Huge bolts of pryoclastic lightning flash as the Calbuco volcano in southern Chile erupts Credit: Martin Bernetti/AFP
A new study shows that relatively small external disturbances play a crucial role in chaotic phenomena like the recent Calbuco volcanic eruption in Chile, leading to drum-beat-like seismicity.
Volcanoes are considered chaotic systems. They are difficult to model because the geophysical and chemical parameters in volcanic eruptions exhibit high levels of uncertainty. Now, Dmitri V. Alexandrov and colleagues from the Ural Federal University in Ekaterinburg, in the Russian Federation, have further extended an eruption model — previously developed by other scientists — to the friction force at work between the volcanic plug and volcanic conduit surface. The results, published in EPJB, provide evidence that volcanic activity can be induced by external noises that would not otherwise have been predicted by the model.
Predicting when, where and how volcanic eruptions will happen is likely to remain empirical. That is, until it is possible to improve the modelling of their dynamics. The challenge of such models is that the volcanic eruption dynamics are very complex, involving simultaneous unrelated processes and offering a variety of possible scenarios.
The authors built on a previous study demonstrating the influence of noise in triggering eruptions. Namely, they assumed that, under complex friction forces, the volcano plug and conduit exhibit a previously identified mechanism, called stick-slip behaviour, which causes the volcanic plug to rise and fall in an attenuated manner. They then studied the influence of random disturbances on these dynamics. They also tested the resulting model with experimental data from the Mount St. Helen’s eruption, dating back to 2004 and 2005.
Alexandrov and colleagues show that the external noise is also linked to the appearance of large-amplitude oscillations in the volcanic plug and high seismicity. An increase in noise intensity leads to drumbeat-type plug movement, exhibiting irregular periodicity dependent on noise. Such beat-type behaviour is a building block for understanding the physical mechanisms of volcanic drumbeat seismicity.
Reference:
Dmitri V. Alexandrov, Irina A. Bashkirtseva, Lev B. Ryashko. How a small noise generates large-amplitude oscillations of volcanic plug and provides high seismicity. The European Physical Journal B, 2015; 88 (4) DOI: 10.1140/epjb/e2015-60130-6
This graphic illustrates separating rare earth metals with UV light. Credit: KU Leuven – Department of Chemical Engineering
Researchers from the KU Leuven Department of Chemical Engineering have discovered a method to separate two rare earth elements — europium and yttrium — with UV light instead of with traditional solvents. Their findings, which were published in Green Chemistry, offer new opportunities for the recycling of fluorescent lamps and low-energy light bulbs.
Europium and yttrium are two rare earth metals that are commonly used in sustainable technology and high-tech applications. As these rare earth metals are difficult to mine, there is a great interest in recycling them. Europium and yttrium can be recovered from red lamp phosphor, a powder that is used in fluorescent lamps such as neon tubes.
In early 2015, KU Leuven chemists developed ionic liquid technology to recycle europium and yttrium from collected fluorescent lamps and low-energy light bulbs. Their method recycles the red lamp phosphor as a whole to reuse the powder in lamps. For other applications, however, it is necessary to separate europium and yttrium from the rare-earth mixture.
Separating the two rare earth elements is a complicated process. Professor Tom Van Gerven from the Department of Chemical Engineering explains: “The traditional method dissolves europium and yttrium in aqueous acid. An extractant and a solvent are then added to the aqueous liquid, leading to two separate layers known as ‘phases’: an aqueous layer containing the rare earth metals and a solvent layer with the extractant. When the two layers come into contact, one of the two rare earth metals is extracted to the solvent, while the other rare earth metal remains in the aqueous layer.”
But this process leaves much to be desired in terms of efficiency and purity: it needs to be repeated dozens of times to recover a high percentage of a particular rare earth metal, and there will still be traces of yttrium in the europium-containing liquid and vice versa.”
In collaboration with KU Leuven chemists the researchers have now managed to recover europium from the liquid mixture with UV light instead of a solvent. “The UV light influences the electrically charged particles known as ions. Both europium and yttrium have three positive charges per ion. When we shine UV light upon the solution of europium and yttrium, we add energy to the system. As a result, one positive charge per europium ion is neutralized. When we add sulphate, only the europium reacts with it. The result is a precipitate that can easily be filtered, while the yttrium remains in the solution,” says Bart Van den Bogaert, who is preparing a PhD on the subject.
The advantages of UV light are that it does not leave behind any harmful chemicals in the liquid and that the separation efficiency and purity in synthetic mixtures is very high: more than 95% of the europium is recovered from the solution. The precipitate itself is 98,5% pure, so it contains hardly any traces of yttrium. A similar purity was obtained with industrial mixtures, but the efficiency of the separation still needs to be improved. That will be one of the next projects tackled by the KU Leuven researchers.
Reference:
Bart Van den Bogaert, Daphné Havaux, Koen Binnemans, Tom Van Gerven. Photochemical recycling of europium from Eu/Y mixtures in red lamp phosphor waste streams. Green Chem., 2015; 17 (4): 2180 DOI: 10.1039/C4GC02140A
An international group of scientists has proposed that fallout from hundreds of nuclear weapons tests in the late 1940s to early 1960s could be used to mark the dawn of a new geological age in Earth history — the Anthropocene.
The study, led by Dr Colin Waters of the British Geological Survey, published new research in the Bulletin of the Atomic Scientists. The research involved 10 members of the Anthropocene Working Group that is chaired by Professor Jan Zalasiewicz of the Department of Geology at the University of Leicester and Gary Hancock, a world expert on plutonium in the environment.
The researchers state that the mid-twentieth century coincides with the ‘Great Acceleration’ of human population growth, economic development and industrialization. The emergence of megacities, facilitated by the production of huge quantities of concrete, is coincident with earth movement on a vast scale. Mineral exploitation has resulted in the generation of marked geochemical signatures across the globe and this age of hydrocarbon burning has resulted in greatly increased carbon emissions. Humanity’s modification of the planet has caused an increase in species extinctions and invasions. All these features are being expressed in the sediments accumulating across the planet and will be recognizable to the geoscientists of the far future.
They pose the question: “If the sum of these changes is a recognition that we now live in a new epoch, the Anthropocene, how can we define when it started?”
The standard practice for defining geological time units is to identify a single reference point (or “golden spike”) that fixes the lower boundary of the time unit within a succession of rock or sediment layers. The boundary should be characterized by a signature that is both rapidly developed and wide-spread. The proposal led by Dr Waters is that the programme of atmospheric nuclear weapons testing may have generated such a signature.
Dr Waters said: “It is sobering to think that the actions of humanity over a few short years in the mid-20th century created such large amounts of artificial radionuclides that scattered across the Earth as fallout, producing a signal in modern strata that, in the case of plutonium, will be a detectable for about 100,000 years into the future.”
Starting with the 1945 detonation of the Trinity device in New Mexico, the extent of such fallout was initially quite localized. But with the introduction in 1952 of the much larger “thermonuclear” or “hydrogen” weapons tests, the fallout dispersed over the entire Earth surface. The amount of fallout peaked in 1962, the year before the Partial Nuclear Test-Ban Treaty largely drove the nuclear detonations underground. The 1952 rise in abundance of the isotope plutonium-239 is preferred as it is rare in nature, is a significant component of fallout, is relatively immobile in sediments, has a long half-life so will persist long into the future and the rise is broadly coincident with the onset of the “Great Acceleration.”
Professor Zalasiewicz said: “The Anthropocene has struck a chord in the wider world that none of the other geological time units have done — not even the dinosaur-haunted Jurassic. Human beings don’t merely inhabit the world. They alter it, on an increasingly epic scale.”
In 2016, the Anthropocene Working Group hopes to make recommendations on whether this new time unit should be formalized and, if so, how it might be defined and characterized.
Reference:
C. N. Waters, J. P. M. Syvitski, A. Gauszka, G. J. Hancock, J. Zalasiewicz, A. Cearreta, J. Grinevald, C. Jeandel, J. R. McNeill, C. Summerhayes, A. Barnosky. Can nuclear weapons fallout mark the beginning of the Anthropocene Epoch? Bulletin of the Atomic Scientists, 2015; 71 (3): 46 DOI: 10.1177/0096340215581357
Calcit crystals in the Alum Shale as indicators of methane formation Credit: GFZ
Considering geological time scales, the occurrence of biogenic shale gas in Sweden´s crust is relatively young. An international team of geoscientists (led by Hans-Martin Schulz, German Research Centre for Geosciences GFZ) found that biogenic methane in the Alum Shale in South Sweden formed due to deglaciation around 12.000 years ago. Moreover, the formation processes were due to complex interactions between neotectonic activity and the occurrence of a deep biosphere. Applying a new hydrogeochemical modelling approach, the specific methane generation process was unravelled and quantified for the first time in Europe.
Around 300 million years ago the Variscan Mountain belt was formed in Central Europe. Its orogeny and uplift was coupled to extensional movements in today´s Northern Europe. As a result, mafic magmas intruded the early Palaeozoic rock sequence and led to oil formation in the Alum Shale followed by its expulsion. Migrating bitumens impregnated the Alum Shale outside the area of thermal influence.
The melting of the up to three kilometers thick glaciers at the end of the last glaciation led to a beginning uplift of the formerly glaciated Baltic Sea region which still today rises by up to 10 mm per year. A consequence of this uplift tendency is the formation of fractures along which melting water migrated into the subsurface. It is important to note that low contents of dissolved solids in formation water is a prerequisite for methanogenic microbes to convert soluble oil components into methane. Accordingly, methane is stored in black shale today and can be found up to approximately 100 meters depth.
Up to now, similar biogenic methane resources were exclusively known from North America which was glaciated as Northern Europe. The most prominent example is the Antrim Shale of Devonian age in Michigan.
Reference:
Hans-Martin Schulz, Steffen Biermann, Wolfgang van Berk, Martin Krüger, Nontje Straaten, Achim Bechtel, Richard Wirth, Volker Lüders, Niels Hemmingsen Schovsbo, and Stephen Crabtree. From shale oil to biogenic shale gas: Retracing organic–inorganic interactions in the Alum Shale (Furongian–Lower Ordovician) in southern Sweden. AAPG Bulletin, May 2015 DOI: 10.1306/10221414014
A wild-type Chironomus larva with normal head (left) and abdomen (right) development is shown. Credit: Urs Schmidt-Ott/University of Chicago
Newly evolved genes can rapidly assume control over fundamental functions during early embryonic development, report scientists from the University of Chicago. They identified a gene, found only in one specific group of midge flies, which determines the patterning of the head and tail in developing embryos. This newly discovered gene has the same developmental role as an unrelated, previously-known gene which appears to have been lost or altered in certain fly families during evolution. The findings, published in Science on May 7, suggest that evolutionary changes to the genetics of fundamental biological processes occur more frequently than previously thought.
“The genes that drive embryonic polarity are not conserved across flies and their evolutionary replacement does not seem to be rare at all,” said study senior author Urs Schmidt-Ott, PhD, associate professor of organismal biology and anatomy at the University of Chicago. “The hijacking of this early developmental pathway by novel or newly evolved genes happens at a much higher frequency than previously thought.”
In the common fruit fly Drosophila and related flies, the gene bicoid determines which end of an embryo will develop into the head and which will become the tail. However, most flies and other insects lack bicoid, and how they establish this head-to-tail polarity has been poorly understood. Early studies of chironomids, a group of mosquito-like midges, found that ultraviolet light or RNAse targeted toward the front portion of embryos led to double-abdomen formation (two tail ends and no head), which suggested that localized RNA in the anterior egg might function as head determinant.
To identify which gene products were being disrupted, Schmidt-Ott’s team profiled and compared gene expression levels between the front and rear halves of Chironomus embryos. Out of thousands of candidates, the team identified a specific gene, which appeared to be necessary for the formation of head-to-tail polarity. Double-abdomen formation occurred when this gene, called panish, was silenced in early Chironomus embryos. These embryos could be returned to normal with the addition of an independent source of panish gene product.
Although panish and bicoid perform essentially the same function, they are structurally unrelated and found in completely separate families of flies. Both genes act by regulating other genes involved in genetic patterning, but panish represses them while bicoid activates them.
The team found no evidence of panish in flies other than Chironomus, suggesting that panish is a newly evolved gene that appropriated the function of regulating head-to-tail polarity. They also reexamined the occurrence of bicoid and discovered that the gene has been repeatedly lost or substantially altered in certain fruit flies and tsetse flies during evolution.
Despite the importance of head-to-tail patterning in early embryonic development, it appears that genes that regulate the process are poorly conserved in flies, and that new genes took over the role far more often than previously thought.
The discovery of this phenomenon now opens a multitude of new research avenues. Schmidt-Ott and his colleagues are now investigating questions such as how do genes appropriate new roles, why it happens so frequently and whether such instances share common features.
“It’s astonishing how a newly evolved gene can, in a very short amount of time, take over control of such a fundamental process,” Schmidt-Ott said. “Given that a small sample of examined genomes already suggests four independent fundamental substitutions, we probably are looking at the ‘tip of the iceberg’ for these events.”
Reference:
Jeff Klomp, Derek Athy, Chun Wai Kwan, Natasha I. Bloch, Thomas Sandmann, Steffen Lemke, Urs Schmidt-Ott. A cysteine-clamp gene drives embryo polarity in the midge Chironomus. DOI: 10.1126/science.aaa7105
Mimulus peregrinus — the foreigner, is a new flower species native to Scotland. Credit: University of Stirling
A Stirling scientist who discovered a new Scottish flower has made an unexpected second finding which provides unique insight into our understanding of evolution.
Dr Mario Vallejo-Marin, a Plant Evolutionary Biologist at the University of Stirling, first unearthed a new species of monkeyflower on the bank of a stream in South Lanarkshire, Southern Scotland in 2012.
A subsequent expedition two years later led Dr Vallejo-Marin to locate the impressive yellow flower some 350 miles north, near Stromness on the Orkney Islands off the north coast of Scotland.
“Orkney was a missing region which hadn’t been sampled,” explained Dr Vallejo-Marin, Senior Lecturer in the School of Natural Sciences. “There were different varieties of monkey flower on the island, but when we spotted this population I knew it was unusual as after looking at hundreds of plants, you get to recognise the subtle differences.
“Usually a species forms once in a particular location then spreads to other regions. In this case, the opposite has occurred as the same species has evolved multiple times in different places. It shows that when the conditions are right, the origin of species is a repeatable phenomenon.”
After the initial discovery, Dr Vallejo-Marin named the species Mimulus peregrinus – which translates as ‘the foreigner’ – given its origins from two invasive species first brought to the UK from the USA and South America in the 1800s.
It was a particularly rare find given hybrid plants of its kind are normally infertile. Instead, it doubled the amount of DNA in its cells and evolved to form a new species in a process known as polyploidisation, the same mechanism by which Wheat, Cotton and Tobacco originated.
Dr Vallejo-Marin added: “It is impossible to say whether Mimulus peregrinus evolved first in the south or in the north of Scotland, but our discovery of a very young species of this kind has allowed us to study evolution as it happens. We only know of a handful of other plant species as young as Mimulus peregrinus and so in this respect it is like looking at the big bang in the first milliseconds of its occurrence.
“The process of evolution it has followed is particularly interesting and adds complexity to our conception of the tree of life. Instead of branching out as it grows, Mimulus peregrinus is an example of how some branches can come back together again and spawn new species that are in part the combination of their ancestors.”
Dr Vallejo-Marin’s research is published in the Journal Evolution. The research was completed with UK colleagues from Queen Mary University of London and with Whitman College and the College of William and Mary in the USA.
Reference:
Mario Vallejo-Marín, Richard J. A. Buggs, Arielle M. Cooley andJoshua R. Puzey. Speciation by genome duplication: Repeated origins and genomic composition of the recently formed allopolyploid species Mimulus peregrinus. DOI: 10.1111/evo.12678
This is the Agham fluvial terrace, located roughly 400 m above the current river level of the upper Shyok valley, NW Himalayas, India. See related article by J.H. Blöthe and colleagues. Credit: J.H. Blöthe and colleagues and Geology
Large landslides are an important process of erosion in the Himalaya-Karakoram ranges (HKR). These high-relief landscapes are characterized by steep slopes that are prone to frequent landsliding. By mapping nearly 500 large (greater than 0.1 km2) landslides in the HKR, Jan Henrik Blöthe and colleagues find that the vast majority of these mass movements lie in the lower portions of the landscape, whereas glaciers and rock glaciers occupy the higher elevations almost exclusively.
These findings suggest that different processes dominate the gross erosion in the HKR at different elevations: Large landslides appear to preferentially undermine the topography in response to incision along major rivers, whereas glacial erosion and/or more frequent and smaller slope failures, associated with intense frost action, compensate for this role at higher elevations.
In this study published in Geology, Blöthe and colleagues introduce a new method that they term excess topography (ZE) to identify the location of potentially unstable rock-mass volumes. They find that locations with high values of ZE are concentrated near or below the median elevation, which is also where the majority of the mapped landslides occur, and conclude that the HKR are characterized by two vertical domains of landslide and (peri-)glacial erosion that may respond to different time scales of perturbation
Reference:
Large landslides lie low: Excess topography in the Himalaya-Karakoram ranges
Jan Henrik Blöthe et al., University of Potsdam, Potsdam, Germany; and University of Bonn, Bonn, Germany. Published online ahead of print on 27 Apr. 2015; DOI: 10.1130/G36527.1.
Odaraia alata, an arthropod resembling a submarine from the middle Cambrian Burgess Shale. Credit: Jean Bernard Caron (Royal Ontario Museum)
A new study from the University of Cambridge has identified one of the oldest fossil brains ever discovered – more than 500 million years old – and used it to help determine how heads first evolved in early animals. The results, published today (7 May) in the journal Current Biology, identify a key point in the evolutionary transition from soft to hard bodies in early ancestors of arthropods, the group that contains modern insects, crustaceans and spiders.
The study looked at two types of arthropod ancestors – a soft-bodied trilobite and a bizarre creature resembling a submarine. It found that a hard plate, called the anterior sclerite, and eye-like features at the front of their bodies were connected through nerve traces originating from the front part of the brain, which corresponds with how vision is controlled in modern arthropods.
The new results also allowed new comparisons with anomalocaridids, a group of large swimming predators of the period, and found key similarities between the anterior sclerite and a plate on the top of the anomalocaridid head, suggesting that they had a common origin. Although it is widely agreed that anomalocaridids are early arthropod ancestors, their bodies are actually quite different. Thanks to the preserved brains in these fossils, it is now possible to recognise the anterior sclerite as a bridge between the head of anomalocaridids and that of more familiar jointed arthropods.
“The anterior sclerite has been lost in modern arthropods, as it most likely fused with other parts of the head during the evolutionary history of the group,” said Dr Javier Ortega-Hernández, a postdoctoral researcher from Cambridge’s Department of Earth Sciences, who authored the study. “What we’re seeing in these fossils is one of the major transitional steps between soft-bodied worm-like creatures and arthropods with hard exoskeletons and jointed limbs – this is a period of crucial transformation.”
Ortega-Hernández observed that bright spots at the front of the bodies, which are in fact simple photoreceptors, are embedded into the anterior sclerite. The photoreceptors are connected to the front part of the fossilised brain, very much like the arrangement in modern arthropods. In all likelihood these ancient brains processed information like in today’s arthropods, and were crucial for interacting with the environment, detecting food, and escaping from predators.
During the Cambrian Explosion, a period of rapid evolutionary innovation about 500 million years ago when most major animal groups emerge in the fossil record, arthropods with hard exoskeletons and jointed limbs first started to appear. Prior to this period, most animal life on Earth consisted of enigmatic soft-bodied creatures that resembled algae or jellyfish.
These fossils, from the collections of the Royal Ontario Museum in Toronto and the Smithsonian Institution in Washington DC, originated from the Burgess Shale in Western Canada, one of the world’s richest source of fossils from the period.
Since brains and other soft tissues are essentially made of fatty-like substances, finding them as fossils is extremely rare, which makes understanding their evolutionary history difficult. Even in the Burgess Shale, one of the rare places on Earth where conditions are just right to enable exceptionally good preservation of Cambrian fossils, finding fossilised brain tissue is very uncommon. In fact, this is the most complete brain found in a fossil from the Burgess Shale, as earlier results have been less conclusive.
“Heads have become more complex over time,” said Ortega-Hernández, who is a Fellow of Emmanuel College. “But what we’re seeing here is an answer to the question of how arthropods changed their bodies from soft to hard. It gives us an improved understanding of the origins and complex evolutionary history of this highly successful group.”
UC Berkeley seismologists were surprised last August to see a dramatic increase in faint tremors occurring under the San Andreas Fault near Parkfield, in Central California, about 10 hours after a magnitude 6.0 earthquake struck Napa. Somehow, that quake triggered tiny rumblings 250 miles away that lasted for about 100 days before dropping off.
These same researchers have recently found two other places in California where tremors are happening below the zone where earthquakes normally occur, and have now embarked on a comprehensive search for tremors throughout the state.
Key to discovering the connection between tremors and earthquakes is TremorScope, a set of four seismic stations to be placed about 900 feet underground near Parkfield to listen for these faint whispers. They will be added to four new surface stations already deployed as a part of the project.
“It’s a big job, but we hope to develop a near-real-time tremor monitoring capability in the TremorScope area and elsewhere,” said UC Berkeley seismologist Robert Nadeau, who will be working on the project with help from the Berkeley Institute for Data Science.
TremorScope is funded by a $1.2 million grant from the Gordon and Betty Moore Foundation.
“Tremors are associated with big, very slow movements on the fault, and there is speculation that they might cause big earthquakes,” said research seismologist Peggy Hellweg, UC Berkeley project lead for TremorScope and operations manager at the Berkeley Seismological Laboratory. “But we see tremor activity with earthquakes and earthquakes without tremor, so the connection is still unclear.”
Tremors originate beneath the zone where earthquakes occur and appear to be associated with slipping rocks deep in the earth. UC Berkeley seismologists discovered tremors just south of the Parkfield area of the San Andreas Fault in 2004, and subsequent studies suggest that changes in tremor activity may precede earthquakes. Tremors also have been detected in active earthquake zones in Japan, Washington state and other subduction zones around the world.
TremorScope is designed to measure these tremors more precisely than ever before, using geophones sensitive to high-frequency ground movement and broadband seismometers able to record low-frequency rumblings. Geophones and broadband seismometers are to be installed in four deep boreholes drilled around an area of the San Andreas Fault near Parkfield that seems to be the center of tremor activity where the northern and southern segments of the fault meet. The borehole instruments, which can detect quieter tremors because of less noise underground, complement instruments already in place at four surface stations in the area.
A surface accelerometer was installed in January at a site on the property of Cass Vineyard and Winery, located 12 miles east of Highway 101 near Paso Robles. The borehole instruments will be installed at the winery site May 6 and 7, with installation of the three other borehole seismometers scheduled in the coming months.
“With the four surface seismometers now installed, TremorScope is already helping us to locate tremor,” Nadeau said. “The deeper borehole seismometers will be able to give us a range of frequencies at higher resolution to figure out what is going on underground.”
Video
Seismologist Peggy Hellweg explains the TremorScope project, which involves four subsurface borehole seismometers and four surface seismometers to monitor faint tremors under the San Andreas Fault near Parkfield. Video by Roxanne Makasdjian and Phil Ebiner.
Geophysicist Horst Rademacher explains how a simple seismograph records the Earth’s shaking. Video by Roxanne Makasdjian and Phil Ebiner.
Artist’s impression of a rocky and water-rich asteroid being torn apart by the strong gravity of the white dwarf star. Similar objects in the Solar System likely delivered the bulk of water on Earth and represent the building blocks of the terrestrial planets. Credit: Image copyright Mark A. Garlick, space-art.co.uk, University of Warwick
Water delivery via asteroids or comets is likely taking place in many other planetary systems, just as it happened on Earth, new research strongly suggests.
Published by the Royal Astronomical Society and led by the University of Warwick, the research finds evidence for numerous planetary bodies, including asteroids and comets, containing large amounts of water.
The research findings add further support to the possibility water can be delivered to Earth-like planets via such bodies to create a suitable environment for the formation of life.
Commenting on the findings lead researcher Dr Roberto Raddi, of the University of Warwick’s Astronomy and Astrophysics Group, said: “Our research has found that, rather than being unique, water-rich asteroids similar to those found in our Solar System appear to be frequent. Accordingly, many planets may have contained a volume of water, comparable to that contained in the Earth.
“It is believed that the Earth was initially dry, but our research strongly supports the view that the oceans we have today were created as a result of impacts by water-rich comets or asteroids.”
In observations obtained at the William Herschel Telescope in the Canary Islands, the University of Warwick astronomers detected a large quantity of hydrogen and oxygen in the atmosphere of a white dwarf (known as SDSS J1242+5226). The quantities found provide the evidence that a water-rich exo-asteroid was disrupted and eventually delivered the water it contained onto the star.
The asteroid, the researchers discovered, was comparable in size to Ceres — at 900km across, the largest asteroid in the Solar System.
“The amount of water found SDSS J1242+5226 is equivalent to 30-35% of the oceans on Earth,” explained Dr Raddi.
The impact of water-rich asteroids or comets onto a planet or white dwarf results in the mixing of hydrogen and oxygen into the atmosphere. Both elements were detected in large amounts in SDSS J1242+5226.
Research co-author Professor Boris Gänsicke, also of University of Warwick, explained: “Oxygen, which is a relatively heavy element, will sink deep down over time, and hence a while after the disruption event is over, it will no longer be visible.
“In contrast, hydrogen is the lightest element; it will always remain floating near the surface of the white dwarf where it can easily be detected. There are many white dwarfs that hold large amounts of hydrogen in their atmospheres, and this new study suggests that this is evidence that water-rich asteroids or comets are common around other stars than the Sun.”
Reference:
R. Raddi, B. T. Gänsicke, D. Koester, J. Farihi, J. J. Hermes, S. Scaringi, E. Breedt and J. Girven. Likely detection of water-rich asteroid debris in a metal-polluted white dwarf,. Monthly Notices of the Royal Astronomical Society, 2015 (in press) DOI: 10.1093/mnras/stv701
UCLA’s William Newman, trained as an applied mathematician and theoretical physicist, has spent much of his career developing equations that explore the likelihood of earthquakes in certain regions. Credit: William Newman
In 2012, six Italian seismologists were sent to prison because they failed to predict the 2009 L’Aquila 6.3 magnitude earthquake.
To some that may seem absurd but it points to the faith so many have come to place in science’s ability to predict and prevent tragedies. Experts had for decades predicted that Nepal would experience a massive earthquake, but were unable to provide a more precise warning about the recent 7.8-magnitude quake that devastated the country. The Italian seismologists had similarly predicted earthquake probabilities but could not give an exact date.
Science and mathematics have not reached a point where they can forecast with certainty the exact time and specific severity of these cataclysmic events—and may never do so.
“The best we can do is make an assessment of there being a heightened risk in a certain geographic area over a certain window of time,” said William Newman, a theoretical physicist at the University of California, Los Angeles, who has received funding from the National Sceince Foundation (NSF) for his work aimed at improving natural hazard predictions. “We can determine a sense of what is likely to occur, but we will never know exactly.”
Newman has spent much of his 35-year career working in computational and applied mathematics but also has employed mathematics in applications to probe natural disaster issues such as earthquakes and climate change.
These days, mathematicians seem to be able to model almost anything, but, as Newman points out, the devil is not only in the details but in creating models that can be used for accurate prediction. In the case of tectonic plates, the randomness of their interaction limits the certainty of predictions, and those predictions become less certain as time passes. In much the same way that a weather forecaster can be more certain about predicting tomorrow’s weather than next month’s, Newman believes earthquake prediction accuracy has the potential to fall off.
“For mathematicians, three aspects come to mind,” Newman said. “We like to think of the equations being well posed, well defined, and that we can run with them. In [Edward] Lorenz’s case (whose model of turbulence celebrated its 50th anniversary recently), his equations about atmospheric behavior were, by and large, eminently reasonable. He supersimplified and saw that if he perturbed the initial conditions, after a certain amount of time, he could predict nothing.”
Yes, you read that right: nothing.
The problem for mathematicians is that forecasting accuracy can only weaken as more variables cloud the equations and models they build. In the case of earthquakes, Newman says the prospects for good predictions are even more dismal than for atmospheric ones. Chaotic dynamics and complexity prevail.
In Los Angeles, where Newman lives, mathematicians and geophysicists have worked together and determined that sometime in the next 30 years, the area is likely to see a substantial earthquake due to its proximity to the San Andreas Fault. And as each year passes, the risk increases in this window of time. The mathematicians can only put so many pre-determined variables into their equations, including the patterns of tectonic plate changes and the environmental conditions that coincide with earthquake occurrences.
“We have to go into this realizing there are bounds,” Newman said. “We are looking at complex systems that can produce patterns we just don’t understand.”
Additionally, while the news focuses on an earthquake and its aftershocks, there are also “foreshocks.” But recognizing a a foreshock is impossible without seeing the seismic event that follows. So trying to formulate day-to-day seismologic predictions after any earthquake event can also be confounding.
Why even try to predict earthquakes?
One could easily draw the conclusion at this point that we walk away from the issue, shaking our heads. But mathematicians, computer scientists, physicists, geologists, engineers, and social scientists working together on this issue do provide value, each adding something that could improve the scientific community’s understanding of this obviously complex issue.
As instruments become increasingly refined and data proliferate around the world, scientists also gain a better understanding of the consequences of earthquakes.
“It is true that scientists know very little about earthquake predictions,” said Junping Wang, program director in NSF’s mathematics division. “But this is exactly why we need to support earthquake research. Researching is the only way we can ever hope to build models that help to improve earthquake prediction and build a resilient society.”
As they conduct more research in seismology, scientists are able to gain more and better knowledge that can benefit local policymakers looking to enhance preparedness and emergency response to earthquakes and cascading disasters.
“There are still plenty of opportunities where scientific and mathematical research can improve our knowledge,” Wang said. “Understanding why an earthquake happened and how it happened helps us build better models, even if they can’t tell us a specific date and time. With increased knowledge comes better preparedness.”
Earthquake advice from a mathematician
“We can only tell people that there is a certain risk in a certain window of time,” Newman said. “Then it’s a matter of preparedness.”
He cites the example of the Northridge earthquake that rocked the UCLA Mathematical Sciences Building in 1994. Architects designed expansion joints in different sections of the building because they knew that, at some point, it would have to cope with the trauma of earthquakes. In that case, some of the offices went through an “unexpected expansion,” but Newman notes that ultimately the repairs were “essentially cosmetic.”
Newman, who carries the distinction of being a member of UCLA’s mathematics, physics and geology departments, routinely takes students to the San Andreas Fault—and specifically Vazquez Rocks, a set of formations exposed by seismic activity—for their research. He emphasizes that to prevent the fallout of earthquakes like the recent one in Nepal, policymaking that establishes building codes and individual preparedness are essential.
“If you live here, you have to earthquake-proof your home and your business. You need to be able to take care of yourself,” he said. “And then when an earthquake does occur, hopefully, it will just be an inconvenience.”
Here the Loki Archaeota were discovered: on the seabed at the Mid-Atlantic Ridge near the hydrothermal vents Loki’s Castle. Credit: Centre for Geobiology, Bergen, Norway, by R.B. Pedersen
New complex microorganisms discovered as closest relatives of complex organisms
Archaea belong together with Bacteria to the first organisms that emerged on Earth. These microorganisms existed hundreds of millions of years before the more complex cell structures of Eukaryotes developed that gave rise to macroscopic life, i.e. plants and animals. An international team of researchers from Uppsala (Sweden), Bergen (Norway) and Vienna (Austria), has found a novel group of Archaea in deep ocean sediments, who are the closest direct relatives of the eukaryotic lineage. Their genome shows an unexpected similarity to those of Eukaryotes. The results of this study appear in the current issue of the journal “Nature”.
How did the first complex eukaryotic cells with their organelles develop from simple prokaryotes, i.e. bacteria or archaea? This is a highly debated topic in evolutionary research but the question remains largely unresolved. Genomic research has shown that the organelles delivering energy in eukaryotic cells stem from an early bacterial symbiont. Since Archaea have also played an important role in the evolution of eukaryotes, current models suggested, that a primordial Archaeon might have engulfed a bacterium and in this event transformed into a complex eukaryotic cell. “With the discovery of Lokiarchaeota a missing link in this scenario has been found”, says Christa Schleper from the University of Vienna.
Surprises from the genome
In phylogenetic trees Lokiarchaeota (named after the Norwegian god Loki) form a direct sister group to Eukaryotes. This means that the ancestors of Eukaryotes emerged indeed directly from Archaea and do not form a separate domain in the tree of life. In addition, the genome of Lokiarchaeota reveals an unexpected complexity: It contains the genetic information for some proteins that were earlier only known from eukaryotes. Some of these proteins are responsible for membrane remodeling and for the formation of a cytoskeleton that determines the shape of a eukaryotic cell. “Exactly those features were needed by the primordial cell or primordial Archaeon to engulf a bacterium in the early stages of eukaryotic evolution”, says Anja Spang, one of the first authors of this study, who recently completed her PhD at the University of Vienna and now analysed the Loki genome in the group of Thijs Ettema in Uppsala.
The last common ancestor
“It is as if we had just discovered the primates i.e. the next living relatives of humans, who also give us interesting insights into the nature of the last common ancestor. However, the common ancestor of Lokiarchaeota and Eukaryotes dates much further back, approximately two billion years”, says Christa Schleper, “We are curious to analyse the life style and cellular structure of Lokiarchaeota, as it might give even more exciting insights into early evolution.”
Reference:
Anja Spang, Jimmy H. Saw, Steffen L. Jørgensen, Katarzyna Zaremba-Niedzwiedzka, Joran Martijn, Anders E. Lind, Roel van Eijk ,Christa Schleper, Lionel Guy and Thijs J.G. Ettema: Complex archaea that bridge the gap between prokaryotes and eukaryotes. In: Nature 2015 DOI: 10.1038/nature14447
A diagram illustrating the possible interior of Saturn’s moon Enceladus, including the ocean and plumes in the south polar region, was based on Cassini spacecraft observations, courtesy of NASA/JPL-Caltech. Credit: NASA/JPL-Caltech
New work from a team including Carnegie’s Christopher Glein has revealed the pH of water spewing from a geyser-like plume on Saturn’s moon Enceladus. Their findings are an important step toward determining whether life could exist, or could have previously existed, on the sixth planet’s sixth-largest moon.
Enceladus is geologically active and thought to have a liquid water ocean beneath its icy surface. The hidden ocean is the presumed source of the plume of water vapor and ice that the Cassini spacecraft has observed venting from the moon’s south polar region. Whenever there’s the possibility of liquid water on another planetary body, scientists begin to ask whether or not it could support life.
The present team, including lead author Glein, John Baross of the University of Washington, and J. Hunter Waite Jr. of the Southwest Research Institute, developed a new chemical model based on mass spectrometry data of ice grains and gases in Enceladus’ plume gathered by Cassini, in order to determine the pH of Enceladus’ ocean. The pH tells us how acidic or basic the water is. It is a fundamental parameter to understanding geochemical processes occurring inside the moon that are considered important in determining Enceladus’ potential for acquiring and hosting life. Their work is published in the journal Geochimica et Cosmochimica Acta.
The team’s model, constrained by observational data from two Cassini teams, including one led by coauthor Waite, shows that the plume, and by inference the ocean, is salty with an alkaline pH of about 11 or 12, which is similar to that of glass-cleaning solutions of ammonia. It contains the same sodium chloride (NaCl) salt as our oceans here on Earth. Its additional substantial sodium carbonate (Na2CO3) makes the ocean more similar to our planet’s soda lakes such as Mono Lake in California or Lake Magadi in Kenya. The scientists refer to it as a “soda ocean.”
“Knowledge of the pH improves our understanding of geochemical processes in Enceladus’ ‘soda ocean,'” Glein explained.
The model suggests that the ocean’s high pH is caused by a metamorphic, underwater geochemical process called serpentinization. On Earth, serpentinization occurs when certain kinds of so-called “ultrabasic” or “ultramafic” rocks (low in silica and high in magnesium and iron) are brought up to the ocean floor from the upper mantle and chemically interact with the surrounding water molecules. Through this process, the ultrabasic rocks are converted into new minerals, including the mineral serpentine, after which the process is named, and the fluid becomes alkaline. On Enceladus, serpentinization would occur when ocean water circulates through a rocky core at the bottom of its ocean.
“Why is serpentinization of such great interest? Because the reaction between the metallic rocks and the ocean water also produces molecular hydrogen (H2), which provides a source of chemical energy that is essential for supporting a deep biosphere in the absence of sunlight inside moons and planets,” Glein said. “This process is central to the emerging science of astrobiology, because molecular hydrogen can both drive the formation of organic compounds like amino acids that may lead to the origin of life, and serve as food for microbial life such as methane-producing organisms. As such, serpentinization provides a link between geological processes and biological processes. The discovery of serpentinization makes Enceladus an even more promising candidate for a separate genesis of life.”
Even beyond the search for life-hosting conditions on other planetary bodies, the team’s work demonstrates that it is possible to determine the pH of an extraterrestrial ocean based on chemical data from a spacecraft flying through a plume. This may be a useful approach to searching for habitable conditions in other icy worlds, such as Jupiter’s moon Europa.
“Our results show that this kind of synergy between observations and modeling can tell us a great deal about the geochemical processes occurring on a faraway celestial object, thus opening the door to an exciting new era of chemical oceanography in the solar system and beyond.” Glein added.
Cinder cone near Mount Lassen Photo Credit: Marli Miller
University of Oregon geologists have tapped water in surface rocks to show how magma forms deep underground and produces explosive volcanoes in the Cascade Range.
“Water is a key player,” says Paul J. Wallace, a professor in the UO’s Department of Geological Sciences and coauthor of a paper in the May issue of Nature Geoscience. “It’s important not just for understanding how you make magma and volcanoes, but also because the big volcanoes that we have in the Cascades — like Mount Lassen and Mount St. Helens — tend to erupt explosively, in part because they have lots of water.”
A five-member team, led by UO doctoral student Kristina J. Walowski, methodically examined water and other elements contained in olivine-rich basalt samples that were gathered from cinder cone volcanoes that surround Lassen Peak in Northern California, at the southern edge of the Cascade chain.
The discovery helps solve a puzzle about plate tectonics and Earth’s deep water cycle beneath the Pacific Ring of Fire, which scientists began studying in the 1960s to understand the region’s propensity for big earthquakes and explosive volcanoes. The ring stretches from New Zealand, along the eastern edge of Asia, north across the Aleutian Islands of Alaska and south along the coast of North and South America. It contains more than 75 percent of the planet’s volcanoes.
To understand how water affects subduction of the oceanic plate, in which layers of different rock types sink into the mantle, the UO team studied hydrogen isotopes in water contained in tiny blobs of glass trapped in olivine crystals in basalt.
To do so, the team used equipment in Wallace’s lab, CAMCOR, the Carnegie Institution in Washington, D.C., and a lab at Oregon State University. CAMCOR is UO’s Advanced Materials Characterization in Oregon, a high-tech extension service located in the underground Lorry I. Lokey Laboratories.
Next, the team fed data gained from the rocks into a complex computer model developed by co-author Ikudo Wada, then of Japan’s Tohoku University. She has since joined the University of Minnesota.
That combination opened a window on how rising temperatures during subduction drive water out of different parts of the subducted oceanic crust, Walowski said. Water migrates upwards and causes the top of the subducted oceanic crust to melt, producing magma beneath the Cascade volcanoes.
The key part of the study, Wallace said, involved hydrogen isotopes. “Most of the hydrogen in water contains a single proton,” he said. “But there’s also a heavy isotope, deuterium, which has a neutron in addition to the proton. It is important to measure the ratio of the two isotopes. We use this ratio as a thermometer, or probe, to study what’s happening deep inside the earth.”
“Melting of the subducting oceanic crust and the mantle rock above it would not be possible without the addition of water,” Walowski said. “Once the melts reach the surface, the water can directly affect the explosiveness of magma. However, evidence for this information is lost to the atmosphere during violent eruptions.”
Reference:
K. J. Walowski, P. J. Wallace, E. H. Hauri, I. Wada, M. A. Clynne. Slab melting beneath the Cascade Arc driven by dehydration of altered oceanic peridotite. Nature Geoscience, 2015; 8 (5): 404 DOI: 10.1038/ngeo2417
Casualty figures were highest for any recorded earthquake in the history of Nepal. In total 8519 people lost their lives in Nepal, A total of 126355 houses were severely damaged and around 80893 buildings were completely destroyed. Total money spent from the earthquake relief fund was NRs 206500 inside Kathmandu valley only. Earthquake relief fund was established by the king, loans were provided for earthquake effected people and earthquake volunteers groups were formed.
An emeritus Oregon State University geologist, who was one of the first scientists to point to the possibility of a major earthquake in the Pacific Northwest, outlines some of the world’s seismic “time bombs” in a forthcoming book.
One of those time bombs listed, in a segment he wrote last year, was Nepal where on April 25, an earthquake estimated at magnitude 7.8 struck the region, killing more than 7,500 people and injuring another 14,500.
Robert Yeats’ prescience is eerily familiar.
Five years ago, Yeats was interviewed by Scientific American on earthquake hazards and outlined the dual threats to Port au Prince, Haiti, of poverty and proximity to a major fault line. One week later, that time bomb went off and more than 100,000 people died in a catastrophic earthquake.
When the Scientific American reporter called Yeats after that seismic disaster to ask if he had predicted the quake, he said no.
“I could say where the time bombs are located – large, rapidly growing cities next to a tectonic plate boundary with a past history of earthquakes, but I had no way of knowing that the bomb would go off a week after my interview,” he said.
Fast forward to 2015 – Yeats has completed a new book, “Earthquake Time Bombs,” which will be published later this year by Cambridge University Press. In that book, he identifies other time bombs around the world; one is a region he has visited frequently in the past 30 years – the Himalayas, including Kathmandu, Nepal, a city of more than a million people.
Yeats points to several areas around the worlds where large cities lie on or adjacent to a major plate boundary creating a ticking time bomb: Tehran, the capital of Iran; Kabul in Afghanistan; Jerusalem in the Middle East; Caracas in Venezuela; Guantanamo, Cuba; Los Angeles, California; and the Cascadia Subduction Zone off the northwestern United States and near British Columbia.
“These places should take lessons from the regions that already have experienced major earthquakes, including Nepal,” said Yeats, who is with OSU’s College of Earth, Ocean, and Atmospheric Sciences.
Like Port au Prince, Kathmandu lies on a tectonic plate boundary – the thrust fault between the high Himalayas and the continent of India to the south. The plate began its northward movement 50 million years ago, Yeats said, and is progressing at the rate of about two-thirds of an inch a year. As the plate is forcing its way beneath Tibet, it is triggering periodic earthquakes along the way.
“It takes time to build up a sufficient amount of stress in these systems, but eventually they will rupture,” Yeats said. “The 2015 Nepal quake was, unquestionably, a disaster with losses of life in the thousands. But it could have been worse.”
“With the assistance of an American non-profit seismology group, the city of Kathmandu created a disaster management unit and a National Society for Earthquake Technology that established committees of citizens to raise awareness and upgrade buildings, especially public schools,” Yeats pointed out. “Other ‘time bombs’ would be wise to do the same.”
Making buildings more earthquake-resistant is imperative for cities near a fault, yet economics often preclude such measures. Yeats said some of the greatest losses in the Nepal quake took place in United Nations World Heritage sites of Bhaktapur and Patan, where ancient buildings had not been strengthened.
“We are not able to predict an earthquake, but we can identify potential trouble,” Yeats said. A seismic gap in the Himalayas was identified years ago by the late Indian seismologist K.N. Khattri in between western Himalaya of India and Kathmandu, where a magnitude 8.1 quake hit in 1934, he pointed out. The earthquake on April 25 struck within Khattri’s seismic gap, Yeats noted.
The 1934 earthquake killed an estimated 20 percent of the population of Kathmandu Valle, some 30,000 people. The population there was much smaller than it is today.
“The 1934 epicenter apparently was east of the city, whereas the epicenter of April 25’s earthquake was to the west, meaning that the two earthquakes may have ruptured different parts of the plate-boundary fault,” Yeats said.
Earlier earthquakes that damaged Kathmandu struck in 1833 and 1255. The location and magnitude of those two quakes are uncertain.
“Videos of this year’s earthquake focused on damaged and destroyed buildings and many of these were old historical buildings that had not been upgraded,” Yeats said. “Photos also showed new buildings that did not appear to be damaged. There’s a lesson there.”
Earthquakes off the east coast of Japan on 11 March 2011: Dotted circles indicate foreshocks, solid circles aftershocks. The size of the largest circle corresponds to the location of the epicenter of the main quake. Credit: NASA Earth Observatory
On 11 March 2011, a massive release of stress between two overlapping tectonic plates occurred beneath the ocean floor off the coast of Japan, triggering a giant tsunami. The Tohoku quake resulted in the death of more than 15,000 people, the partial or total destruction of nearly 400,000 buildings, and major damage to the Fukushima nuclear power plant. This “superquake” may have been the largest in a series of earthquakes, thus marking the end of what’s known as a supercycle: a sequence of several large earthquakes.
A research team at ETH Zurich headed by Taras Gerya, professor of geophysics, and Ylona van Dinther is studying supercycles such as this that occur in subduction zones. Geologists use the term “subduction zone” to refer to the boundary between two tectonic plates along a megathrust fault, where one plate underthrusts the other and moves into the earth’s mantle. These zones are found all over the world: off the South American coast, in the US’s Pacific Northwest, off Sumatra — and of course in Japan.
New explanation for gradual slip phenomen
However, earthquakes don’t occur at just any point along a megathrust fault, but only in the fault’s seismogenic zones. Why? In these zones, friction prevents relative movement of the plates over long periods of time. “This causes stresses to build up; an earthquake releases them all of a sudden,” explains ETH doctoral student Robert Herrendörfer. After the quake has released these stresses, the continued movement of the plates builds up new stresses, which are then released by new earthquakes — and an earthquake cycle is born. In a supercycle, the initial quakes rupture only parts of a subduction zone segment, whereas the final “superquake” affects the entire segment.
Several different theories have been advanced to explain this “gradual rupture” phenomenon, but they all assume that individual segments along the megathrust fault are governed by different frictional properties. “This heterogeneity results in a kind of ‘patchwork rug’,” says Herrendörfer. “To begin with, earthquakes rupture individual smaller patches, but later a ‘superquake’ ruptures several patches all at once.”
More supercycles in broad seismogenic zone
In a new article recently published in Nature Geoscience, Herrendörfer’s research group at ETH proposed a further explanation that doesn’t include this patchwork idea. Simply put: the wider a seismogenic zone, the greater the probability of a supercycle occurring.
To understand this, you first have to picture the physical forces at work in a subduction zone. As one plate dives beneath the other at a particular angle, the plates along the megathrust fault become partially coupled together, so the lower plate pulls the upper one down with it.
The ETH researchers ran computer simulations of this process, with the overriding plate represented by a wedge and the lower by a rigid slab. Since the plates are connected to each other only within the seismogenic zone, the wedge is deformed and physical stresses build up. In the adjacent earthquake-free zones, the plates can move relative to each other.
These stresses build up most rapidly at the edges of the seismogenic zone. If the stress there becomes greater than the plate’s frictional resistance, the wedge decouples from the lower plate and begins to move relative to the subducting plate. As the relative speed increases, the frictional resistance decreases — allowing the wedge to move even faster. The result is a rapid succession of interactions: an earthquake.
The earthquake spreads out, stopping only when it reaches a point where the frictional resistance is once again greater than the stress. That is where the slip event ends and both plates couple together again.
As part of his dissertation work, Herrendörfer has investigated how the width of the seismogenic zone affects this process. The models show that at the start of a supercycle, the difference between the stress and the frictional resistance is very large — and the wider the seismogenic zone, the larger the difference. “This means that the first earthquakes in this area will only partially rupture the seismogenic zone,” says Herrendörfer. In narrower zones, it takes just one earthquake to rupture the entire zone. In wider zones that are about 120 km or more across, the stress is released in a series of several quakes and ultimately in a superquake.
Models not suitable for predicting earthquakes
Empirical data supports this explanation. “To date, supercycles have been observed only in subduction zones with a larger-than-average seismogenic zone about 110 km across,” says Herrendörfer.
Based on their findings, the ETH researchers have defined further regions in addition to those already known as places that could be affected by supercycles — namely, the subduction zones off Kamchatka, the Antilles, Alaska and Java.
However, Herrendörfer cautions against jumping to conclusions. “Our theoretical models represent nature only to a limited extent, and aren’t suitable for predicting earthquakes,” he emphasises. “Our efforts were aimed at improving our understanding of the physical processes at work in an earthquake cycle. In future, this knowledge could be used for generating long-term estimates of the risk of earthquakes.” The method can also be applied to continental collision zones, such as the Himalayan mountain range, where Nepal was recently struck by a devastating quake.
How tectonic plates collide
Subduction zones are convergent boundaries of tectonic plates, areas where plates move towards and against each other. These convergent boundaries also include continental collision zones such as the Alps and the Himalayas, where the Indian plate is colliding with the Asian plate. Other plate boundaries are divergent, where the plates are moving away from each other, such as in Iceland. On transform plate boundaries, plates slide past each other horizontally on a vertical fault. Examples include the San Andreas Fault in California and Turkey’s North Anatolian Fault.
Reference:
Robert Herrendörfer, Ylona van Dinther, Taras Gerya, Luis Angel Dalguer. Earthquake supercycle in subduction zones controlled by the width of the seismogenic zone. Nature Geoscience, 2015; DOI: 10.1038/ngeo2427
Note: The above story is based on materials provided by ETH Zurich. The original article was written by Astrid Tomczak-Plewka.
The village of Chautara, Nepal as seen from space. Credit: Google Earth
Four men trapped under as much as 10 feet of bricks, mud and other debris have been rescued in Nepal thanks to a new search-and-rescue technology developed in partnership by the Department of Homeland Security’s (DHS) Science and Technology Directorate (S&T) and the National Aeronautics and Space Administration’s (NASA) Jet Propulsion Laboratory (JPL). The device called FINDER (Finding Individuals for Disaster and Emergency Response) uses microwave-radar technology to detect heartbeats of victims trapped in wreckage. Following the April 25 earthquake in Nepal, two prototype FINDER devices were deployed to support search and rescue teams in the stricken areas.
“The true test of any technology is how well it works in a real-life operational setting,” said DHS Under Secretary for Science and Technology Dr. Reginald Brothers. “Of course, no one wants disasters to occur, but tools like this are designed to help when our worst nightmares do happen. I am proud that we were able to provide the tools to help rescue these four men.”
The men had been trapped beneath the rubble for days in the hard-hit village of Chautara. David Lewis, president of one of S&T’s commercial partners, R4 Inc. out of Eatontown, N.J., arrived in Nepal with two prototype FINDER devices on April 29 to assist in the rescue efforts. He joined a contingent of international rescuers from China, the Netherlands, Belgium and members of the Nepali Army in Northern Nepal. Using FINDER, they were able to detect two heartbeats beneath each of two different collapsed structures, allowing the rescue workers to find and save the men.
“NASA technology plays many roles: driving exploration, protecting the lives of our astronauts and improving—even saving—the lives of people on Earth,” said Dr. David Miller, NASA’s chief technologist at NASA Headquarters in Washington. “FINDER exemplifies how technology designed for space exploration has profound impacts to life on Earth.”
The FINDER device will be demonstrated on Thursday, May 7, at the Virginia Task Force One Training Facility in Lorton, Va. At this event, which was scheduled long before the Nepali earthquake, S&T and JPL will demonstrate the technology with the assistance of members of Virginia Task Force One. They will also announce its official transition to commercial enterprise where the devices can be manufactured and made available to search and rescue teams around the world.
FINDER has previously demonstrated capabilities of detect people buried under up to 30 feet of rubble, hidden behind 20 feet of solid concrete, and from a distant of 100 feet in open spaces. A new “locator” feature has since been added to not only provide search and rescue responders with confirmation of a heartbeat, but also the approximate location of trapped individuals within about five feet, depending on the type of rubble.
This is a satellite image of Italy, courtesy NASA. Credit: NASA
Geological knowledge is essential for the sustainable development of a “smart city” — one that harmonizes with the geology of its territory. Making a city “smarter” means improving the management of its infrastructure and resources to meet the present and future needs of its citizens and businesses. In the May issue of GSA Today, geologist Donatella de Rita and classical archaeologist Chrystina Häuber explain this idea further by using early Rome and Naples as comparative examples.
The authors describe Rome prior to Republican Times as a smart city because its expansion did not substantially alter the natural features of the area, and natural resources were managed to minimize environmental risks. Rome, which had at that time an economy based on agriculture, developed on small hilltops, and its position on the Tiber alluvial plain ensured fertile soils and easy commerce between river banks. Farms were plentiful, even inside the city walls, ensuring the self-sustenance of the city. Rome was also favored by an abundance of water resources, such as the Tiber and Aniene Rivers, and several natural springs inside the city walls.
In contrast, during the same period, Naples was exposed to more geological hazards and had fewer natural resources. Naples was located within an easily defendable bay, and as such its economy was dominated by sea trade. The rugged geomorphology of Naples’ interior territory significantly limited agriculture and diversification. Rather than being able to expand outward, Naples mostly grew vertically, using as foundations the natural marine terraces bordering the coast. Geomorphology, therefore, played a key role in constraining the importance of Naples to the Roman Empire, according to de Rita and Häuber.
Over time, however, rapid urban expansion and concomitant population growth led to the overuse of resources and increased hazards for both cities, write de Rita and Häuber. As a result, the cities became unstable and fragile, with disasters resulting from several natural processes, such as flooding, volcanism, CO2 emissions, and earthquakes.
Reference:
Donatella de Rita, Chrystina Häuber. The smart city develops on geology: Comparing Rome and Naples. GSA Today, 2015; 4 DOI: 10.1130/GSATG222A.1
The modeled slip on the fault is shown as viewed from above and indicated by the colors and contours within the rectangle. The peak slip in the fault exceeds 19.7 feet (6 meters). The ground motion measured with GPS is shown by the red and purple arrows and was used to develop the fault slip model. Aftershocks are indicated by red dots. Background color and shaded relief reflect regional variations in topography. The barbed lines show where the main fault reaches Earth’s surface. Credit: NASA/JPL-Caltech
Using a combination of satellite radar imaging data, GPS data measured in and near Nepal, and seismic observations from instruments around the world, Caltech and JPL scientists have constructed a preliminary picture of what happened below Earth’s surface during the recent 7.8-magnitude Gorkha earthquake in Nepal.
The team’s observations and models of the April 25, 2015 earthquake, produced through the Advanced Rapid Imaging and Analysis (ARIA) project—a collaboration between Caltech and JPL—include preliminary estimates of the slippage of the fault beneath Earth’s surface that resulted in the deaths of thousands of people. In addition, the ARIA scientists have provided first responders and key officials in Nepal with information and maps that show block-by-block building devastation as well as measurements of ground movement at individual locations around the country.
“As the number of orbiting imaging radar and optical satellites that form the international constellation increases, the expected amount of time it takes to acquire an image of an impacted area will decrease, allowing for products such as those we have made for Nepal to become more commonly and rapidly available,” says Mark Simons, professor of geophysics at Caltech and a member of the ARIA team. “I fully expect that within five years, this kind of information will be available within hours of a big disaster, ultimately resulting in an ability to save more lives after a disaster and to make assessment and response more efficient in both developed and developing nations.”
Over the last five years, Simons and his colleagues in Caltech’s Seismological Laboratory and at JPL have been developing the approaches, infrastructure, and technology to rapidly and automatically use satellite-based observations to measure the movement of Earth’s surface associated with earthquakes, volcanoes, landslides and other geophysical processes.
“ARIA is ultimately aimed at providing tools and data—for use by groups ranging from first responders, to government agencies, and individual scientists—that can help improve situational awareness, response, and recovery after many natural disasters,” Simons says. “The same products also provide key observational constraints on our physical understanding of the underlying processes such as the basic physics controlling seismogenic behavior of major faults.”
Left: Illustration of Ottoia, a prehistoric priapulid, burrowing. Right: Ottoia worm. Credit: Left: Smokeybjb via Wikimedia Commons. Right: Martin Smith.
A new study of teeth belonging to a particularly phallic-looking creature has led to the compilation of a prehistoric ‘dentist’s handbook’ which may aid in the identification of previously unrecognised specimens from the Cambrian period, 500 million years ago.
It sounds like something out of a horror movie: a penis-shaped worm which was able to turn its mouth inside out and drag itself around by its tooth-lined throat, which resembled a cheese grater. But a new study of the rather unfortunately-named penis worm has found that their bizarre dental structure may help in the identification of previously unrecognised fossil specimens from the time on Earth when animals were first coming into their own.
Reconstructing the teeth of penis worms, or priapulids, in fine detail has enabled researchers from the University of Cambridge to compile a ‘dentist’s handbook’ which has aided in the identification of fossilised teeth from a number of previously-unrecognised penis worm species from all over the world. The results are published today (6 May) in the journal Palaeontology.
The researchers used electron microscopy to examine the internal structure of the teeth of these creatures, which first emerged during the ‘Cambrian explosion’, a period of rapid evolutionary development about half a billion years ago, when most major animal groups first appear in the fossil record.
The teeth of these Cambrian priapulids had different shapes according to their function: some were shaped like a cone fringed with tiny prickles and hairs, some were shaped like a bear claw, and some like a city skyline.
During the Cambrian, most animals were soft-bodied, like worms and sponges. Therefore, outside of the few very special places where conditions are just right to enable preservation of soft-bodied creatures, it is difficult to know for certain how far certain species were distributed across the Earth at the time.
“As teeth are the most hardy and resilient parts of animals, they are much more common as fossils than whole soft-bodied specimens,” said Dr Martin Smith, a postdoctoral researcher in Cambridge’s Department of Earth Sciences and the paper’s lead author. “But when these teeth – which are only about a millimetre long – are found, they are easily misidentified as algal spores, rather than as parts of animals. Now that we understand the structure of these tiny fossils, we are much better placed to a wide suite of enigmatic fossils.”
Both modern and Cambrian penis worms have spent their lives burrowing into the sediment beneath the ocean since they first appeared 500 million years ago.
During the Cambrian, penis worms were voracious predators, gobbling up anything that crossed their path, including worms, shrimp and other marine creatures. They were able to turn their mouths inside out to reveal a tooth-lined throat that looked like a prehistoric cheese grater.
These teeth were not just used for eating food, however. By turning their mouths inside out, penis worms could also use their teeth sort of like miniature grappling hooks, using them to grip a surface and then pull the rest of their bodies along behind.
“Modern penis worms have been pushed to the margins of life, generally living in extreme underwater environments,” said Smith. “But during the Cambrian, they were fearsome beasts, and extremely successful ones at that.”
For this study, the researchers examined fossils of Ottoia, a type of penis worm, about the length of a finger, which lived during the Cambrian. The fossils originated from the Burgess Shale in Western Canada, the world’s richest source of fossils from the period, full of weird and wacky-looking creatures that have helped scientists understand how animal life on Earth developed.
Using high resolution electron and optical microscopy, they were able to expose the curious structure of Ottoia’s teeth for the first time. By reconstructing the structure of these teeth in detail, the researchers were then able to identify fossilised teeth of a number of previously-unrecognised penis worm species from all over the world.
“Teeth hold all sorts of clues, both in modern animals and in fossils,” said Smith. “It’s entirely possible that unrecognised species await discovery in existing fossil collections, just because we haven’t been looking closely enough at their teeth, or in the right way.”
Reference:
Martin R. Smith, Thomas H. P. Harvey and Nicholas J. Butterfield, The macro- and microfossil record of the Cambrian priapulid Ottoia. Article first published online: 6 MAY 2015. DOI: 10.1111/pala.12168
