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Categories: Engineering: Graphene, Geoscience: Earthquakes

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Researchers have published a new theory for making batches of carbon nanotubes with a single, desired chirality. Their method could simplify purification of nanotubes that are all metallic or all semiconductors.

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Subduction zones, where one tectonic plate slides beneath another, produce the most devastating seismic, volcanic, and landslide hazards on the planet. A new report presents an ambitious plan to make major advances in understanding subduction zone hazards by bringing together a diverse community of scientists in a long-term collaborative effort, deploying new instrumentation in subduction zones, and developing more sophisticated and accurate models.

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Groundwater is considered both an environmental and industrial resource, but a new study indicates it is also an important resource in disaster prevention. Researchers conducted research surveys of 91 well owners and 328 welfare facilities affected by the 2016 Kumamoto Earthquake. The surveys clarified groundwater use following the earthquake and policy issues that could make the use of emergency wells more effective in the wake of future disasters. The surveys' findings provide useful data for city governments that have installed or are considering installing emergency wells.

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A recent study has proposed a strategy to synthesize single-crystalline graphite films orders of magnitude large, up to inch scale.

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Chemists and engineers have discovered a fundamental friction law that is leading to a deeper understanding of energy dissipation in friction and the design of two-dimensional materials capable of minimizing energy loss.

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Engineers synthesized aligned forests of nanoscale fibers made of boron nitride, or 'white graphene.' They hope to harness the technique to fabricate bulk-scale arrays of these nanotubes, which can then be combined with other materials to make stronger, more heat-resistant composites, for instance to shield space structures and hypersonic aircraft.

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About 14% of magnitude 6.7 or greater strike-slip earthquakes since 2000 have been supershear. That's 50% more than previously thought. Supershear earthquakes occur when a fault ruptures faster than seismic shear waves can travel through rock. The events were thought to be rare because scientists had mostly looked for them on land. The findings suggest that disaster planning assessments should include whether a fault is able to produce supershear quakes, which are potentially more destructive than other types.

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One natural disaster can knock out electric service to millions. A new study suggests that back-to-back disasters could cause catastrophic damage, but the research also identifies new ways to monitor and maintain power grids.

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Magma beneath long-dormant Mount Edgecumbe volcano in Southeast Alaska has been moving upward through Earth's crust, according to research the Alaska Volcano Observatory rapidly produced using a new method.

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Researchers have engineered a quantum box for polaritons in a 2D material, achieving large polariton densities and a partially 'coherent' quantum state. New insights from the novel technique could allow researchers to access striking 'collective' quantum phenomena in this material family, and enable ultra-energy efficient and high-performance future technologies. Laying a 'small' 2D material on top of a 'large' layer allowed the researchers to trap and investigate polaritons, comparing them with freely moving polaritons.

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Rapidly evolving floods are a major and growing hazard worldwide. Currently, their onset and evolution is hard to identify using existing systems. However, seismic sensors already in place to detect earthquakes could be a solution to this problem. Researchers show that a seismometer can sense a flood, such as the devastating one that hit Germany in July 2021, up to 1.5 km away. This could act as an early warning to save lives and lessen damage. They also found that being able to measure the 'seismic footprint' of the flood provides information on its magnitude, velocity and trajectory in real time, which could be used for future flood protection.

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A new large-scale analysis of hillslope connectivity at the continental scale was recently published. The study gives new understanding of mechanisms that determine how effectively hillslopes drive floods and landslides, as well as promote the presence of wetlands.

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An artificial-intelligence approach borrowed from natural-language processing -- much like language translation and autofill for text on your smart phone -- can predict future fault friction and the next failure time with high resolution in laboratory earthquakes. The technique, applying AI to the fault's acoustic signals, advances previous work and goes beyond by predicting aspects of the future state of the fault's physical system.

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Some 66 million years ago, a 10-kilometer asteroid hit Earth, triggering the extinction of the dinosaurs. New evidence suggests that the Chicxulub impact also triggered an earthquake so massive that it shook the planet for weeks to months after the collision. The amount of energy released in this 'mega-earthquake' is estimated at 10 to the exponent 23 joules, which is about 50,000 times more energy than was released in the magnitude 9.1 Sumatra earthquake in 2004.

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Trapped inside the shoreline of a bay, the resonant interactions of a tsunami with regular waves can prolong the tsunami disturbance. For the 2021 magnitude 7 Acapulco, Mexico earthquake and tsunami, edge waves in the bay and the short continental shelf also had a surprisingly significant effect on the tsunami's duration, according to a new study.

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Scientists who drilled deeper into an undersea earthquake fault than ever before have found that the tectonic stress in Japan's Nankai subduction zone is less than expected.  The findings are a puzzle but will help scientists home in on the link between tectonic forces and the earthquake cycle and potentially lead to better earthquake forecasts, both at Nankai and other megathrust faults such as Cascadia in the Pacific Northwest. The drilling reached over two miles into the Nankai subduction zone and was conducted in 2018 with the IODP scientific drilling vessel Chikyu.

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Researchers have demonstrated how a nanoscale layer of superconducting niobium nitride (NbNx) can be grown directly onto aluminum nitride (AIN). The arrangement of atoms, nitrogen content, and electrical conductivity were found to depend on growth conditions, particularly temperature, and the spacing of atoms in the two materials was sufficiently compatible to produce flat layers. The structural similarity between NbNx and AIN will facilitate the integration of superconductors into semiconductor optoelectronic devices.

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The carrier concentration and conductivity in p-type monovalent copper semiconductors can be significantly enhanced by adding alkali metal impurities. Doping with isovalent and larger-sized alkali metal ions effectively increased the free charge carrier concentration, and the mechanism was unraveled by their theoretical calculations. Their carrier doping technology enables high carrier concentration and high mobility p-type thin films to be prepared from the solution process, with photovoltaic device applications.

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It isn't every day that we learn something that fundamentally changes how we understand our world. But for volcanologists across the globe, such a revelation has occurred.

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Researchers demonstrated a topological insulator device that opens the way towards observing the quantum anomalous Hall effect. Because the currents generated are resistant to scattering, but very sensitive to applied magnetic fields, they may be used for reducing power consumption in computing applications.