How does a volcanic crater grow? Grab some TNT and find out

A new University at Buffalo study in the journal Geophysical Research Letters examines maar craters, which resemble the bowl-like cavities formed by meteorites but are in some ways more mysterious.

Scientists often can discern pertinent details about meteorites — when they struck, how large they were, the angle they approached Earth and other information — by measuring the diameter and volume of the impact crater.

Maar craters, which form when fissures of magma beneath Earth’s surface meet groundwater, causing volcanic explosions, are not as telling, scientists say. The possibility of multiple explosions at varying depths led most scientists to believe that measuring a maar’s size is not the best way to gauge the energy of individual explosions or determine future hazards.

UB geologist Greg A. Valentine, PhD, and other volcano researchers found instead that examining a maar’s shape and the distance it ejects magma, ash and other debris to be a more accurate barometer of the eruption’s force. The findings are important, he said, because they could assist scientists in estimating how big future volcano eruptions might b

“It’s something that, up until this point, had only been suspected,” said Valentine, a professor of geology and lead author of the Geophysical Research Letters paper. “The simulations we did prove that crater diameter is not a good indicator of explosion energy for these volcanoes.”
The scientists drew their conclusions on a series of UB-funded experiments conducted last summer at a test site in Ashford, N.Y. They built three test beds of gravel, limestone and asphalt. In the first experiment (see the video below) one charge of TNT and plastic explosive was detonated.

In subsequent experiments, the charge was divided into three parts and detonated individually at different depths. The final dimensions of each crater were about the same. That matters, according to Valentine, because it shows that it’s easy to overestimate the energy of explosions if one assumes that the crater comes from one blast, not several.

The dispersal of ejected material differed depending on the location of the charge. For example, the first experiment launched debris more than 50 feet from the crater. Debris from subsequent experiments simulating blasts further underground mostly went up in the air and fell back into the crater or around its rim. As a result, it forced dusty gas — like the ash that shut down air travel in Iceland and beyond in 2010 — into the surrounding air. This can be seen in the video below.

Although the experiments provided valuable information, Valentine said they were similar to a practice run. More detailed experiments are being planned for the near future, he said.

How does a volcanic crater grow? Grab some TNT and find out

A new University at Buffalo study in the journal Geophysical Research Letters examines maar craters, which resemble the bowl-like cavities formed by meteorites but are in some ways more mysterious.

Scientists often can discern pertinent details about meteorites — when they struck, how large they were, the angle they approached Earth and other information — by measuring the diameter and volume of the impact crater.

Maar craters, which form when fissures of magma beneath Earth’s surface meet groundwater, causing volcanic explosions, are not as telling, scientists say. The possibility of multiple explosions at varying depths led most scientists to believe that measuring a maar’s size is not the best way to gauge the energy of individual explosions or determine future hazards.

UB geologist Greg A. Valentine, PhD, and other volcano researchers found instead that examining a maar’s shape and the distance it ejects magma, ash and other debris to be a more accurate barometer of the eruption’s force. The findings are important, he said, because they could assist scientists in estimating how big future volcano eruptions might b

“It’s something that, up until this point, had only been suspected,” said Valentine, a professor of geology and lead author of the Geophysical Research Letters paper. “The simulations we did prove that crater diameter is not a good indicator of explosion energy for these volcanoes.”
The scientists drew their conclusions on a series of UB-funded experiments conducted last summer at a test site in Ashford, N.Y. They built three test beds of gravel, limestone and asphalt. In the first experiment (see the video below) one charge of TNT and plastic explosive was detonated.

In subsequent experiments, the charge was divided into three parts and detonated individually at different depths. The final dimensions of each crater were about the same. That matters, according to Valentine, because it shows that it’s easy to overestimate the energy of explosions if one assumes that the crater comes from one blast, not several.

The dispersal of ejected material differed depending on the location of the charge. For example, the first experiment launched debris more than 50 feet from the crater. Debris from subsequent experiments simulating blasts further underground mostly went up in the air and fell back into the crater or around its rim. As a result, it forced dusty gas — like the ash that shut down air travel in Iceland and beyond in 2010 — into the surrounding air. This can be seen in the video below.

Although the experiments provided valuable information, Valentine said they were similar to a practice run. More detailed experiments are being planned for the near future, he said.

Working under extreme conditions

Freezing temperatures, icing, snow and an unpredictable climate have a bigger impact on a platform in the Barents Sea than in the North Sea. -  Illustration: Ole Andre Hauge/ NettOp, UiS
Freezing temperatures, icing, snow and an unpredictable climate have a bigger impact on a platform in the Barents Sea than in the North Sea. – Illustration: Ole Andre Hauge/ NettOp, UiS

“Try to imagine changing a tire in freezing weather, snow and darkness,” says professor Tore Markeset, a specialist in cold climate technology at the University of Stavanger (UiS).

That is his way of visualising the challenges facing oil companies seeking to produce oil and gas from the far north of the Norwegian continental shelf (NCS).

Weather, winter darkness, vast distances, and safety and emergency response challenges for petroleum facilities in the Barents Sea will all be more extreme than in the North Sea.

“Compared with our expertise from the southern NCS, we know little about how to run an offshore production installation in a cold climate,” adds professor Ove Tobias Gudmestad at the UiS.

Both he and Markeset are active in teaching, research and finding solutions for developing fields in areas with Arctic conditions.

Opened

The Norwegian government opened the southern part of Norway’s Barents Sea sector for petroleum operations in the early 1980s. Activity was high but finds few, so interest declined.

But enthusiasm for these waters has recovered sharply in the recent past, particularly after the Skrugard oil discovery was made during 2011.

Promising seismic data, several large oil and gas finds and new technology mean that a growing number of oil companies are discussing opportunities to explore further north on the NCS.

Norway’s Statoil company announced earlier this autumn that it will more than treble its spending on technology for Arctic waters from NOK 80 million in 2012 to NOK 250 million next year.

The increased interest in the far north reflects not least clear government policies, with petroleum and energy minister Ola Borten Moe talking enthusiastically about Barents Sea activities.

Norway currently has one gas production facility operating in the southern Barents Sea. This Snøhvit field has been on stream since 2007.

And operator Eni aims to bring its Goliat oil development into production in 2014. Both that field and Snøhvit lie north-west of Hammerfest, 85 and 140 kilometres from land respectively.

Skrugard, for its part, is located roughly 100 kilometres further north-west from Snøhvit and is expected to come on stream during 2018.

Unpredictability

Climate is the main challenge for impatient oil companies and official agencies, says Gudmestad. “It’s unpredictability for much of the year which is really special about the far north.

“Weather conditions in these waters differ from the North Sea in terms of low temperatures, icing, fog, heavy snowfalls and sudden changes.”

The North Sea weather is easier to forecast, he notes. “When a low pressure area over Iceland moves east, we know it’ll bring bad weather and can plan operations accordingly.”

“In the Barents Sea, however, deep troughs of low pressure develop at the interface between ice and open water. These can’t be predicted, and may create sudden storms and hurricanes.”

Wind and waves have much to say for the safety of shipping, fishing and offshore operations. So accurate weather forecasts are important.

With fewer monitoring stations gathering data in the Arctic, however, forecasting in the Barents Sea is less accurate than in the North Sea.

Longer

The further north you go, the longer the winter becomes and the shorter the summer season. A good deal of offshore work must necessarily be squeezed into the latter. But the weather in these brief months may not allow planned activities to go ahead.

Arctic conditions can also mean that equipment fails or breaks down in unfamiliar ways, or more frequently than is the case in warmer regions.

Repairing broken equipment is also likely to take more time, or preventive maintenance may be necessary to make sure that the equipment functions properly.

“Things will take longer,” explains Markeset. “If you need to make repairs but the equipment is covered in snow, you’ll have to dig it out before the job can begin.

“It’s also harder to work in a temperature of -30°C than in 10°C. Putting small screws into place is a slow business with gloves on.”

The more frequently equipment breaks down and the longer it takes to repair, the less time will be available for producing oil and gas, he points out.

“When we invest in a production facility for the far north, it must be up and running for as much of the time as possible so that we can produce profitably.

“A huge problem would be faced if an installation failed to cope with the local climate. We’d be left with a massive and expensive machine which yields little.”

Winterization

Among the issues he and Gudmestad work on is winterisation – in other words, tailoring equipment and workplaces so that they can operate normally in a harsh winter climate.

They say that much could be different in the far north, including the need for special steels and equipment when temperatures fall low enough.

Plastics, rubber, metals and lubricants are examples of materials which change their properties under extreme cold, and which must be adapted to the Arctic environment.

Electrical systems, sensors, cables, valves, motors and pumps must all be specially manufactured. Piping, tanks and pumps containing liquids which could freeze have to be kept warm even if the installation shuts down to avoid being burst by frozen fluids.

An increased need to heat equipment and facilities and to provide lighting will boost energy consumption on installations – from heating cables in corridors and on helidecks, for instance.

Enclosed

The cold means that more equipment must be enclosed on units working in the Barents Sea than further south. And that in turn calls for more fans to prevent gas accumulations.

“Outfitting facilities in the far north will be more complex because of the need for heating and increased use of sensors to measure equipment condition,” observes Markeset.

“The companies will rely more on remote monitoring of and support for equipment via centres located in such places as Stavanger or Tromsø.

“Real-time diagnosis of systems will be crucial, making use of the internet, fibreoptic cables, satellites and specially developed sensors.

“A key role will also be played here by experts who could be located either at suppliers or in service companies in Germany, Italy, the USA or elsewhere.”

On the other hand, he points out, equipment protected through proper winterisation technology (such as being enclosed, with heat tracing and special designs) and better monitored with the aid of sensors may actually be more reliable and break down less frequently than in warmer waters.

Distances

Companies must also take account of longer distances to market for delivering oil and gas as well as for providing operational, maintenance and support services, Markeset notes.

“Operators have to make more thorough preparations, keep more spare parts on hand and perhaps have more and better expertise on board the production facility. That’ll all add to costs.”

In addition, facilities operating above the Arctic Circle must take 24-hour winter darkness into account. “We know that more accidents happen at night,” Markeset says.

“An important question which needs to be researched is how the perpetual winter darkness affects work processes on an offshore facility.”

Ice

The south-western Barents Sea is not much troubled by sea ice. The UiS scientists are accordingly looking at opportunities for field development and operation in an environment largely free of sea ice, but where drift ice must nevertheless be expected.

“Ice floes may weigh several hundred tonnes,” Gudmestad points out. “They can be tossed around by waves and driven with great force against an installation, causing serious damage.

“Our present equipment isn’t up to a collision with drift ice. That’ll limit the time we can drill in the northern Barents Sea – unlike year-round drilling in the North Sea.”

He points to the Shtokman gas field in the Russian sector of the Barents Sea, which lies in an area affected by both drift and pack ice.

“Pack ice involves extreme forces. It can exert pressure from every direction. A platform placed in the middle of it must be able to withstand such forces.

“In my view, we shouldn’t aim to position facilities on the NCS in pack ice – in other words, in the northern Barents Sea – to start with.”

He accordingly believes in a gradual advance northwards, in order to learn from conditions at each stage and to keep in step with technological progress.

“Although operations have begun in pack ice off Russia and Alaska, we should aim first and foremost to research and develop production solutions for the south-western Barents Sea.

“This is an area with extreme weather conditions and below-freezing temperatures, but where drift ice only appears now and then.”

Achievable


“Before deciding to build oil installations for the northern Barents Sea, we must know whether this is achievable,” Gudmestad explains.

“Plant availability must be satisfactory so that it’s profitable. We must also think about how to prevent accidents and how to respond should one nevertheless occur.”

His concern is to ensure that equipment, organisation and working methods are tailored to the Arctic environment, and thereby to reduce the probability of undesirable incidents.

“We must, for example, be certain that the evacuation system works in the Arctic. We can’t use freefall lifeboats if there’s ice on the water, to take a case in point.”

Threat


Both he and Markeset are concerned that oil spills in the far north pose a big threat to the vulnerable environment in these waters.

“Much of the existing oil spill clean-up equipment hasn’t been designed to operate in a cold climate and drift ice,” says Markeset.

“We must accordingly come up with better methods for collecting any oil spill in waters where sea ice could be encountered.”

The two UiS scientists do not get involved in Norwegian oil policies, and stress that determining how far north petroleum activities should extend on the NCS is a job for the politicians.

“Our role is to make it technically and organisationally possible to operate in the various sea areas when the government decides to set things going,” says Gudmestad.

“We must, for example, build even more safely in the Barents Sea than in the North and Norwegian Seas, and reduce the probability of oil spills even further.

“That’s precisely because the consequences of such discharges are greater in the far north. We must devote extensive resources and work to avoiding oil spills.”

Working under extreme conditions

Freezing temperatures, icing, snow and an unpredictable climate have a bigger impact on a platform in the Barents Sea than in the North Sea. -  Illustration: Ole Andre Hauge/ NettOp, UiS
Freezing temperatures, icing, snow and an unpredictable climate have a bigger impact on a platform in the Barents Sea than in the North Sea. – Illustration: Ole Andre Hauge/ NettOp, UiS

“Try to imagine changing a tire in freezing weather, snow and darkness,” says professor Tore Markeset, a specialist in cold climate technology at the University of Stavanger (UiS).

That is his way of visualising the challenges facing oil companies seeking to produce oil and gas from the far north of the Norwegian continental shelf (NCS).

Weather, winter darkness, vast distances, and safety and emergency response challenges for petroleum facilities in the Barents Sea will all be more extreme than in the North Sea.

“Compared with our expertise from the southern NCS, we know little about how to run an offshore production installation in a cold climate,” adds professor Ove Tobias Gudmestad at the UiS.

Both he and Markeset are active in teaching, research and finding solutions for developing fields in areas with Arctic conditions.

Opened

The Norwegian government opened the southern part of Norway’s Barents Sea sector for petroleum operations in the early 1980s. Activity was high but finds few, so interest declined.

But enthusiasm for these waters has recovered sharply in the recent past, particularly after the Skrugard oil discovery was made during 2011.

Promising seismic data, several large oil and gas finds and new technology mean that a growing number of oil companies are discussing opportunities to explore further north on the NCS.

Norway’s Statoil company announced earlier this autumn that it will more than treble its spending on technology for Arctic waters from NOK 80 million in 2012 to NOK 250 million next year.

The increased interest in the far north reflects not least clear government policies, with petroleum and energy minister Ola Borten Moe talking enthusiastically about Barents Sea activities.

Norway currently has one gas production facility operating in the southern Barents Sea. This Snøhvit field has been on stream since 2007.

And operator Eni aims to bring its Goliat oil development into production in 2014. Both that field and Snøhvit lie north-west of Hammerfest, 85 and 140 kilometres from land respectively.

Skrugard, for its part, is located roughly 100 kilometres further north-west from Snøhvit and is expected to come on stream during 2018.

Unpredictability

Climate is the main challenge for impatient oil companies and official agencies, says Gudmestad. “It’s unpredictability for much of the year which is really special about the far north.

“Weather conditions in these waters differ from the North Sea in terms of low temperatures, icing, fog, heavy snowfalls and sudden changes.”

The North Sea weather is easier to forecast, he notes. “When a low pressure area over Iceland moves east, we know it’ll bring bad weather and can plan operations accordingly.”

“In the Barents Sea, however, deep troughs of low pressure develop at the interface between ice and open water. These can’t be predicted, and may create sudden storms and hurricanes.”

Wind and waves have much to say for the safety of shipping, fishing and offshore operations. So accurate weather forecasts are important.

With fewer monitoring stations gathering data in the Arctic, however, forecasting in the Barents Sea is less accurate than in the North Sea.

Longer

The further north you go, the longer the winter becomes and the shorter the summer season. A good deal of offshore work must necessarily be squeezed into the latter. But the weather in these brief months may not allow planned activities to go ahead.

Arctic conditions can also mean that equipment fails or breaks down in unfamiliar ways, or more frequently than is the case in warmer regions.

Repairing broken equipment is also likely to take more time, or preventive maintenance may be necessary to make sure that the equipment functions properly.

“Things will take longer,” explains Markeset. “If you need to make repairs but the equipment is covered in snow, you’ll have to dig it out before the job can begin.

“It’s also harder to work in a temperature of -30°C than in 10°C. Putting small screws into place is a slow business with gloves on.”

The more frequently equipment breaks down and the longer it takes to repair, the less time will be available for producing oil and gas, he points out.

“When we invest in a production facility for the far north, it must be up and running for as much of the time as possible so that we can produce profitably.

“A huge problem would be faced if an installation failed to cope with the local climate. We’d be left with a massive and expensive machine which yields little.”

Winterization

Among the issues he and Gudmestad work on is winterisation – in other words, tailoring equipment and workplaces so that they can operate normally in a harsh winter climate.

They say that much could be different in the far north, including the need for special steels and equipment when temperatures fall low enough.

Plastics, rubber, metals and lubricants are examples of materials which change their properties under extreme cold, and which must be adapted to the Arctic environment.

Electrical systems, sensors, cables, valves, motors and pumps must all be specially manufactured. Piping, tanks and pumps containing liquids which could freeze have to be kept warm even if the installation shuts down to avoid being burst by frozen fluids.

An increased need to heat equipment and facilities and to provide lighting will boost energy consumption on installations – from heating cables in corridors and on helidecks, for instance.

Enclosed

The cold means that more equipment must be enclosed on units working in the Barents Sea than further south. And that in turn calls for more fans to prevent gas accumulations.

“Outfitting facilities in the far north will be more complex because of the need for heating and increased use of sensors to measure equipment condition,” observes Markeset.

“The companies will rely more on remote monitoring of and support for equipment via centres located in such places as Stavanger or Tromsø.

“Real-time diagnosis of systems will be crucial, making use of the internet, fibreoptic cables, satellites and specially developed sensors.

“A key role will also be played here by experts who could be located either at suppliers or in service companies in Germany, Italy, the USA or elsewhere.”

On the other hand, he points out, equipment protected through proper winterisation technology (such as being enclosed, with heat tracing and special designs) and better monitored with the aid of sensors may actually be more reliable and break down less frequently than in warmer waters.

Distances

Companies must also take account of longer distances to market for delivering oil and gas as well as for providing operational, maintenance and support services, Markeset notes.

“Operators have to make more thorough preparations, keep more spare parts on hand and perhaps have more and better expertise on board the production facility. That’ll all add to costs.”

In addition, facilities operating above the Arctic Circle must take 24-hour winter darkness into account. “We know that more accidents happen at night,” Markeset says.

“An important question which needs to be researched is how the perpetual winter darkness affects work processes on an offshore facility.”

Ice

The south-western Barents Sea is not much troubled by sea ice. The UiS scientists are accordingly looking at opportunities for field development and operation in an environment largely free of sea ice, but where drift ice must nevertheless be expected.

“Ice floes may weigh several hundred tonnes,” Gudmestad points out. “They can be tossed around by waves and driven with great force against an installation, causing serious damage.

“Our present equipment isn’t up to a collision with drift ice. That’ll limit the time we can drill in the northern Barents Sea – unlike year-round drilling in the North Sea.”

He points to the Shtokman gas field in the Russian sector of the Barents Sea, which lies in an area affected by both drift and pack ice.

“Pack ice involves extreme forces. It can exert pressure from every direction. A platform placed in the middle of it must be able to withstand such forces.

“In my view, we shouldn’t aim to position facilities on the NCS in pack ice – in other words, in the northern Barents Sea – to start with.”

He accordingly believes in a gradual advance northwards, in order to learn from conditions at each stage and to keep in step with technological progress.

“Although operations have begun in pack ice off Russia and Alaska, we should aim first and foremost to research and develop production solutions for the south-western Barents Sea.

“This is an area with extreme weather conditions and below-freezing temperatures, but where drift ice only appears now and then.”

Achievable


“Before deciding to build oil installations for the northern Barents Sea, we must know whether this is achievable,” Gudmestad explains.

“Plant availability must be satisfactory so that it’s profitable. We must also think about how to prevent accidents and how to respond should one nevertheless occur.”

His concern is to ensure that equipment, organisation and working methods are tailored to the Arctic environment, and thereby to reduce the probability of undesirable incidents.

“We must, for example, be certain that the evacuation system works in the Arctic. We can’t use freefall lifeboats if there’s ice on the water, to take a case in point.”

Threat


Both he and Markeset are concerned that oil spills in the far north pose a big threat to the vulnerable environment in these waters.

“Much of the existing oil spill clean-up equipment hasn’t been designed to operate in a cold climate and drift ice,” says Markeset.

“We must accordingly come up with better methods for collecting any oil spill in waters where sea ice could be encountered.”

The two UiS scientists do not get involved in Norwegian oil policies, and stress that determining how far north petroleum activities should extend on the NCS is a job for the politicians.

“Our role is to make it technically and organisationally possible to operate in the various sea areas when the government decides to set things going,” says Gudmestad.

“We must, for example, build even more safely in the Barents Sea than in the North and Norwegian Seas, and reduce the probability of oil spills even further.

“That’s precisely because the consequences of such discharges are greater in the far north. We must devote extensive resources and work to avoiding oil spills.”

Magnesium oxide: From Earth to super-Earth

The mantles of Earth and other rocky planets are rich in magnesium and oxygen. Due to its simplicity, the mineral magnesium oxide is a good model for studying the nature of planetary interiors. New work from a team led by Carnegie’s Stewart McWilliams studied how magnesium oxide behaves under the extreme conditions deep within planets and found evidence that alters our understanding of planetary evolution. It is published November 22 by Science Express.

Magnesium oxide is particularly resistant to changes when under intense pressures and temperatures. Theoretical predictions claim that it has just three unique states with different structures and properties present under planetary conditions: solid under ambient conditions (such as on the Earth’s surface), liquid at high temperatures, and another structure of the solid at high pressure. The latter structure has never been observed in nature or in experiments.

McWilliams and his team observed magnesium oxide between pressures of about 3 million times normal atmospheric pressure (0.3 terapascals) to 14 million times atmospheric pressure (1.4 terapascals) and at temperatures reaching as high as 90,000 degrees Fahrenheit (50,000 Kelvin), conditions that range from those at the center of our Earth to those of large exo-planet super-Earths. Their observations indicate substantial changes in molecular bonding as the magnesium oxide responds to these various conditions, including a transformation to a new high-pressure solid phase.

In fact, when melting, there are signs that magnesium oxide changes from an electrically insulating material like quartz (meaning that electrons do not flow easily) to a metal similar to iron (meaning that electrons do flow easily through the material).

Drawing from these and other recent observations, the team concluded that while magnesium oxide is solid and non-conductive under conditions found on Earth in the present day, the early Earth’s magma ocean might have been able to generate a magnetic field. Likewise, the metallic, liquid phase of magnesium oxide can exist today in the deep mantles of super-Earth planets, as can the newly observed solid phase.

“Our findings blur the line between traditional definitions of mantle and core material and provide a path for understanding how young or hot planets can generate and sustain magnetic fields,” McWilliams said.

“This pioneering study takes advantage of new laser techniques to explore the nature of the materials that comprise the wide array of planets being discovered outside of our Solar System,” said Russell Hemley, director of Carnegie’s Geophysical Laboratory. “These methods allow investigations of the behavior of these materials at pressures and temperatures never before explored experimentally

Magnesium oxide: From Earth to super-Earth

The mantles of Earth and other rocky planets are rich in magnesium and oxygen. Due to its simplicity, the mineral magnesium oxide is a good model for studying the nature of planetary interiors. New work from a team led by Carnegie’s Stewart McWilliams studied how magnesium oxide behaves under the extreme conditions deep within planets and found evidence that alters our understanding of planetary evolution. It is published November 22 by Science Express.

Magnesium oxide is particularly resistant to changes when under intense pressures and temperatures. Theoretical predictions claim that it has just three unique states with different structures and properties present under planetary conditions: solid under ambient conditions (such as on the Earth’s surface), liquid at high temperatures, and another structure of the solid at high pressure. The latter structure has never been observed in nature or in experiments.

McWilliams and his team observed magnesium oxide between pressures of about 3 million times normal atmospheric pressure (0.3 terapascals) to 14 million times atmospheric pressure (1.4 terapascals) and at temperatures reaching as high as 90,000 degrees Fahrenheit (50,000 Kelvin), conditions that range from those at the center of our Earth to those of large exo-planet super-Earths. Their observations indicate substantial changes in molecular bonding as the magnesium oxide responds to these various conditions, including a transformation to a new high-pressure solid phase.

In fact, when melting, there are signs that magnesium oxide changes from an electrically insulating material like quartz (meaning that electrons do not flow easily) to a metal similar to iron (meaning that electrons do flow easily through the material).

Drawing from these and other recent observations, the team concluded that while magnesium oxide is solid and non-conductive under conditions found on Earth in the present day, the early Earth’s magma ocean might have been able to generate a magnetic field. Likewise, the metallic, liquid phase of magnesium oxide can exist today in the deep mantles of super-Earth planets, as can the newly observed solid phase.

“Our findings blur the line between traditional definitions of mantle and core material and provide a path for understanding how young or hot planets can generate and sustain magnetic fields,” McWilliams said.

“This pioneering study takes advantage of new laser techniques to explore the nature of the materials that comprise the wide array of planets being discovered outside of our Solar System,” said Russell Hemley, director of Carnegie’s Geophysical Laboratory. “These methods allow investigations of the behavior of these materials at pressures and temperatures never before explored experimentally

GOCE’s second mission improving gravity map

ESA’s GOCE gravity satellite has already delivered the most accurate gravity map of Earth, but its orbit is now being lowered in order to obtain even better results.

The Gravity field and steady-state Ocean Circulation Explorer (GOCE) has been orbiting Earth since March 2009, reaching its ambitious objective to map our planet’s gravity with unrivalled precision.

Although the planned mission has been completed, the fuel consumption was much lower than anticipated because of the low solar activity over the last two years. This has enabled ESA to extend GOCE’s life, improving the quality of the gravity model.

To be able to measure the strength of Earth’s gravity, the satellite was flying in an extraordinarily low orbit about 255 km high – about 500 km lower than most Earth observation satellites.

Based on a clear preference from the GOCE user community, ESA’s Earth Scientific Advisory Committee recommended lowering the orbit to 235 km starting in August.

Lowering the orbit increases the accuracy and resolution of GOCE’s measurements, improving our view of smaller ocean dynamics such as eddy currents.

The control team began the manoeuvres in August, lowering GOCE by about 300 m per day.

After coming down by 8.6 km, the satellite’s performance and new environment were assessed. Now, GOCE is again being lowered while continuing its gravity mapping. Finally, it is expected to reach 235 km in February.

As the orbit drops, atmospheric drag increasingly pulls the satellite towards Earth. But GOCE was designed to fly low, the tiny thrust of its ion engine continuously compensating for any drag.

The expected increase in data quality is so high that scientists are calling it GOCE’s ‘second mission.’

“For us at ESA, GOCE has been a fantastic mission and it continues to surprise us,” said Volker Liebig, ESA’s Director of Earth Observation Programmes.

“What the team of ESA engineers is now doing has not been done before and it poses a challenge. But it will also trigger new research in the field of gravity based on the high-resolution data we are expecting.”

The first ‘geoid’ based on GOCE’s gravity measurements was unveiled in June 2010. It is the surface of an ideal global ocean in the absence of tides and currents, shaped only by gravity.

A geoid is a crucial reference for conducting precise measurements of ocean circulation, sea-level change and ice dynamics.

The mission has also been providing new insight into air density and wind in space, and its information was recently used to produce the first global high-resolution map of the boundary between Earth’s crust and mantle.

GOCE’s second mission improving gravity map

ESA’s GOCE gravity satellite has already delivered the most accurate gravity map of Earth, but its orbit is now being lowered in order to obtain even better results.

The Gravity field and steady-state Ocean Circulation Explorer (GOCE) has been orbiting Earth since March 2009, reaching its ambitious objective to map our planet’s gravity with unrivalled precision.

Although the planned mission has been completed, the fuel consumption was much lower than anticipated because of the low solar activity over the last two years. This has enabled ESA to extend GOCE’s life, improving the quality of the gravity model.

To be able to measure the strength of Earth’s gravity, the satellite was flying in an extraordinarily low orbit about 255 km high – about 500 km lower than most Earth observation satellites.

Based on a clear preference from the GOCE user community, ESA’s Earth Scientific Advisory Committee recommended lowering the orbit to 235 km starting in August.

Lowering the orbit increases the accuracy and resolution of GOCE’s measurements, improving our view of smaller ocean dynamics such as eddy currents.

The control team began the manoeuvres in August, lowering GOCE by about 300 m per day.

After coming down by 8.6 km, the satellite’s performance and new environment were assessed. Now, GOCE is again being lowered while continuing its gravity mapping. Finally, it is expected to reach 235 km in February.

As the orbit drops, atmospheric drag increasingly pulls the satellite towards Earth. But GOCE was designed to fly low, the tiny thrust of its ion engine continuously compensating for any drag.

The expected increase in data quality is so high that scientists are calling it GOCE’s ‘second mission.’

“For us at ESA, GOCE has been a fantastic mission and it continues to surprise us,” said Volker Liebig, ESA’s Director of Earth Observation Programmes.

“What the team of ESA engineers is now doing has not been done before and it poses a challenge. But it will also trigger new research in the field of gravity based on the high-resolution data we are expecting.”

The first ‘geoid’ based on GOCE’s gravity measurements was unveiled in June 2010. It is the surface of an ideal global ocean in the absence of tides and currents, shaped only by gravity.

A geoid is a crucial reference for conducting precise measurements of ocean circulation, sea-level change and ice dynamics.

The mission has also been providing new insight into air density and wind in space, and its information was recently used to produce the first global high-resolution map of the boundary between Earth’s crust and mantle.

USA’s ancient hurricane belt and the US-Canada equator

Mountain and valley near G.B. Schley Fjord, North Greenland: researchers found a strange limestone in a 400 meter high mountain. The 150 metre thick brachiopod coquina is shown in yellow. Note the geologist camp for scale of mountain. At the bottom left is an inserted view showing how the rock appears in close-up. White areas in the dark limestone are brachiopod shells. -  Christian Mac Ørum Rasmussen
Mountain and valley near G.B. Schley Fjord, North Greenland: researchers found a strange limestone in a 400 meter high mountain. The 150 metre thick brachiopod coquina is shown in yellow. Note the geologist camp for scale of mountain. At the bottom left is an inserted view showing how the rock appears in close-up. White areas in the dark limestone are brachiopod shells. – Christian Mac Ørum Rasmussen

The recent storms that have battered settlements on the east coast of America may have been much more frequent in the region 450 million years ago, according to scientists.

New research pinpointing the positions of the Equator and the landmasses of the USA, Canada and Greenland, during the Ordovician Period 450 million years ago, indicates that the equator ran down the western side of North America with a hurricane belt to the east.

The hurricane belt would have affected an area covering modern day New York State, New Jersey and most of the eastern seaboard of the USA.

An international research team led by Durham University, UK, used the distribution of fossils and sediments to map the line of the Ordovician Equator down to southern California.

The study, published in the journal Geology, is the first to accurately locate and map the ancient Equator and adjacent tropical zones. Previous studies had fuelled controversy about the precise location of the ancient equator. The researchers say the new results show how fossils and sediments can accurately track equatorial change and continental shifts over time.

Co-lead author Professor David Harper, Department of Earth Sciences, Durham University, UK, said: “The equator, equatorial zones and hurricane belts were in quite different places in the Ordovician. It is likely that the weather forecast would have featured frequent hurricane-force storms in New York and other eastern states, and warmer, more tropical weather from Seattle to California.”

Since Polar Regions existed 450 million years ago, the scientists believe that there would have been similar climate belts to those of today.

The research team from Durham University, UK, and universities in Canada, Denmark and the USA, discovered a belt of undisturbed fossils and sediments -deposits of shellfish- more than 6000 km long stretching from the south-western United States to North Greenland. The belt also lacks typical storm-related sedimentary features where the deposits are disturbed by bad weather. The researchers say that this shows that the Late Ordovician equatorial zone, like the equatorial zone today, had few hurricane-grade storms.

In contrast, sedimentary deposits recorded on either side of the belt provide evidence of disturbance by severe storms. Hurricanes tend to form in the areas immediately outside of equatorial zones where temperatures of at least 260C combine with the Earth’s rotation to create storms. The researchers believe that hurricane belts would probably have existed on either side of the ancient equator, within the tropics.

The position of the equatorial belt, defined by undisturbed fossil accumulations and sediments, is coincident with the Late Ordovician equator interpreted from magnetic records (taken from rocks of a similar age from the region). This provides both a precise equatorial location and confirms that the Earth’s magnetic field operated much in the same way as it does today.

The scientists pieced together the giant jigsaw map using the evidence of the disturbed and undisturbed sedimentary belts together with burrows and shells. Using the findings from these multiple sites, they were able to see that North America sat on either side of the Equator.

Co-author Christian Rasmussen, University of Copenhagen, said: “The layers of the earth build up over time and are commonly exposed by plate tectonics. We are able to use these ancient rocks and their fossils as evidence of the past to create an accurate map of the Ordovician globe.”

Professor Harper added: “The findings show that we had the same climate belts of today and we can see where North America was located 450 million years ago, essentially on the Equator.”

“While the Equator has remained in approximately the same place over time, the landmasses have shifted dramatically over time through tectonic movements. The undisturbed fossil belt helps to locate the exact position of the ancient Laurentian landmass, now known as North America.”

USA’s ancient hurricane belt and the US-Canada equator

Mountain and valley near G.B. Schley Fjord, North Greenland: researchers found a strange limestone in a 400 meter high mountain. The 150 metre thick brachiopod coquina is shown in yellow. Note the geologist camp for scale of mountain. At the bottom left is an inserted view showing how the rock appears in close-up. White areas in the dark limestone are brachiopod shells. -  Christian Mac Ørum Rasmussen
Mountain and valley near G.B. Schley Fjord, North Greenland: researchers found a strange limestone in a 400 meter high mountain. The 150 metre thick brachiopod coquina is shown in yellow. Note the geologist camp for scale of mountain. At the bottom left is an inserted view showing how the rock appears in close-up. White areas in the dark limestone are brachiopod shells. – Christian Mac Ørum Rasmussen

The recent storms that have battered settlements on the east coast of America may have been much more frequent in the region 450 million years ago, according to scientists.

New research pinpointing the positions of the Equator and the landmasses of the USA, Canada and Greenland, during the Ordovician Period 450 million years ago, indicates that the equator ran down the western side of North America with a hurricane belt to the east.

The hurricane belt would have affected an area covering modern day New York State, New Jersey and most of the eastern seaboard of the USA.

An international research team led by Durham University, UK, used the distribution of fossils and sediments to map the line of the Ordovician Equator down to southern California.

The study, published in the journal Geology, is the first to accurately locate and map the ancient Equator and adjacent tropical zones. Previous studies had fuelled controversy about the precise location of the ancient equator. The researchers say the new results show how fossils and sediments can accurately track equatorial change and continental shifts over time.

Co-lead author Professor David Harper, Department of Earth Sciences, Durham University, UK, said: “The equator, equatorial zones and hurricane belts were in quite different places in the Ordovician. It is likely that the weather forecast would have featured frequent hurricane-force storms in New York and other eastern states, and warmer, more tropical weather from Seattle to California.”

Since Polar Regions existed 450 million years ago, the scientists believe that there would have been similar climate belts to those of today.

The research team from Durham University, UK, and universities in Canada, Denmark and the USA, discovered a belt of undisturbed fossils and sediments -deposits of shellfish- more than 6000 km long stretching from the south-western United States to North Greenland. The belt also lacks typical storm-related sedimentary features where the deposits are disturbed by bad weather. The researchers say that this shows that the Late Ordovician equatorial zone, like the equatorial zone today, had few hurricane-grade storms.

In contrast, sedimentary deposits recorded on either side of the belt provide evidence of disturbance by severe storms. Hurricanes tend to form in the areas immediately outside of equatorial zones where temperatures of at least 260C combine with the Earth’s rotation to create storms. The researchers believe that hurricane belts would probably have existed on either side of the ancient equator, within the tropics.

The position of the equatorial belt, defined by undisturbed fossil accumulations and sediments, is coincident with the Late Ordovician equator interpreted from magnetic records (taken from rocks of a similar age from the region). This provides both a precise equatorial location and confirms that the Earth’s magnetic field operated much in the same way as it does today.

The scientists pieced together the giant jigsaw map using the evidence of the disturbed and undisturbed sedimentary belts together with burrows and shells. Using the findings from these multiple sites, they were able to see that North America sat on either side of the Equator.

Co-author Christian Rasmussen, University of Copenhagen, said: “The layers of the earth build up over time and are commonly exposed by plate tectonics. We are able to use these ancient rocks and their fossils as evidence of the past to create an accurate map of the Ordovician globe.”

Professor Harper added: “The findings show that we had the same climate belts of today and we can see where North America was located 450 million years ago, essentially on the Equator.”

“While the Equator has remained in approximately the same place over time, the landmasses have shifted dramatically over time through tectonic movements. The undisturbed fossil belt helps to locate the exact position of the ancient Laurentian landmass, now known as North America.”