How earthquake safety measures could have saved thousands of lives in Nepal

April 30, 2015

Poorly built houses were destroyed in the Credit: Domenico/flickr, CC BY-SA

Earthquake engineers often say earthquakes don’t kill people, collapsing buildings do. The tragic loss of life that followed the huge earthquake in Nepal on April 25 occurred despite the fact that the country is among the world’s leaders in community-based efforts to reduce disaster risk. But poverty, corruption, and poor governance have all led to a failure to enforce building codes – as has a shortage of skilled engineers, planners and architects.

Sadly the country was on its way to deploying knowledge and skills to tackle its long-term vulnerability just as the ground shook.

So why aren’t more buildings designed to withstand shaking – even extreme shaking.

To keep buildings standing, it is essential to have adequate building and planning codes, as well as proper training and certification for professionals such as engineers, architects, and planners. But having certification and codes on paper does not ensure implementation or compliance. Nepal does, after all, have some of these things. Laws and regulations must also be monitored and enforced. That is not easy in a country such as Nepal, which has isolated villages, a history of conflict and many governance difficulties.

Table of Contents

Vast vulnerability

Financial as well as social resources are needed to set up earthquake resistant buildings. Governments at all levels need to be functioning and competent in order to engage with processes such as urban planning and earthquake-resistant construction. Citizens must trust and have the opportunity to work with their governments, including the law enforcement and judicial sectors.

It’s not just about buildings. Many non-structural measures are needed to ensure survivability in earthquakes. Appliances such as televisions, microwaves, hot water boilers, and refrigerators (which do not always exist in Nepalese homes) must be securely fastened to the floors and the walls. Otherwise, they move and topple, killing as readily as building collapse. Even in affluent earthquake-prone locations such as New Zealand and California, we see shockingly low rates of households enacting these basic measures.

But Nepal is not New Zealand or California. It has been wracked by conflict and troubled by unstable governments, not to mention the governance issues caused by being sandwiched between China and India. It has long had high poverty and low formal education rates.

Despite recent improvements, Nepal still lags behind other countries when it comes to human development and it is still seen as highly corrupt. It also scores badly on child health and gender equality measurements.

When families struggle daily for enough food to keep their children healthy, they are not likely to spend time thinking about making their home earthquake resistant.

And when children are malnourished and stunted, they perform worse in school. That leads to long-term education inadequacies that prevent them from developing into adults with the skills to lobby for adequate and enforced building codes. What’s more, when women lack the same opportunities as men, half the population is excluded from demanding and enacting good governance.

All these factors contribute to the country’s vulnerability. All these factors have led to housing and infrastructure prone to collapse in an earthquake.

Rebuilding a nation

None of these things can be solved overnight. Tackling vulnerability is a long-term process, yet earthquakes strike and bring down buildings in seconds and minutes.

As the earthquake struck, Nepalese people were working hard to overcome these vulnerability conditions. My friends and colleagues from the country have taught me plenty about retrofitting buildings and constructing earthquake-resistant homes.

They travelled to communities with small shake tables, which are used to simulate earthquakes by shaking model houses or building components, showing the difference between an earthquake-resistant house and a non-earthquake resistant house. They made many schools safe. They taught school children and their parents about earthquake-safe behaviour.

These efforts saved hundreds of lives, if not more, during the recent tremors. With a few more decades, a mere instant in geological time, they could have made Nepal comparatively safe from earthquake disasters despite earthquakes. In that time, so many more buildings would have been retrofitted, we might have had adequate building code enforcement, and most importantly, an earthquake-educated and vulnerability-educated generation would have started to take power.

Nepal must now continue these efforts in order to avoid similar future devastation. We can be optimistic. Education is happening – for boys and girls. Women are increasingly being given equal opportunities as men. This means the Nepalese people are taking charge of their own health, their own environment, and their own sustainability. That is vulnerability reduction over the long-term.

Note : The above story is based on materials provided by The Conversation.
This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives).

Rare whale fossil found in Panama clarifies evolution of sperm whale

April 30, 2015

This is the evolutionary tree of sperm whales, showing the relationships of extinct and living species, and when reduction of the spermaceti organ took place. Credit: Natural History Museum of Los Angeles County

Almost since the time of Melville’s epic hunt, scientists have been fascinated by the remarkable attributes of the sperm whale and its kin, the smaller pigmy and dwarf whales. Capable of diving to great depths and gifted with an acute sense of echolocation, these animals have remained inseparable from maritime lore.
An international team of scientists, led by the Natural History Museum of Los Angeles County’s Curator of Marine Mammals Dr. Jorge Velez-Juarbe, has discovered a new species of an extinct pigmy sperm whale from Panama that clarifies key aspects of the evolution of these magnificent animals. The report published in the journal PLOS ONE reveals an unexpected level of complexity in the evolution of the spermaceti of these whales, an organ located within the head that plays a key role in the generation of sound and in the whale’s capacity for echolocation.

Whales, dolphins, and porpoises have a long fossil record, which documents the evolutionary journey from terrestrial ancestors to the fully marine organisms of today. Such a record has enabled scientists to better understand how changes in climate and continental distribution have transformed the marine ecosystems and the diversity life forms that they host. Yet, the poor fossil record of the smaller relatives of the well-known sperm whale, the 8- to 12-foot-long pigmy and dwarf sperm whales, has limited our understanding of the evolution of these mysterious animals.

Discovered and studied by a team of scientists from the NHM, Iowa State University, and the Smithsonian Tropical Research Institute, the new Panamanian fossil whale affords fresh evidence to this old problem.

“The new discovery gives us a better understanding of the ancient distribution of these poorly known relatives of the sperm whale,” said Dr. Velez-Juarbe. “Previously we knew of similarly-aged pigmy and dwarf whales from Baja California and Peru, but this new fossil fills in an important geographic gap in the group’s ancient distribution.”

The new whale species, named Nanokogia isthmia after the Isthmus of Panama, is known from the well-preserved skulls of two individuals, which remains were unearthed at a sea cliff along the Caribbean coast of Panama and from rock layers dated to about 7 million years ago. “Our study is part of a larger scientific effort aimed at understanding the changes in the marine habitats that resulted from the complete closure of the Isthmus of Panama,” said Dr. Velez-Juarbe, referring to the separation between the eastern Pacific Ocean and the Caribbean Sea that took place sometime within the last 10 million years.

These rare fossils are among a handful other fossil whales known from Panama, where fossil hunting is often difficult due to the dense vegetation and thick soils that often covers the surface. Resurrected from their million-year-old entombment, the new fossils tell us that the evolution of characteristics related to sound emission and echolocation was far more complex than previously envisioned. The new study shows that at one time, these small sperm whales had a much larger spermaceti organ, which got downsized at least twice during the evolutionary history of these animals (including the evolutionary event that gave origin to the living pigmy and dwarf sperm whales). The reasons of this size reduction remain unclear; scientists would have to find more complete skeletons of Nanokogia and other closely related species to untangle the question. For now, Dr. Velez-Juarbe continues to explore the prehistoric seas of Central America–Captain Ahab would have been proud.

Reference:
Jorge Velez-Juarbe , Aaron R. Wood, Carlos De Gracia, Austin J. W. Hendy. Evolutionary Patterns among Living and Fossil Kogiid Sperm Whales: Evidence from the Neogene of Central America. PLoS One, 2015 DOI: 10.1371/journal.pone.0123909

Note: The above story is based on materials provided by Natural History Museum of Los Angeles County.

How cracking explains underwater volcanoes and the Hawaiian bend

April 29, 2015

Na Pali Coast on Kauai island (stock image). It has long been accepted that as Earth’s plates move over fixed hot spots in its underlying mantle, resulting eruptions create chains of now extinct underwater volcanoes or ‘seamounts’. One of the most famous is the Hawaiian-Emperor chain in the northern Pacific Ocean. The seamounts of that chain are composed mainly of ocean island basalts — the type of lava that erupts above hot spots. Credit: © SergiyN / Fotolia

University of Sydney geoscientists have helped prove that some of the ocean’s underwater volcanoes did not erupt from hot spots in Earth’s mantle but instead formed from cracks or fractures in the oceanic crust.

The discovery helps explain the spectacular bend in the famous underwater range, the Hawaiian-Emperor seamount chain, where the bottom half kinks at a sixty degree angle to the east of its top half.

“There has been speculation among geoscientists for decades that some underwater volcanoes form because of fracturing,” said Professor Dietmar Muller, from the University of Sydney’s School of Geosciences in Australia and an author on the research findings published in Nature Geoscience.

“But this is the first comprehensive analysis of the rocks that form in this setting that confirms their origins.”

It has long been accepted that as Earth’s plates move over fixed hot spots in its underlying mantle, resulting eruptions create chains of now extinct underwater volcanoes or ‘seamounts’.

One of the most famous is the Hawaiian-Emperor chain in the northern Pacific Ocean. The seamounts of that chain are composed mainly of ocean island basalts — the type of lava that erupts above hot spots.

But north of the Hawaiian chain, in a formation called the Musicians Ridge, researchers found samples from seamounts that were not made up of the ocean island basalts you would expect from plates moving over a hot spot.

“The oldest part of the Musicians Ridge formed approximately 90 million years ago from hot spots but these new samples are only about 50 million years old and have a different geochemistry,” said Professor Muller.

“They did not form because of a hot spot but because of plates cracking open at their weakest point, allowing new magma to rise to the seabed and restart the formation of underwater volcanoes. They are near extinct hot spot volcanoes because that hot spot action millions of years earlier helped weaken the crust (the layer directly above the mantle) where new volcanoes now form.”

Vulnerable spots in Earth’s plates crack when they are stressed, in this case due to movement of the Pacific Plate which started to dive or submerge back into Earth’s crust at its northern and western edges around 50 million years ago.

The formation of these younger seamounts caused by the deformation of the Pacific Plate at its margins suggests a link to the unique bend in the Hawaiian-Emperor chain.

“We believe tectonic changes along the margins of the Pacific Plate around 50 million years ago put the weakest points of the Pacific Ocean crust under tension and created the youngest Musicians Ridge seamounts,” said Professor Muller.

“It also caused the flow in the slowly convecting mantle under the Pacific to change dramatically, to the point that the Hawaiian hot spot in Earth’s mantle changed its position.

“The resulting seamounts along the Hawaii-Emperor chain changed their position accordingly and the bend was born.”

This work provides a solid foundation for understanding other ‘non-hot spot’ volcanism seen elsewhere, for example the Puka Puka Ridge in the South Pacific.

Reference:
John M. O’Connor, Kaj Hoernle, R. Dietmar Müller, Jason P. Morgan, Nathaniel P. Butterworth, Folkmar Hauff, David T. Sandwell, Wilfried Jokat, Jan R. Wijbrans, Peter Stoffers. Deformation-related volcanism in the Pacific Ocean linked to the Hawaiian–Emperor bend. Nature Geoscience, 2015; DOI: 10.1038/ngeo2416

Note: The above story is based on materials provided by University of Sydney.

Perspectives on the Nepal earthquake

April 29, 2015

Preliminary landslide susceptibility map created by Dr Tom Robinson (University of Canterbury). Susceptibility ranges from 0 to 1 with higher numbers indicating a greater chance of landslides occurring. Earthquake epicentre shown with a star. Langtang Valley is circled.

As the death toll continues to rise in Nepal, Senior Lecturer Dr Ian Willis, and PhD student Evan Miles, from the Scott Polar Research Institute contemplate the fate of people in a remote part of the country, where they have been doing research for the past two years.

As many agencies are now reporting, the death toll associated with the 7.9 magnitude earthquake that hit Nepal on Saturday is likely to rise considerably over the coming days and weeks. On Tuesday it stands at over 4,000 but the Nepalese Prime Minister, Sushil Koirala, announced that it might reach 10,000. The UN declared that 8 million people have been affected, with 1.4 million people urgently needing aid.

The full scale of the damage will become clear as contact is made with remote settlements away from the capital, which are now largely cut off from communication and supply. In Kathmandu and other urban centres, the greatest cause of injury and death was collapsing buildings.

But in more isolated, mountainous regions, further problems arose from the shaking ground triggering a range of natural hazards. One such region is the Langtang Valley, 60km north of Kathmandu, where we have been doing research for the last two years.

A recent analysis shows the entire valley would have been particularly susceptible to landslides following the earthquake due to its proximity to the epicentre and the topography of the mountain slopes there.

We are exceptionally fortunate not to have been in the area when the earthquake struck. We were in Kathmandu for an International Glaciology Society Symposium in early March.

One of us (Ian Willis) stayed on to do glaciological fieldwork with two other scientists from Cambridge (Dr Hamish Pritchard and PhD student Mike McCarthy) towards the top of the Langtang Valley, returning very recently.

In fact Hamish Pritchard is still in Kathmandu, safe and now helping the UN effort.

The other of us (Evan Miles) was due to fly to Nepal on Sunday and walk to the head of the Langtang Valley this week, but of course his trip was cancelled.

For the past two years, we have been working there with science colleagues from Switzerland, Netherlands and Nepal and aided by a professional Nepali team of guides, porters and cooks.

The overall aim of the research project has been to better understand the climate of the region, and to investigate how the changing climate is affecting the glaciers and the discharge of water in the streams.

This is of huge societal importance, as the people of the valley rely on ground and stream water for their livelihoods – drinking, washing and irrigating crops.

In addition, a small hydro-electric plant was due to be built later this year at the uppermost village in the valley, Kyanjin Gompa, but this will presumably now be put on hold.

Our specific work focuses on improving knowledge about the glaciers of the region. And it is while undertaking our research that we have come to appreciate many of the natural hazards that occur in the area.

Many of the glaciers in Nepal and elsewhere across High Mountain Asia are covered by debris, which may inhibit the rate of ice melting underneath.

The debris gets onto the glaciers through rockfalls, debris avalanches and mudflows. These are continuous processes, but would have been orders of magnitude more severe during the recent earthquake than anything we ever saw.

Many of the glaciers across the Himalaya and surrounding mountains are nourished by snow avalanches.

Again, these occur regularly (we have both been caught in snow avalanches sweeping down the glacier we work on) but the energy they contain is typically dissipated by the time they reach the valley bottoms.

As the recent footage from the Everest region shows, however, snow avalanches can be particularly large and devastating when triggered by an earthquake.

Finally, many glaciers in the region are associated with lakes – these form on the glacier surface where they are dammed by ice, or in front of the glacier where they are blocked by moraines (large ridges of sediment ‘bulldozed’ by a formerly more extensive glacier).

The rapid draining of such lakes provides another hazard, causing floods or mudflows to downstream regions. Again, the flooding and mudflows associated with lake dams rupturing is likely to have had a significant impact during the recent earthquake.

Our field research is on hold at present while we wait to hear the fate of the people of the Langtang Valley and other remote regions of Nepal. But initial reports from Langtang sound very bleak. Eye witness accounts state “From where we were, there was nothing you could see. All the villages were gone,” and “the whole valley has been destroyed”.

Helicopter-based photographs seem to confirm that Langtang village has been wiped out by a large landslide. We are busy scouring satellite data to identify zones of the worst impact, but Nepal has been shrouded in heavy clouds and rain since the earthquake inhibiting our efforts.

DEC Nepal Earthquake Appeal

Video

Note : The above story is based on materials provided by University of Cambridge.

Landslides, mudslides likely to remain a significant threat in Nepal for months

April 29, 2015

Map of landslide and landslide dam hazard potential. Credit: Marin Clark, Nathan Niemi and Sean Gallen

The threat of landslides and mudslides remains high across much of Nepal’s high country, and the risk is likely to increase when the monsoon rains arrive this summer, according to a University of Michigan researcher.

U-M geomorphologist Marin Clark and two colleagues have assessed the landslide hazard in Nepal following Saturday’s magnitude-7.8 earthquake. They looked for locations where landslides likely occurred during the earthquake, as well as places that are at high risk in the coming weeks and months.

The analysis revealed tens of thousands of locations at high risk, Clark said.

“The majority of them, we expect, have already happened and came down all at once with the shaking on Saturday,” she said. “But there will still be slopes that have not yet failed but were weakened. So there will be a continued risk during aftershocks and with the recent rainfall, and again when the monsoon rains arrive this summer.”

Information from the U-M-led study has been shared with the U.S Geological Survey, NASA, the U.S. Agency for International Development and other responding agencies. It is being used help prioritize both satellite observations and the analysis of data from those satellites, said Clark, an associate professor in the U-M Department of Earth and Environmental Sciences.

“The satellites looked first at places where lots of people live, including Kathmandu and the foothills areas to the south,” Clark said. “Those areas do not look significantly impacted by landsliding, but we’re worried about the high country,” she said.

The region at highest risk for landslides and mudslides is the mountainous area along the Nepal-Tibet border, north of Kathmandu and west of Mount Everest, directly above the fault rupture. The highest-risk zone is at elevations above 8,200 feet in a region that covers 17,550 square miles, which is roughly twice the size of Massachusetts.

Cloud cover has blocked observation of much of that region since Saturday’s earthquake. But news stories and social media reports of landslides in Nepal’s Gorka District and Langtang Valley are consistent with the Clark team’s assessment, which showed that those areas are at high risk, she said.

Remote villages are scattered throughout the high-risk zone, which also contains the main highway that connects Kathmandu and Tibet. The area is popular with trekkers and mountaineers, as well.

“Many small Nepalese villages throughout this region have likely been cut off from the rescue operation,” Clark said. “This is also high season for trekking and mountaineering, so I expect there are a large number of foreign tourists there, as well.”

The Clark team’s assessment of the landslide risk was based on a computer analysis that looked at earthquake shaking, slope steepness and the strength of various rock types.

Their initial analysis was completed Saturday afternoon and was shared with the U.S. Geological Survey and other agencies on Saturday evening. It was revised Sunday morning and distributed through the National Earthquake Hazards Reduction Program on Sunday afternoon.

More than 200,000 landslides occurred following a magnitude-7.9 earthquake in a mountainous region of Sichuan Province, China, in 2008, according to Clark. Many of those landslides blocked roads, which slowed response and recovery efforts. The final death toll for that quake was about 70,000.

Landsliding is a general term for slowly to very rapidly descending rock and debris. A mudslide or mudflow is a fluid mix of mud and debris that moves down a slope.

Landslides in mountainous regions can also block river valleys, creating a significant flooding hazard. Water builds up behind those dam-like structures, creating the potential for catastrophic flooding if the dams are overtopped and then fail.

“With the satellite images, we’ll be looking first at the highest-risk landslide areas that are close to big rivers,” Clark said. “Those locations are high priorities.”

Clark’s collaborators on the landslide hazard assessment are U-M’s Nathan Niemi and Sean Gallen, a former U-M postdoctoral researcher under Clark who recently accepted a position at ETH Zurich in Switzerland.

Note: The above story is based on materials provided by University of Michigan.

Engineering a better future for the Mississippi Delta

April 29, 2015

This image shows Mississippi River Delta, 2001. Credit: Image courtesy NASA

River deltas, low-lying landforms that host critical and diverse ecosystems as well as high concentrations of human population, face an uncertain future. Even as some deltas experience decreased sediment supply from damming, others will see increased sediment discharge from land-use changes. Accurate estimates of the current rate of subsidence in the Mississippi Delta (southern USA) are important for planning wetland restoration and predictions of storm surge flooding.
Parts of coastal Louisiana (southern USA) are undergoing accelerated land loss due to the combined effects of sea-level rise and land subsidence. In the Mississippi Delta, where rates of land loss are especially severe, subsidence of the land surface reflects natural processes, such as sediment compaction and crustal loading, but this is exacerbated by anthropogenic withdrawal of fluids (water, oil, natural gas).

In this study for Geology, Makan Karegar and colleagues use precise Global Positioning System (GPS) data to measure subsidence rates of the Mississippi Delta. They also use tide gauge records to better understand the relationship between subsidence and sea-level rise in southern Louisiana.

The authors show that while the majority of the delta is relatively stable, parts of the delta may not be viable in the long term. The southern portion of the delta continues to experience high rates of subsidence (5 to 6 mm per year). The current rate of relative sea-level rise (the combined effect of land subsidence and sea-level rise) along parts of the coastal delta is nearly 8 to 9 mm per year.

Given stable sea level and sediment deposition, a delta will tend toward an equilibrium state where subsidence is more or less balanced by sediment deposition. In the Mississippi River system, however, a series of dams on various upstream tributaries have reduced sediment supply to the delta, while levees on the lower part of the river have artificially channelized the flow, forcing sediments to be deposited beyond the delta in the deeper Gulf of Mexico.

The data presented by Karegar and colleagues have implications for land reclamation and wetland restoration in the region. Mitigation efforts may include river diversion to encourage resedimentation, and pumping of offshore sands to restore barrier islands.

Reference:
M. A. Karegar, T. H. Dixon, R. Malservisi. A three-dimensional surface velocity field for the Mississippi Delta: Implications for coastal restoration and flood potential. Geology, 2015; DOI: 10.1130/G36598.1

Note: The above story is based on materials provided by Geological Society of America.

DNA suggests all early eskimos migrated from Alaska’s North Slope

April 29, 2015

Landsat 7 false-color image of the North Slope. Credit: NASA

Genetic testing of Iñupiat people currently living in Alaska’s North Slope is helping Northwestern University scientists fill in the blanks on questions about the migration patterns and ancestral pool of the people who populated the North American Arctic over the last 5,000 years.

“This is the first evidence that genetically ties all of the Iñupiat and Inuit populations from Alaska, Canada and Greenland back to the Alaskan North Slope,” said Northwestern’s M. Geoffrey Hayes, senior author of the new study to be published April 29, 2015, in the American Journal of Physical Anthropology.

In this study, all mitochondrial DNA haplogroups previously found in the ancient remains of Neo- and Paleo-Eskimos and living Inuit peoples from across the North American Arctic were found within the people living in North Slope villages.

These findings support the archaeological model that the “peopling of the eastern Arctic” began in the North Slope, in an eastward migration from Alaska to Greenland. It also provides new evidence to support the hypothesis that there were two major migrations to the east from the North Slope at two different times in history.

“There has never been a clear biological link found in the DNA of the Paleo-Eskimos, the first people to spread from Alaska into the eastern North American arctic, and the DNA of Neo-Eskimos, a more technologically sophisticated group that later spread very quickly from Alaska and the Bering Strait region to Greenland and seemed to replace the Paleo-Eskimo,” Hayes said.

“Our study suggests that the Alaskan North Slope serves as the homeland for both of those groups, during two different migrations. We found DNA haplogroups of both ancient Paleo-Eskimos and Neo-Eskimos in Iñupiat people living in the North Slope today.”

Hayes is an assistant professor of endocrinology at Northwestern University Feinberg School of Medicine and an assistant professor of anthropology at Northwestern’s Weinberg College of Arts and Sciences. He has been studying population genetics of the Arctic for more than a decade.

At the request of Iñupiat elders from Barrow, Alaska, who are interested in using scientific methods to learn more about the history of their people, Hayes and a team of scientists extracted DNA from saliva samples given by 151 volunteers living in eight different North Slope communities. This is the first genetic study of modern-day Iñupiat people.

For this paper, the scientists sequenced and analyzed only mitochondrial DNA. Mitochondrial DNA is passed down from mother to child, with few changes from generation to generation.

Ninety-eight percent of the maternal linages in this group were of Arctic descent. The scientists found all known Arctic-specific haplogroups present in these North Slope communities. The haplogroups are: A2a, A2b, D4b1a and D2.

D2 is the known haplogroup of ancient Paleo-Eskimos. Until this study D2 had only been found in the remains of ancient Paleo-Eskimos.

D4b1a is a known haplogroup of the ancient Neo-Eskimos, the much more technologically sophisticated group that came after the Paleo-Eskimos and seemed to replace them and populate a large part of the Arctic in a short amount of time.

“We think the presence of these two haplotypes in villages of the North Slope means that the Paleo-Eskimos and the Neo-Eskimos were both ancestors of the contemporary Iñupiat people,” said Jennifer A. Raff, first author of the study and a post-doctoral fellow in Hayes’ lab at the Feinberg School when the research was being done. “We will be exploring these connections in the future with additional genetic markers.”

Another haplogroup that surfaced in this study was C4. This is typically only seen in Native Americans much farther south. Its geographic distribution suggests that it might have been one of the haplogroups carried by the earliest peoples to enter the Americas. The researchers think it could be seen in the North Slope because of recent marriages between Athapascan and Iñupiat families or because it is a remnant of a much more ancient contact between these groups.

One more surprise in this study was evidence there may have been some migrations of Greenlandic Inuit back to the Alaska North Slope. The scientists plan to explore this in the future with additional genetic markers, too.

This work is part of the Genetics of the Alaskan North Slope project, funded by a grant from the National Science Foundation’s Office of Polar Programs. The goal of the project is to reconstruct the human genetic history along the North Slope. The scientists hope the project will be a model for research partnerships between geneticists and indigenous peoples.

While this study revealed exciting new evidence about the history and prehistory of Iñupiat women, it also confirms local history about the close-knit ties of the North Slope villages.

“We found that there were many lineages shared between villages along the coast, suggesting that women traveled frequently between these communities,” Hayes said. “In fact, when we compared the genetic composition of all the communities in the North Slope, we found that they were all so closely related that they could be considered one single population. This fits well with what the elders and other community members have told us about Iñupiat history.”

Future work will analyze genetic markers on the Y-chromosomes from men in the North Slope, taking a closer look at the population history of men, as well as how contact with outsiders in the 19th century affected the Iñupiat peoples.

Note : The above story is based on materials provided by Northwestern University.

Ancient connection between the Americas enhanced extreme biodiversity

April 29, 2015

Scientists think that salamanders from North America arrived in South America before the accepted date for the closure of the Isthmian land bridge 3 million years ago, supporting Bacon et al’s assertion that the Isthmus closed at an earlier date. Credit: STRI Archives

Species exchange between North and South America created one of the most biologically diverse regions on Earth. A new study by Smithsonian scientists and colleagues published this week in the Proceedings of the National Academy of Sciences shows that species migrations across the Isthmus of Panama began about 20 million years ago, some six times earlier than commonly assumed. These biological results corroborate advances in geology, rejecting the long-held assumption that the Isthmus is only about 3 million years old.
“Even organisms that need very specific conditions to survive, such as salamanders and freshwater fishes, crossed the Isthmus of Panama over 6 million years ago,” said lead author, Christine Bacon, former post-doctoral fellow in staff scientist Carlos Jaramillo’s group at the Smithsonian Tropical Research Institute. “These early migrations impact our understanding of how and when biodiversity in the Americas took shape.”

The Isthmus of Panama, which links North and South America, plays a crucial role in the planet’s atmospheric and oceanic circulation, climate and biodiversity. Despite its importance across multiple disciplines, the timing of the formation and emergence of the Isthmus and the effect it had on those continents’ biodiversity is controversial.

In the new study, Bacon, now at the University of Gothenburg in Sweden, examines a large number of molecular studies and fossils, including land and aquatic organisms.

Models based on molecular genetic data indicate that rather than one great migration following a set closure time, there were several periods in which animals and plants moved across the intercontinental land bridge. There are shifts in the rate of movement of animal fossils moving from North America to South America at 23 million and within the past 10 million years.

Authors also compare the proportion of immigrants in each direction to sea level and global mean temperature, showing that migrations may have coincided with low sea levels.

A known date for the rise of the Isthmus is important to evolutionary biologists who want to understand how species of marine organisms diverged and when species of terrestrial organisms moved from one continent to another. The date is also critical in understanding ancient climate change patterns. The 3 million year date was established by the Panama Paleontology Project, headed by Jeremy Jackson and Anthony Coates, also at the Smithsonian Tropical Research Institute.

Reference:
Bacon, C.D., D. Silvestro, C.A. Jaramillo, B. Tilston Smith, P. Chakrabarty, A. Antonelli. Biological evidence shows earlier emergence of the Isthmus of Panama. PNAS, 2015 DOI: 10.1073/pnas.1423853112

Note: The above story is based on materials provided by Smithsonian Tropical Research Institute.

Researchers find evidence of groundwater in Antarctica’s Dry Valleys

April 29, 2015

A helicopter flies the AEM sensor over Blood Falls and the Taylor Glacier, Antarctica Photo credit: L. Jansan

Using a novel, helicopter-borne sensor to penetrate below the surface of large swathes of terrain, a team of researchers supported by the National Science Foundation, or NSF, has gathered compelling evidence that beneath the Antarctica ice-free McMurdo Dry Valleys lies a salty aquifer that may support previously unknown microbial ecosystems and retain evidence of ancient climate change.

The team, which includes LSU hydrogeologist Peter Doran and researchers from the University of Tennessee; University of California-Santa Cruz; Dartmouth College; University of Illinois at Chicago; University of Wisconsin; Aarhus University in Denmark; and Sorbonne Universités, UPMC University in France, found that brines, or salty water, form extensive aquifers below glaciers, lakes and within permanently frozen soils. Their discovery will be featured in the April 28 edition of the open-access journal Nature Communications.

“These unfrozen materials appear to be relics of past surface ecosystems, and our findings provide compelling evidence that they now provide deep subsurface habitats for microbial life despite extreme environmental conditions,” said the study’s lead author Jill Mikucki, an assistant professor of microbiology at the University of Tennessee Knoxville. “We believe the application of novel below-ground visualization technologies can not only reveal hidden microbial habitats, but can also provide insight on glacial dynamics and how Antarctica responds to climate change.”

In addition to providing answers about the biological adaptations of previously unknown ecosystems that persist in the extreme cold and dark of the Antarctic winter, the new information could also help scientists understand whether similar conditions might exist elsewhere in the solar system, specifically beneath the surface of Mars, which has many similarities to the dry valleys.

“Over billions of years of evolution, microbes seem to have adapted to conditions in almost all surface and near-surface environments on Earth. Tiny pore spaces filled with hyper-saline brine staying liquid down to -15 Celsius, or 5 degrees Fahrenheit, may pose one of the greatest challenges to microbes,” said Slawek Tulacyzk, a glaciologist and coauthor at the University of California, Santa Cruz. “Our electromagnetic data indicates that margins of Antarctica may shelter a vast microbial habitat, in which limits of life are tested by difficult physical and chemical conditions.”

The team also found evidence that brines flow towards the Antarctic coast from roughly 11 miles inland, eventually discharging into the Southern Ocean. It is possible that nutrients from microbial weathering in these deep brines are released, effecting near-shore biological productivity. However, the vast majority of Antarctica’s coastal margins remain unexplored. This new survey highlights the importance of these sensitive interfaces.

The Division of Polar Programs in NSF’s Geoscience’s Directorate supported the AEM sensor project through a collaborative award to Mikucki, Tulacyzk and Ross Virginia, a biogeochemist at Dartmouth College. The division manages the U.S. Antarctic Program, through which it coordinates all U.S. scientific research on the Southernmost Continent and provides the logistical support to that research.

The researchers used a transient electromagnetic AEM sensor called SkyTEM, mounted to a helicopter, to produce extensive imagery of the subsurface of the coldest, driest desert on our planet, the McMurdo Dry Valleys. Using a helicopter to make the observations allowed large areas of rugged terrain to be efficiently surveyed.

The results shed new light on the history and evolution of the dry valley landscape, which, uniquely in the Antarctic is ice-free and which during the height of the southern summer has free-flowing rivers and streams. The dry valleys are also home to briny lakes at the surface and beneath at least one of the glaciers that intrude into the Valleys.

“Prior to this discovery, we considered the lakes to all be isolated from one another and the ocean, but this new data suggests that there is a connection between the lakes and the ocean, which is very interesting and potentially a game changer in how we view the geochemistry and history of the lakes,” said Doran, LSU professor of geology & geophysics and John Franks Endowed Chair.

Doran, the first to hold the John Franks Endowed Chair in geology & geophysics, is a natural fit for this research team in that the ground water system examined in this study is closely associated with the perennially ice covered lakes in the region that he has been studying for more than 20 years.

Doran joined the research team after the data was collected and assisted with the data interpretation.

“The first phase of this research was a proof of concept study and we definitely proved the concept,” he said, adding that the team is in the process of writing a new proposal to NSF to continue their work.

Overall, the dry valleys ecosystem — cold, vegetation-free and home only to microscopic animal and plant life — resembles, during the Antarctic summer, conditions on the surface on Mars.

In addition to many other studies, the dry valleys are home to projects that are investigating how climate has changed over geologic time.

“This project is studying the past and present climate to, in part, understand how climate change in the future will affect biodiversity and ecosystem processes,” said Virginia. “This fantastic new view beneath the surface will help us sort out competing ideas and theories about how the dry valleys have changed with time and how this history influences what we see today.”

The AEM sensor, which was developed at Aarhus University in Denmark, was flown over the Taylor Glacier, one of the best-studied glaciers in the world, in November 2011. The glacier has a unique feature known as Blood Falls, where iron-rich brine from the subsurface is released at the front of the glacier. Blood Falls is known to harbor an active microbial community, where organisms use iron and sulfur compounds for energy and growth and in the process facilitate rock weathering.

The AEM team believes that the newly discovered brines harbor similar microbial communities persisting in the deep, cold dark aquifers. AEM instrumentation lead Esben Auken has flown the sensor all over the world, but this was the first time they tackled Antarctica.

“Antarctica is by far the most challenging place we have been.” Auken said. “It was all worth it when we saw the raw data as it was offloaded from the helicopter. It clearly showed we were on to some extraordinary results, which no one had been able to produce before. We were excited because we knew this would change the way scientists in the future would view the hydrological cycle in the dry valleys. For us, the project was the result of many years of developing the best mapping technology in the world, and now we were able to collaborate with scientists who had worked in the Antarctic environment for decades and were willing to take the risk of letting us prove this could be done with success.”

Video

Note : The above story is based on materials provided by Louisiana State University.

Road cracks after Nepal earthquake

April 27, 2015

Bizarre ‘platypus’ dinosaur discovered

April 27, 2015

Artist’s interpretation of Chilesaurus diegosuareziis. Credit: Gabriel Lío

Although closely related to the notorious carnivore Tyrannosaurus rex, a new lineage of dinosaur discovered in Chile is proving to be an evolutionary jigsaw puzzle, as it preferred to graze upon plants.

Palaeontologists are referring to Chilesaurus diegosuarezi as a ‘platypus’ dinosaur because of its bizarre combination of characters that resemble different dinosaur groups. For example, Chilesaurus boasted a proportionally small skull, hands with two fingers like Tyrannosaurus rex and feet more akin to primitive long-neck dinosaurs.

Chilesaurus diegosuarezi is nested within the theropod group of dinosaurs, the dinosaurian group that gathers the famous meat eaters Velociraptor, Carnotaurus and Tyrannosaurus, and from which birds today evolved. The presence of herbivorous theropods was up until now only known in close relatives of birds, but Chilesaurus shows that a meat-free diet was acquired much earlier than thought.

Chilesaurus diegosuarezi is named after the country where it was collected, as well as honouring Diego Suárez, the seven year old boy who discovered the bones. He discovered the fossil remains of this creature at the Toqui Formation in Aysén, south of Chilean Patagonia, in rocks deposited at the end of the Jurassic Period, approximately 145 million years ago.

Diego was in the region with his parents, Chilean geologists Manuel Suarez and Rita de la Cruz, who were studying rocks in the Chilean Patagonia, with the aim to better understand the formation of the Andes mountain range. Diego stumbled across the fossils while him and his sister, Macarena, were looking for decorative stones.

Due to Chilesaurus’ unusual combination of characters, it was initially thought that Diego had uncovered several species. However, since Diego’s find, more than a dozen Chilesaurus specimens have been excavated, including four complete skeletons — a first for the Jurassic Period in Chile — and they demonstrate that this dinosaur certainly combined a variety of unique anatomical traits.

Most of the specimens are the size of a turkey, but some isolated bones reveal that the maximum size of Chilesaurus was around three metres long. Chilean and Argentinian palaeontologists from institutions including the University of Birmingham, along with Diego’s parents, have been studying these skeletons, with the findings published in full in Nature on April 27th.

Other features present in very different groups of dinosaurs Chilesaurus adopted were robust forelimbs similar to Jurassic theropods such as Allosaurus, although its hands were provided with two blunt fingers, unlike the sharp claws of fellow theropod Velociraptor. Chilesaurus’ pelvic girdle resembles that of the ornithischian dinosaurs, whereas it is actually classified in the other basic dinosaur division — Saurischia.

The different parts of the body of Chilesaurus were adapted to a particular diet and way of life, which was similar to other groups of dinosaurs. As a result of these similar habits, different regions of the body of Chilesaurus evolved resembling those present in other, unrelated groups of dinosaurs, which is a phenomenon called evolutionary convergence.

Chilesaurus represents one of the most extreme cases of mosaic convergent evolution recorded in the history of life. For example, the teeth of Chilesaurus are very similar to those of primitive long-neck dinosaurs because they were selected over millions of years as a result of a similar diet between these two lineages of dinosaurs.

Martín Ezcurra, Researcher, School of Geography, Earth and Environmental Sciences, University of Birmingham said: ‘Chilesaurus can be considered a ‘platypus’ dinosaur because different parts of its body resemble those of other dinosaur groups due to mosaic convergent evolution. In this process, a region or regions of an organism resemble others of unrelated species because of a similar mode of life and evolutionary pressures. Chilesaurus provides a good example of how evolution works in deep time and it is one of the most interesting cases of convergent evolution documented in the history of life.

‘Chilesaurus shows how much data is still completely unknown about the early diversification of major dinosaur groups. This study will force palaeontologists to take more care in the future in the identification of fragmentary or isolated dinosaur bones. It comes as false relationship evidence may arise because of cases of convergent evolution, such as that present in Chilesaurus.’

Dr. Fernando Novas, Bernardino Rivadavia Natural Sciences Museum, Buenos Aires, Argentina, led the research on Chilesaurus and said: ‘Chilesaurus is the first complete dinosaur from the Jurassic Period found in Chile and represents one of the most complete and anatomically correct documented theropod dinosaurs from the southern hemisphere. Although plant-eating theropods have been recorded in North America and Asia, this is the first time a theropod with this characteristic has been found in a southern landmass.

Chilesaurus was an odd plant-eating dinosaur only to be found in Chile. However, the recurrent discovery in beds of the Toqui Formation of its bones and skeletons clearly demonstrates that Chilesaurus was, by far, the most abundant dinosaur in southwest Patagonia 145 million years ago.’

Reference:
Fernando E. Novas, Leonardo Salgado, Manuel Suárez, Federico L. Agnolín, Martín D. Ezcurra, Nicolás R. Chimento, Rita de la Cruz, Marcelo P. Isasi, Alexander O. Vargas, David Rubilar-Rogers. An enigmatic plant-eating theropod from the Late Jurassic period of Chile. Nature, 2015; DOI: 10.1038/nature14307

Note: The above story is based on materials provided by University of Birmingham.

Tidal tugs on Teflon faults drive slow-slipping earthquakes

April 27, 2015

Slow earthquakes happen between the hazardous locked zone and the viscous portion that slips silently. They are found on subduction zones, like Cascadia’s, where a heavy ocean plate, in this case the Juan de Fuca Plate, sinks below a lighter continental plate. Credit: Univ. of Washington

Unknown to most people, the Pacific Northwest experiences a magnitude-6.6 earthquake about once a year. The reason nobody notices is that the movement happens slowly and deep underground, in a part of the fault whose behavior, known as slow-slip, was only recently discovered.

A University of Washington seismologist who studies slow-slip quakes has looked at how they respond to tidal forces from celestial bodies and used the result to make a first direct calculation of friction deep on the fault. Though these events occur much deeper and on a different type of fault than the recent catastrophe in Nepal, the findings could improve general understanding of when and how faults break.

The new study, published online April 27 in Nature Geoscience, shows that the gravitational pull of the sun and the moon affect the Cascadia fault a few days after it has started slipping. The timing of movement suggests that the friction at this depth on the fault is only 0.1, roughly that of two pieces of lubricated metal.

“I was able to tease out the effect of friction and found that it is not the friction of normal rocks in the lab — it’s much lower,” said author Heidi Houston, a UW professor of Earth and space sciences. “It’s closer to Teflon than to sandpaper.”

The surprising results of the new study could help to better model the physics of these systems, and they could even tell us something about the frictional forces in the locked portion of the fault where hazardous earthquakes occur.

The research looked at six recent slow-slip events along the Cascadia subduction zone, one of the best-studied places for these enigmatic slow quakes. The slow quakes are accompanied by tremors, weak seismic vibrations previously thought to be random noise. The tremors begin every 12 to 14 months below Puget Sound, Washington, and then travel north and south at about 5 miles (8 kilometers) per day for several weeks, affecting each section of the fault for about five days.

The paper looks at how the gravitational pull of the sun and moon, which slightly deform the Earth and oceans, affect forces along, across and inside the fault, and what that means for the slow-slip seismic activity more than 20 miles (35 kilometers) underground.

Results show that on the first day of tremors, the tidal forces don’t matter much. But starting at about 1 1/2 days — when Houston thinks minerals that had been deposited from the surrounding fluid and that held the fault together may have broken — the additional pull of the tides does have an effect.

“Three days after the slipping has begun, the fault is very sensitive to the tides, and it almost slips only when the tides are encouraging it,” Houston said.

“It implies that something is changing on the fault plane over those five days.”

By averaging across many sections of the fault, and over all six events, she found that the amount of the tremor increases exponentially with increasing tidal force.

Regular fast earthquakes are also very slightly affected by the tides, but they are overwhelmed by other forces and the effect is almost too small to detect.

There is no need for worry, Houston says — even when celestial bodies line up to generate the biggest king tides, the effect would only rarely be enough to actually trigger a slow-slip quake, much less a regular earthquake. But it does tell us something about the physics of a crucial process that can’t be easily studied in the lab.

“We want to understand the physics of what is happening, to understand and predict how the fault is storing stress, and how it’s going to relieve stress,” Houston said. “Friction is a big piece of that. And it turns out that this part of the fault is much slipperier than previously thought.”

Slow-slip earthquakes relieve stress right where they slipped, but the movement actually places more stress on neighboring parts of the fault, including the so-called locked zone, where a rupture can cause the most damaging type of earthquakes.

In Cascadia’s slow-slip events the fault will move about an inch (3 centimeters) over several days, with different parts of the fault moving at different times. When the shallower “locked zone” ruptures, by contrast, a large section of the fault can lurch over 60 feet (18 meters) in minutes. When this occurs, as it does about every 500 years in a magnitude 9 on the Cascadia subduction zone, it generates strong damaging seismic waves in the Earth’s crust.

Still unknown is how slow-slip events are related to the more damaging quakes. A shallower slow-slip event was detected in the weeks before the deadly 2011 Tohoku earthquake and tsunami, on a fault like Cascadia’s where an ocean plate plunges below a continental plate.

“Understanding slow slip and tremor could give us some way to monitor what is happening in the shallower, locked part of the fault,” Houston said. “Geophysicists started with the picture of just a flat plane of sandpaper, but that picture is evolving.”

Reference:
Low friction and fault weakening revealed by rising sensitivity of tremor to tidal stress, Nature Geoscience (2015) DOI: 10.1038/ngeo2419

Note : The above story is based on materials provided by University of Washington.

Calbuco volcano – evacuations and air-traffic disruption follow eruption

April 27, 2015

Eruption of the Calbuco volcano, seen from Puerto Montt. Credit: EPA/Francisco Negroni

The Calbuco volcano, a 2,000 metre peak in southern Chile, sent a column of ash about 15km skywards twice on the night of April 22 and early the following morning. As the risk of deadly flows of ash and hot air was immediate, a 20km radius evacuation zone was declared.
The event was spectacularly visible from Puerto Montt, a city of nearly 200,000 inhabitants, only 30 km away. It seems to have begun within barely five hours of warning signs being first detected by local seismometers.

There two big eruptions over seven hours caused ash to fall in the Argentinian town of San Martin de los Andes, nearly 200km north-east of the volcano. Further eruptions are possible, although the likelihood of this decreases as time passes.

Eruptions like these are particularly significant because they have the potential to produce pyroclastic flows, which are fast-moving ground-hugging currents of ash and hot air, triggered when a rising ash column collapses. These are deadly – and the 20km radius evacuation zone wisely remains in place in case the volcano (quiet during most of April 24) wakes up again. For example, pyroclastic flows at the Indonesian volcano Sinabung killed at least 16 people in February last year, who had strayed back inside the local evacuation zone.

Less immediately deadly is the fall-out that settles from the high-altitude ash cloud that slowly disperses downwind. This is a respiratory hazard and can also kill vegetation and contaminate water supplies. After an eruption has ceased, ash that has settled to the ground will pose a risk of volcanic mudflows (widely known by their Indonesian name “lahars”) that can choke water-courses and destroy bridges.

Calbuco is about 90km south of the Puyehue-Cordon Caulle volcano, which erupted in June 2011 spreading airborne ash around the globe, leading to airspace closures in Australia. That eruption lasted for months, and produced a high ash column for more than a week. Calbuco’s current eruption seems unlikely to persist so long but already it has disrupted local air travel.

Volcanic ash is dangerous to aircraft and the Buenos Aires Volcanic Ash Advisory Centre (VAAC) this week issued a warning of airborne ash up to 40,000ft high across Chile and Argentina. The cloud is expected to disperse over Argentina, as as it is no longer being fed by a continuing eruption anyone hoping to fly in or out of Australia has little need to worry.

These days the rules about flying in volcanic ash are less stringent than they were during the 2010 eruption of Iceland’s Eyjafjallajökull volcano. When that began, the rule was if there was any ash at all, it was forbidden to fly through it. Nowadays it is agreed that a small amount of ash can be tolerated for short periods. Unfortunately it is hard to be sure of the density of airborne ash, so it is best to err on the side of caution.

Calbuco had been quiet since a four-hour eruption on August 26 1972, except for an episode of gas emission from fumaroles on 12 August 1996. One of the largest historical eruptions in Chile took place here in 1893-4, throwing 30cm bombs as far as 8km from the summit crater.

These and other volcanoes in the Andes are present as a result of plate tectonic processes, which also cause earthquakes in the region. The floor of the Pacific ocean (actually the Nazca Plate) is being pushed below South America which leads to melting at depth which forces magma upwards to feed the volcanoes. Because seawater has been transported into the melting zone, the magma contains gases such as water vapour and carbon dioxide, and the violent expansion of gas bubbles is what makes eruptions at these volcanoes so explosive.

Video

Ash fallout from Calbuco in San Martin de los Andes.

Video from Puerto Montt showing the 22/23 April eruption of Calbuco.

Note : The above story is based on materials provided by The Conversation.
This story is published courtesy of The Conversation (under Creative Commons-Attribution/No derivatives).

Chemistry of seabed’s hot vents could explain emergence of life

April 27, 2015

Image courtesy of MARUM, University of Bremen and NOAA-Pacific Marine Environmental Laboratory.

Hot vents on the seabed could have spontaneously produced the organic molecules necessary for life, according to new research by UCL chemists. The study shows how the surfaces of mineral particles inside hydrothermal vents have similar chemical properties to enzymes, the biological molecules that govern chemical reactions in living organisms. This means that vents are able to create simple carbon-based molecules, such as methanol and formic acid, out of the dissolved CO2 in the water.

The discovery, published in the journal Chemical Communications, explains how some of the key building blocks for organic chemistry were already being formed in nature before life emerged — and may have played a role in the emergence of the first life forms. It also has potential practical applications, showing how products such as plastics and fuels could be synthesised from CO2 rather than oil.

“There is a lot of speculation that hydrothermal vents could be the location where life on Earth began,” says Nora de Leeuw, who heads the team. “There is a lot of CO2 dissolved in the water, which could provide the carbon that the chemistry of living organisms is based on, and there is plenty of energy, because the water is hot and turbulent. What our research proves is that these vents also have the chemical properties that encourage these molecules to recombine into molecules usually associated with living organisms.”

The team combined laboratory experiments with supercomputer simulations to investigate the conditions under which the mineral particles would catalyse the conversion of CO2 into organic molecules. The experiments replicated the conditions present in deep sea vents, where hot and slightly alkaline water rich in dissolved CO2 passes over the mineral greigite (Fe3S4), located on the inside surfaces of the vents. These experiments hinted at the chemical processes that were underway. The simulations, which were run on UCL’s Legion supercomputer and HECToR (the UK national supercomputing service), provided a molecule-by-molecule view of how the CO2 and greigite interacted, helping to make sense of what was being observed in the experiments. The computing power and programming expertise to accurately simulate the behaviour of individual molecules in this way has only become available in the past decade.

“We found that the surfaces and crystal structures inside these vents act as catalysts, encouraging chemical changes in the material that settles on them,” says Nathan Hollingsworth, a co-author of the study. “They behave much like enzymes do in living organisms, breaking down the bonds between carbon and oxygen atoms. This lets them combine with water to produce formic acid, acetic acid, methanol and pyruvic acid. Once you have simple carbon-based chemicals such as these, it opens the door to more complex carbon-based chemistry.”

Theories about the emergence of life suggest that increasingly complex carbon-based chemistry led to self-replicating molecules — and, eventually, the appearance of the first cellular life forms. This research shows how one of the first steps in this journey may have occurred. It is proof that simple organic molecules can be synthesised in nature without living organisms being present. It also confirms that hydrothermal vents are a plausible location for at least part of this process to have occurred.

The study could also have a practical applications, as it provides a method for creating carbon-based chemicals out of CO2, without the need for extreme heat or pressure. This could, in the long term, replace oil as the raw material for products such as plastics, fertilisers and fuels.

This study shows, albeit on a very small scale, that such products, which are currently produced from non-renewable raw materials, can be produced by more environmentally friendly means. If the process can be scaled up to commercially viable scales, it would not only save oil, but use up CO2 — a greenhouse gas — as a raw material.

Reference:
A. Roldan, N. Hollingsworth, A. Roffey, H.-U. Islam, J. B. M. Goodall, C. R. A. Catlow, J. A. Darr, W. Bras, G. Sankar, K. B. Holt, G. Hogarth, N. H. de Leeuw. Bio-inspired CO2conversion by iron sulfide catalysts under sustainable conditions. Chem. Commun., 2015; 51 (35): 7501 DOI: 10.1039/C5CC02078F

Note: The above story is based on materials provided by University College London.

Platinum

April 25, 2015

Chemical Formula: Pt
Locality: Most notably from the Urals, Russia and Brazil.
Name Origin: Spanish, platina = “silver.”

Platinum is a chemical element with the chemical symbol Pt and an atomic number of 78. It is a dense, malleable, ductile, highly unreactive, precious, gray-white transition metal. Its name is derived from the Spanish term platina, which is literally translated into “little silver”.Platinum is a member of the platinum group of elements and group 10 of the periodic table of elements. It has six naturally occurring isotopes. It is one of the rarest elements in the Earth’s crust with an average abundance of approximately 5 μg/kg. It occurs in some nickel and copper ores along with some native deposits, mostly in South Africa, which accounts for 80% of the world production. Because of its scarcity in the earth’s crust, only a few hundred tonnes are produced annually, and is therefore highly valuable and is a major precious metal commodity.Platinum is the least reactive metal. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Consequently, platinum is often found chemically uncombined as native platinum. Because it occurs naturally in the alluvial sands of various rivers, it was first used by pre-Columbian South American natives to produce artifacts. It was referenced in European writings as early as 16th century, but it was not until Antonio de Ulloa published a report on a new metal of Colombian origin in 1748 that it became investigated by scientists.

Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewellery. Being a heavy metal, it leads to health issues upon exposure to its salts, but due to its corrosion resistance, it is not as toxic as some metals. Compounds containing platinum, most notably cisplatin, are applied in chemotherapy against certain types of cancer.

Table of Contents

Physical Properties of Platinum

Cleavage: None
Color: Whitish steel gray, Steel gray, Dark gray.
Density: 14 – 22, Average = 18
Diaphaneity: Opaque
Fracture: Hackly – Jagged, torn surfaces, (e.g. fractured metals).
Hardness: 4-4.5 – Between Fluorite and Apatite
Luminescence: Non-fluorescent.
Luster: Metallic
Magnetism: Naturally weak
Streak: grayish white

Photos:

Native Platinum nugget, locality Kondyor mine, Khabarovsk Krai, Russia. Size: 35 × 23 × 14 mm, Collection: M.R.

Map shows content and origins of the geologic basement

April 24, 2015

This is a map showing basement domains according to generalized original crust types. Credit: USGS

A map showing the many different pieces of Earth’s crust that comprise the nation’s geologic basement is now available from the U.S. Geological Survey. This is the first map to portray these pieces, from the most ancient to recent, by the events that influenced their composition, starting with their origin. This product provides a picture of the basement for the U.S., including Alaska, that can help scientists produce regional and national mineral resource assessments, starting with the original metal endowments in source rocks.

“Traditionally, scientists have assessed mineral resources using clues at or near the Earth’s surface to determine what lies below,” said USGS scientist Karen Lund, who led the project. “This map is based on the concept that the age and origins of basement rocks influenced the nature and location of mineral deposits. It offers a framework to examine mineral resources and other geologic aspects of the continent from its building blocks up,” said Lund.

More than 80 pieces of crust have been added to the nation’s basement since the Earth began preserving crust about 3.6 billion years ago. These basement domains had different ages and origins before they became basement rocks, and this map includes these as key factors that determined their compositions and the original metals that may be available for remobilization and concentration into ore deposits. The map further classifies the basement domains according to how and when they became basement, as these events also influence the specific metals and deposit types that might be found in a region.

Users can identify domains potentially containing specific metals or deposit types. They can configure the companion database to show the construction of the U.S. through time. The map also provides a template to correlate regional to national fault and earthquake patterns. The map is also available on a separate site, where users can combine data and overlay known mineral sites or other features on the domains.

Basement rocks are crystalline rocks lying above the mantle and beneath all other rocks and sediments. They are sometimes exposed at the surface, but often they are buried under miles of rock and sediment and can only be mapped over large areas using remote geophysical surveys. This map was compiled using a variety of methods, including data from national-scale gravity and aeromagnetic surveys.

Crustal rocks are modified several times before they become basement, and these transitions alter their composition. Basement rocks are continental crust that has been modified by a wide variety of plate tectonic events involving deformation, metamorphism, deposition, partial melting and magmatism. Ultimately, continental crust forms from pre-existing oceanic crust and overlying sediments that have been thus modified.

It is not only the myriad processes that result in varying basement rock content but also the time when these processes occurred during the Earth’s history. For example, because the Earth has evolved as a planet during its 4.5 billion year history, early deposit types formed when there was less oxygen in the atmosphere and the thin crust was hotter. The ancient domains are now more stable and less likely to be altered by modern processes that could cause metals to migrate. By contrast, basement rocks that formed out of crust that is less than one billion years old have origins that can be interpreted according to the present-day rates and scales of plate tectonic processes that reflect a more mature planet with a thicker crust.

By incorporating ancient to modern processes, this map offers a more complete and consistent portrait of the nation’s geologic basement than previous maps and presents a nationwide concept of basement for future broad-scale mineral resource assessments and other geologic studies.

Note: The above story is based on materials provided by United States Geological Survey.

Ascent or no ascent? How hot material is stopped in Earth’s mantle

April 24, 2015

A figure of the flood basalts that ascended through the Earth’s crust and reached the surface in Siberia Credit: GFZ

Gigantic volumes of hot material rising from the deep earth’s mantle to the base of the lithosphere have shaped the face of our planet. Provided they have a sufficient volume, they can lead to break-up of continents or cause mass extinction events in certain periods of the Earth’s history. So far it was assumed that because of their high temperatures those bodies – called mantle plumes – ascend directly from the bottom of the earth’s mantle to the lithosphere. In the most recent volume of Nature Communications, a team of researchers from the Geodynamic Modeling Section of German Research Centre for Geosciences GFZ explains possible barriers for the ascent of these mantle plumes and under which conditions the hot material can still reach the surface. In addition, the researchers resolve major conflicts surrounding present model predictions.

The largest magmatic events on Earth are caused by massive melting of ascending large volumes of hot material from the Earth’s interior. The surface manifestations of these events in Earth’s history are still visible in form of the basaltic rocks of Large Igneous Provinces. The prevailing concept of mantle plumes so far was that because of their high temperatures, they have strongly positive buoyancy that causes them to ascend and uplift the overlying Earth’s surface by more than one kilometer. In addition, it was assumed that these mantle plumes are mushroom-shaped with a large bulbous head and a much thinner tail with a radius of only 100 km, acting as an ascent channel for new material. But here is the problem: In many cases, this concept does not agree with geological and geophysical observations, which report much wider zones of ascending material and much smaller surface uplift.

The solution is to incorporate observations from plate tectonics: In many places on the Earth’s surface, such as in the subduction zones around the Pacific, ocean floor sinks down into the Earth’s mantle. Apparently, this material descends up to a great depth in the Earth’s mantle over several millions of years. This former ocean floor has a different chemical composition than the surrounding Earth’s mantle, leading to a higher density. If this material is entrained by mantle plumes, which is indicated by geochemical analyses of the rocks of Large Igneous Provinces, the buoyancy of the plume will decrease. However, this opens up the question if this hot material is still buoyant enough to rise all the way from the bottom of the Earth’s mantle to the surface.

GFZ-researcher Juliane Dannberg: “Our computer simulations show that on the one hand, the temperature difference between the plume and the surrounding mantle has to be high enough to trigger the ascent of the plume. On the other hand, a minimum volume is required to cross a region in the upper mantle where the prevailing pressures and temperatures lead to minerals with a much higher density than the surrounding rocks.”

Under these conditions, mantles plumes with very low buoyancy can develop, preventing them from causing massive volcanism and environmental catastrophes, but instead making them pond inside of the Earth’s mantle. However, mantle plumes that are able to ascend through the whole mantle are much wider, remain in the Earth’s mantle for hundreds of millions of years and only uplift the surface by a few hundred meters, which agrees with observations.

Reference:
Juliane Dannberg, Stephan V. Sobolev. Low-buoyancy thermochemical plumes resolve controversy of classical mantle plume concept. Nature Communications, 2015; 6: 6960 DOI: 10.1038/ncomms7960

Note: The above story is based on materials provided by Helmholtz Centre Potsdam – GFZ German Research Centre for Geosciences.

Geothermal energy, aluto volcano, and Ethiopia’s rift valley

April 24, 2015

Conceptual model summarizing the evolution of the major structures on Aluto volcano and their controls on surface volcanism, geothermal fluids, and degassing. Credit: Hutchison et al. and Geosphere

In their open access paper published in Geosphere this month, William Hutchison and colleagues present new data from Ethiopia’s Rift Valley and Aluto volcano, a major volcano in the region. Aluto is Ethiopia’s main source of geothermal energy, a low-carbon resource that is expected to grow considerably in the near future. Preexisting volcanic and tectonic structures have played a key role in the development of the Aluto volcanic complex and continue to facilitate the expulsion of gases and geothermal fluids.

Using high-resolution airborne imagery, field observations, and CO2 degassing data, the authors explore in great detail how these preexisting structures control fluid pathways and spatial patterns of volcanism, hydrothermal alteration, and degassing. Understanding these preexisting structures, they write, “Is a major task toward defining the evolution of rift zones and also has important implications for geothermal exploration, mineralization, and the assessment of volcanic hazard.”

In concluding their paper, Hutchison and colleagues write, “The new model for the structural development and volcanic edifice growth at Aluto opens up a number of avenues for future work. A major challenge is to determine how geothermal and magmatic fluids are distributed and stored in the subsurface of Aluto and how they ascend along the mapped fault zones.” These future studies, they note, “should focus on generating high-spatial-resolution maps of off-rift tectonic structures and should be complemented by detailed field work to constrain the stress field orientations during the development of the Aluto magma reservoir.”

Reference:
Structural controls on fluid pathways in an active rift system: A case study of the Aluto volcanic complex, William Hutchison et al., COMET, University of Oxford, Oxford, UK. Published online on 2 Apr. 2015; DOI: 10.1130/GES01119.1.

Note : The above story is based on materials provided by Geological Society of America.

New Insight on Ground Shaking from Man-Made Earthquakes

April 24, 2015

Research has identified 17 areas in the central and eastern United States with increased rates of induced seismicity. Since 2000, several of these areas have experienced high levels of seismicity, with substantial increases since 2009 that continue today. Credit: Image courtesy of USGS

Significant strides in science have been made to better understand potential ground shaking from induced earthquakes, which are earthquakes triggered by man-made practices.

Earthquake activity has sharply increased since 2009 in the central and eastern United States. The increase has been linked to industrial operations that dispose of wastewater by injecting it into deep wells.

The U. S. Geological Survey (USGS) released a report today that outlines a preliminary set of models to forecast how hazardous ground shaking could be in the areas where sharp increases in seismicity have been recorded. The models ultimately aim to calculate how often earthquakes are expected to occur in the next year and how hard the ground will likely shake as a result. This report looked at the central and eastern United States; future research will incorporate data from the western states as well.

This report also identifies issues that must be resolved to develop a final hazard model, which is scheduled for release at the end of the year after the preliminary models are further examined. These preliminary models should be considered experimental in nature and should not be used for decision-making.

USGS scientists identified 17 areas within eight states with increased rates of induced seismicity. Since 2000, several of these areas have experienced high levels of seismicity, with substantial increases since 2009 that continue today. This is the first comprehensive assessment of the hazard levels associated with induced earthquakes in these areas. A detailed list of these areas is provided in the accompanying map, including the states of Alabama, Arkansas, Colorado, Kansas, New Mexico, Ohio, Oklahoma, and Texas.

Scientists developed the models by analyzing earthquakes in these zones and considering their rates, locations, maximum magnitude, and ground motions.

“This new report describes for the first time how injection-induced earthquakes can be incorporated into U.S. seismic hazard maps,” said Mark Petersen, Chief of the USGS National Seismic Hazard Modeling Project. “These earthquakes are occurring at a higher rate than ever before and pose a much greater risk to people living nearby. The USGS is developing methods that overcome the challenges in assessing seismic hazards in these regions in order to support decisions that help keep communities safe from ground shaking.”

In 2014, the USGS released updated National Seismic Hazard Maps, which describe hazard levels for natural earthquakes. Those maps are used in building codes, insurance rates, emergency preparedness plans, and other applications. The maps forecast the likelihood of earthquake shaking within a 50-year period, which is the average lifetime of a building. However, these new induced seismicity products display intensity of potential ground shaking from induced earthquakes in a one-year period. This shorter timeframe is appropriate because the induced activity can vary rapidly with time and is subject to commercial and policy decisions that could change at any point.

These new methods and products result in part from a workshop hosted by the USGS and the Oklahoma Geological Survey. The workshop, described in the new report, brought together a broad group of experts from government, industry and academic communities to discuss the hazards from induced earthquakes.

Wastewater that is salty or polluted by chemicals needs to be disposed of in a manner that prevents contaminating freshwater sources. Large volumes of wastewater can result from a variety of processes, such as a byproduct from energy production. Wastewater injection increases the underground pore pressure, which may lubricate nearby faults thereby making earthquakes more likely to occur. Although the disposal process has the potential to trigger earthquakes, most wastewater disposal wells do not produce felt earthquakes.

Many questions have been raised about whether hydraulic fracturing—commonly referred to as “fracking”—is responsible for the recent increase of earthquakes. USGS’s studies suggest that the actual hydraulic fracturing process is only occasionally the direct cause of felt earthquakes.

Reference:
Read the newly published USGS report, “Incorporating Induced Seismicity in the 2014 United States National Seismic Hazard Model—Results of 2014 Workshop and Sensitivity Studies.”. DOI: 10.3133/ofr20151070

Note: The above story is based on materials provided by USGS.

Calbuco Volcano Eruption,Chile , April 23, 2015

April 24, 2015

The Calbuco volcano erupted Wednesday for the first time in over 40 years, billowing a huge ash cloud over a sparsely populated, mountainous area in southern Chile. Authorities ordered the evacuation of the 1,500 inhabitants of the nearby town of Ensenada, along with residents of two smaller communities.

How earthquake safety measures could have saved thousands of lives in Nepal

Vast vulnerability

Rebuilding a nation

Rare whale fossil found in Panama clarifies evolution of sperm whale

How cracking explains underwater volcanoes and the Hawaiian bend

Perspectives on the Nepal earthquake

Video

Landslides, mudslides likely to remain a significant threat in Nepal for months

Engineering a better future for the Mississippi Delta

DNA suggests all early eskimos migrated from Alaska’s North Slope

Ancient connection between the Americas enhanced extreme biodiversity

Researchers find evidence of groundwater in Antarctica’s Dry Valleys

Video

Road cracks after Nepal earthquake

Bizarre ‘platypus’ dinosaur discovered

Tidal tugs on Teflon faults drive slow-slipping earthquakes

Calbuco volcano – evacuations and air-traffic disruption follow eruption

Video

Chemistry of seabed’s hot vents could explain emergence of life

Platinum

Physical Properties of Platinum

Photos:

Map shows content and origins of the geologic basement

Ascent or no ascent? How hot material is stopped in Earth’s mantle

Geothermal energy, aluto volcano, and Ethiopia’s rift valley

New Insight on Ground Shaking from Man-Made Earthquakes

Calbuco Volcano Eruption,Chile , April 23, 2015

Related Articles

Extreme geothermal activity discovered beneath New Zealand’s Southern Alps

Tiny Australian wallaby the last living link to extinct giant kangaroos

Human skull evolved along with two-legged walking, study confirms

6.24 million year old species is size of modern wolf

China using animals to predict earthquakes

Perspectives on the Nepal earthquake