mine collapse] that’s ready to happen,” McCarter says.

Kubacki came up with the new numbers of seismic events by analyzing the records of seismometers closest to Crandall Canyon (about 12 miles away). “We took the known seismic events already in the catalog and searched for events that looked the same,” he adds. “These new events kept popping up. There are tiny events that may show up on one station but not network-wide.”

“Any understanding we can get toward learning how and why mine collapses happen is going to be of interest to the mining community,” Kubacki says.

McCarter adds: “We are looking at the Crandall Canyon event because we have accurate logs and very extensive seismic data, and that provides a way of investigating the data to see if anything could be applied to other mines to improve safety.”

Helping to forecast earthquakes in Salt Lake Valley

Salt Lake Valley, home to the Salt Lake City segment of the Wasatch fault zone and the West Valley fault zone, has been the site of repeated surface-faulting earthquakes (of about magnitude 6.5 to 7). New research trenches in the area are helping geologists and seismologists untangle how this complex fault system ruptures and will aid in forecasting future earthquakes in the area.

At the annual meeting of the Seismological Society of America (SSA), Christopher DuRoss and Michael Hylland of the Utah Geological Survey will present research today that indicates geologically recent large earthquakes on the West Valley fault zone likely occurred with (or were triggered by) fault movement on the Salt Lake City segment. DuRoss and Hylland consider it less likely that West Valley fault movement happens completely independently from movement on the Salt Lake City segment. This likely pairing has implications for how the seismic hazard in Salt Lake Valley is modeled.

The trenches have also helped the researchers revise the history of large earthquakes in the area, showing that the Salt Lake City segment has been more active than previously thought. Since about 14,000 years ago, eight quakes have occurred on the segment. Depending on the time period, these quakes have occurred roughly every 1300 to 1500 years on average. It has been 1400 years since the most recent large earthquake on the segment. The earthquake history of the West Valley fault zone had been largely unknown, but now four earthquakes have been well dated.

This new fault research contributes to a broader goal of evaluating Utah’s earthquake hazards and risk. For example, this type of information on prehistoric earthquakes will be used by the Working Group on Utah Earthquake Probabilities, formed under the auspices of the Utah Geological Survey and U.S. Geological Survey, to forecast probabilities for future earthquakes in the Wasatch Front region.

Research aims to settle debate over origin of Yellowstone volcano

A debate among scientists about the geologic formation of the supervolcano encompassing the region around Yellowstone National Park has taken a major step forward, thanks to new evidence provided by a team of international researchers led by University of Rhode Island Professor Christopher Kincaid.

In a publication appearing in last week’s edition of Nature Geoscience, the URI team demonstrated that both sides of the debate may be right.

Using a state-of-the-art plate tectonic laboratory model, they showed that volcanism in the Yellowstone area was caused by severely deformed and defunct pieces of a former mantle plume. They further concluded that the plume was affected by circulation currents driven by the movement of tectonic plates at the Cascades subduction zone.

Mantle plumes are hot buoyant upwellings of magma inside the Earth. Subduction zones are regions where dense oceanic tectonic plates dive beneath buoyant continental plates. The origins of the Yellowstone supervolcano have been argued for years, with sides disagreeing about the role of mantle plumes.

According to Kincaid, the simple view of mantle plumes is that they have a head and a tail, where the head rises to the surface, producing immense magma structures and the trailing tail interacts with the drifting surface plates to create a chain of smaller volcanoes of progressively younger age. But Yellowstone doesn’t fit this typical mold.Among its oddities, its eastward trail of smaller volcanoes called the Snake River Plain has a mirror-image volcanic chain, the High Lava Plain, that extends to the west.As a result, detractors say the two opposite trails of volcanoes and the curious north-south offset prove the plume model simply cannot work for this area, and that a plates-only model must be at work.

To examine these competing hypotheses, Kincaid, former graduate student Kelsey Druken, and colleagues at the Australian National University built a laboratory model of the Earth’s interior using corn syrup to simulate fluid-like motion of Earth’s mantle. The corn syrup has properties that allow researchers to examine complex time changing, three-dimensional motions caused by the collisions of tectonic plates at subduction zones and their effect on unsuspecting buoyant plumes.

By using the model to simulate a mantle plume in the Yellowstone region, the researchers found that it reproduced the characteristically odd patterns in volcanism that are recorded in the rocks of the Pacific Northwest.

“Our model shows that a simple view of mantle plumes is not appropriate when they rise near subduction zones, and that these features get ripped apart in a way that seems to match the patterns in magma output in the northwestern U.S. over the past 20 million years,” said Kincaid, a professor of geological oceanography at the URI Graduate School of Oceanography. “The sinking plate produces a flow field that dominates the interaction with the plume, making the plume passive in many ways and trapping much of the magma producing energy well below the surface. What you see at the surface doesn’t look like what you’d expect from the simple models.”

The next step in Kincaid’s research is to conduct a similar analysis of the geologic formations in the region around the Tonga subduction zone and the Samoan Islands in the South Pacific, another area where some scientists dispute the role of mantle plumes.

According to Kincaid, “A goal of geological oceanography is to understand the relationship between Earth’s convecting interior and our oceans over the entire spectrum of geologic time. This feeds directly into the very pressing need for understanding where Earth’s ocean-climate system is headed, which clearly hinges on our understanding of how it has worked in past.”

Natural soil bacteria pump new life into exhausted oil wells

Technology that enlists natural soil bacteria as 21st century roughnecks now is commercially available and poised to recover precious oil remaining in thousands of exhausted oil wells, according to a scientist who spoke here today. His report on a process termed microbially enhanced oil recovery (MEOR) was part of the 245th National Meeting & Exposition of the American Chemical Society, the world’s largest scientific society.

“The idea of using microbes to bring spent oil wells back to life dates to the early 1900s,” said Brian Clement, Ph.D. “That was the era of ‘easy-to-recover’ oil, and when a well played out, you just moved on and drilled another – knowing that 60-70 percent of the oil in that first reservoir remained untouched. We’re in a different era now. Oil is scarcer, and it makes sense to use MEOR. It can put about 10 percent of the oil in exhausted wells into barrels with low capital investment, low operating costs and little environmental impact.”

Clement is a senior scientist at Glori Energy, which is deploying its MEOR technology known as
AEROTM, for Activated Environment for Recovery of Oil. Other companies that have moved the technology to market include DuPont, which offers its MATRxTM MEOR technology and Titan Oil Recovery, Inc., which offers its Titan Process®. Clement’s talk was part of the symposium titled “The Interconnected World of Energy, Food and Water.”

Conventional oil production techniques rely on pressure that exists naturally in an underground reservoir to push oil to the surface, much like the pressure in a bottle of carbonated beverage. Clement explained that the pressure in a reservoir declines over time, and eventually it is too low to force oil to the surface. At that point, as much as 60 to 70 percent of the reservoir’s oil often remains in the ground.

MEOR can retrieve that oil by fostering various changes in the reservoir. Clement explained that the AEROTM System, for instance, piggybacks on waterflooding, a widely used process in which water is injected into the reservoir to force oil out of the well and to the surface. The system adds a customized formula of nutrients to the injection water to optimize its quality and stimulate the growth of native reservoir bacteria.

With the AERO System, microbes thrive and grow to increase oil production using two main mechanisms. First, they break down and metabolize oil at the oil-water interface, allowing the oil to flow more freely. Second, the microbes block existing water channels within the reservoir’s soil, forcing the water into new channels and driving more oil to the surface.

With the AERO System’s MEOR technology, oil field owners and operators can increase production from declining wells without having to invest in expensive, new infrastructure. Clement described tests in which the technology helped produce an additional 9-12 percent of the total oil remaining in reservoirs. The number may sound small, but translates into an additional $10 billion of oil from wells in the United States and more than $165 billion worldwide.

Ocean explorers want to get to the bottom of Galicia

Rice researchers who will study the Galicia rift off the coast of Spain this summer are (from left, front) Sarah Dean, Steve Danbom and Mari Tesi Sanjurjo and (from left, rear) Brian Jordan, Dale Sawyer and Julia Morgan. All but Morgan will make the 45-day cruise to map the terrain under the rift. -  Colin Zelt/Rice University
Rice researchers who will study the Galicia rift off the coast of Spain this summer are (from left, front) Sarah Dean, Steve Danbom and Mari Tesi Sanjurjo and (from left, rear) Brian Jordan, Dale Sawyer and Julia Morgan. All but Morgan will make the 45-day cruise to map the terrain under the rift. – Colin Zelt/Rice University

An international team of scientists and technicians led by Rice University will spend 45 days in the North Atlantic this summer to gather the most detailed information ever about the geology of the ocean basin that formed at what was once the center of Pangaea.

Geologists Dale Sawyer and Julia Morgan of Rice and Donna Shillington of Columbia University are leading the $6 million international project to study the Galicia rift northwest of the Spanish coast where, unusually, sediment has not deeply buried formations that have existed at the bottom of the ocean for millions of years.

A National Science Foundation (NSF) grant to Rice of more than $1.2 million will put five faculty members and graduate students on the 50-plus crew aboard the Seismic Vessel Marcus G. Langseth, owned by the NSF and operated by the Lamont-Doherty Earth Observatory.

The Langseth stopped in Galveston last month, where Sawyer took stock of its tools. He and Morgan have been waiting for their ship to come in since proposing the project eight years ago. “We had to wait for other seismic studies, creating a critical mass of work in the Atlantic in order to bring the ship from the Pacific Ocean to the Atlantic,” Sawyer said.

For 45 days the ship will trace a spiraling path — Sawyer compared it to mowing a lawn — over the rectangular 64-by-22.4 kilometer target. Throughout the journey, the 15 scientists and their technicians and students will analyze data and make critical decisions on optimizing data quality.

Sawyer will represent Rice on the ship, joined by graduate students Sarah Dean, Brian Jordan and Mari Tesi Sanjurjo and adjunct faculty lecturer Steve Danbom. All will begin analyzing the massive amount of data the ship will collect while on board, but the results will take years for geologists to fully process and understand, Sawyer said.

“Between 225 and 110 million years ago, the Atlantic Ocean opened up between Africa and North America, and the breakup propagated northward, opening a new ocean and pulling Spain and Portugal apart from what is now Newfoundland,” Sawyer said. “What makes this unusual is that it is a volcanic-starved rift.”

Elsewhere on the planet, lava flowed upward into rifts and created oceanic crust. “We found in the last 20 years that most margins are volcanic-dominated,” he said. “They actually pull apart, lots of magma comes up and the sea-floor spreading process begins immediately. Galicia is at the other end of the spectrum. Volcanic-dominated margins are thought to be caused by unusually high heat in the Earth’s mantle, while magma-starved margins are caused by cooler mantle rocks.

But the volcanic crust hasn’t reached the Galicia, where sections of the Earth’s mantle in the form of peridotite lie just under a thin layer of sediment. At this rift, the crust is neither oceanic nor continental, but of a different type. These formations may tell geologists a great deal about the rifts that appeared when the great continent split and began evolving into the map we know today.

“The sediments are thin,” Sawyer said, “so we can do seismic characterization and potentially drill into these rocks without having to go through 10 or 15 kilometers of sediment.

“One of our objectives with the 3-D survey is to find the best places to drill,” he said. “Now we can see the fans of sediment deposited on the broken and tilted continental crust blocks, but we don’t know when they broke and how quickly.” The images should allow them to gather core samples at the right places. “Then we have paleontological evidence we can date, and then we can start to know.”

To learn all this, the team will make 3-D images of the upper 20 kilometers of the rocks under the ocean. The RV Langseth will tow four cables, each 6 kilometers long, carrying nearly 2,000 hydrophones. The towed cables cover a width of 600 meters as they rake through the water. Constantly on the move, the ship fires an array of compressed air guns towed behind the ship. Airgun shots will be fired every 37 meters (once about every 16 seconds), and the seismometers will sense the reflections that come back from the seafloor and from rock layers. Using sound to see what eyes can’t, the signals are translated into an accurate three-dimensional image of the geological terrain below.

Before the Langseth sails from Vigo, Spain, on June 1, the German Research Vessel Poseidon and scientists from Germany and the United Kingdom will drop about 80 ocean-bottom seismometers in a grid on the same patch of ocean floor that the Rice-led team will survey.

“The ocean-bottom seismometers give us much better information about the speed of sound through the rocks, and that tells us a lot about what kind of rock the seismic wave is traveling through,” Sawyer said.

Several oil companies are interested in this work, Sawyer said. Although the sediments to be studied are thin and unlikely to yield oil or gas, other places in the world with similar magma-starved rifting and thick overlying sediments are virtually certain to contain hydrocarbons. Images taken through the thin Galicia sediments will provide information about what to expect in hydrocarbon-bearing areas elsewhere, he said.