bluuebunny/crossref_metadata_2025_split huggingface dataset:
Slip history of the 2016 Mw 7.0 Kumamoto earthquake: Intraplate rupture in complex tectonic environment
Authors: Hao Jinlai , Ji Chen , Yao Zhenxin 
Published: December 2016

AbstractRupture history of the 2016 Mw 7.0 Kumamoto earthquake is constrained by using the waveforms of strong motion observations, teleseismic broadband body waves, and long‐period surface waves. Its fault geometry is modeled with Hinagu (orienting 205° and dipping 73°) and Futagawa (orienting 235° and dipping 60°), two segments. The result reconciles the difference between moment tensor solutions and the surface fault trace. It reveals a complex rupture process that initiated on the Hinagu segment in dextral motion, propagated northeastward unilaterally, and after 15 s ceased near Aso volcano with normal fault motion. The average slip, rise time, and slip rate are 1.8 m, 2.0 s, and 1.2 m/s, respectively. The rupture broke through an ~30° fault intersection without notable delay, which can be a result of dynamic “unclamping.” The northeast boundary of the largest asperity might mark the bottom of the seismogenic zone, which becomes shallower gradually near Aso volcano.
Mass wasting on Phobos triggered by an evolving tidal environment
Authors: Shi X. , Oberst J. , Willner K. 
Published: December 2016

AbstractThe Martian moon Phobos is experiencing orbital decay, increasing tidal forces, and possible disruption in the near future. We suggest that this changing dynamic tidal environment has contributed to resurfacing of the odd‐shaped small moon. We investigated mass wasting features in craters using high‐resolution images acquired by the Mars Express on board High‐Resolution Stereo Camera. We model the evolving dynamical environment of Phobos by reconstructing dynamic slopes on its surface with Phobos at different distances to Mars. We note that the increase in slope by tidal effect correlates with most of the observed landslides, which is particularly obvious for craters near the sub‐Mars and anti‐Mars points. We suggest that the effect has triggered mass displacements that are responsible for observed asymmetries of some craters. The most recent landslides are likely to be geologically young and occurred within the past few hundred million years.
Contemporary glacier retreat triggers a rapid landslide response, Great Aletsch Glacier, Switzerland
Authors: Kos Andrew , Amann Florian , Strozzi Tazio , Delaloye Reynald , von Ruette Jonas , Springman Sarah 
Published: December 2016

AbstractThe destabilization and catastrophic failure of landslides triggered by retreating glaciers is an expected outcome of global climate change and poses a significant threat to inhabitants of glaciated mountain valleys around the globe. Of particular importance are the formation of landslide‐dammed lakes, outburst floods, and related sediment entrainment. Based on field observations and remote sensing of a deep‐seated landslide, located at the present‐day terminus of the Great Aletsch Glacier, we show that the spatiotemporal response of the landslide to glacier retreat is rapid, occurring within a decade. Our observations uniquely capture the critical period of increase in slope deformations, onset of failure, and show that measured displacements at the crown and toe regions of the landslide demonstrate a feedback mechanism between glacier ice reduction and response of the entire landslide body. These observations shed new light on the geomorphological processes of landslide response in paraglacial environments, which were previously understood to occur over significantly longer time periods.
The Mushroom: A half‐sky energetic ion and electron detector
Authors: Hill M. E. , Mitchell D. G. , Andrews G. B. , Cooper S. A. , Gurnee R. S. , Hayes J. R. , Layman R. S. , McNutt R. L. , Nelson K. S. , Parker C. W. , Schlemm C. E. , Stokes M. R. , Begley S. M. , Boyle M. P. , Burgum J. M. , Do D. H. , Dupont A. R. , Gold R. E. , Haggerty D. K. , Hoffer E. M. , Hutcheson J. C. , Jaskulek S. E. , Krimigis S. M. , Liang S. X. , London S. M. , Noble M. W. , Roelof E. C. , Seifert H. , Strohbehn K. , Vandegriff J. D. , Westlake J. H. 
Published: December 2016

AbstractWe present a time‐of‐flight mass spectrometer design for the measurement of ions in the ~30 keV to 10 MeV range for protons (up to ~40 MeV and ~150 MeV for He and heavy ions, respectively) and ~30 keV to 1 MeV range for electrons, covering half of the sky with 80 apertures. The instrument, known as the “Mushroom,” owing to its shape, solves the field of view problem for magnetospheric and heliospheric missions that employ three‐axis stabilized spacecraft, yet still require extended angular coverage; the Mushroom is also compatible with a spinning spacecraft. The most important new feature of the Mushroom is the method through which uncomplicated electrostatic optics and clean position sensing combine to permit many apertures to fit into a compact, low‐mass sensor head (or wedge), several of which (ideally eight) compose a full instrument. Most of the sensor head's volume is an empty, equipotential region, resulting in the modest 250 g mass of each 10‐aperture wedge. The Mushroom is capable of separating ion species across most of its energy range and angular field of view. For example, separation of the neighboring 3He and 4He isotopes is excellent; the full width at half maximum mass resolution has been measured to be 0.24 amu to 0.32 amu, respectively. Converting this to a Gaussian width σm in mass m, this represents a σm/m mass resolution better than 0.04. This separation is highly desirable for the flight program for which the first Mushroom was built, the Solar Probe Plus mission. More generally, we estimate the mass resolution to be σm/m ≈ 0.1, but this is energy, mass, and angularly dependent. We also discuss the solid‐state detector stack capability, which extends the energy range of protons and helium, with composition, to ~100 MeV.
Hybrid fluid‐particle simulation of whistler‐mode waves in a compressed dipole magnetic field: Implications for dayside high‐latitude chorus
Authors: da Silva C. L. , Wu S. , Denton R. E. , Hudson M. K. , Millan R. M. 
Published: December 2016

AbstractIn this work we present a methodology for simulating whistler‐mode waves self‐consistently generated by electron temperature anisotropy in the inner magnetosphere. We present simulation results using a hybrid fluid/particle‐in‐cell code that treats the hot, anisotropic (i.e., ring current) electron population as particles and the background (i.e., the cold and inertialess) electrons as fluid. Since the hot electrons are only a small fraction of the total population, warm (and isotropic) particle electrons are added to the simulation to increase the fraction of particles with mass, providing a more accurate characterization of the wave dispersion relation. Ions are treated as a fixed background of positive charge density. The plasma transport equations are coupled to Maxwell's equations and solved in a meridional plane (a 2‐D simulation with 3‐D fields). We use a curvilinear coordinate system that follows the topological curvature of Earth's geomagnetic field lines, based on an analytic expression for a compressed dipole magnetic field. Hence, we are able to simulate whistler wave generation at dawn (pure dipole field lines) and dayside (compressed dipole) by simply adjusting one scalar quantity. We demonstrate how, on the dayside, whistler‐mode waves can be locally generated at a range of high latitudes, within pockets of minimum magnetic field, and propagate equatorward. The obtained dayside waves (in a compressed dipole field) have similar amplitude and frequency content to their dawn sector counterparts (in a pure dipole field) but tend to propagate more field aligned.
GPS detection of the ionospheric disturbances over China due to impacts of Typhoons Rammasum and Matmo
Authors: Song Qian , Ding Feng , Zhang Xiaoxin , Mao Tian 
Published: December 2016

AbstractMedium‐scale traveling ionospheric disturbances (MSTIDs) possibly excited by typhoon have been presented, for the first time, by applying the two‐dimensional total electron content perturbation maps derived from the dense Global Position System (GPS) network in China. Two MSTIDs were observed on 19 July and 23 July 2014, respectively, during the landing phases of Typhoons Rammasun and Matmo. The MSTIDs excited by Rammasum were detected at 06:56–07:40 UT on 19 July 2014, with a mean horizontal phase velocity of 118 m/s and an amplitude of about 2 total electron content unit (TECU), 1 TECU = 1016 el m−2, it horizontally extended to about 600 km. The Matmo‐related MSTIDs were observed at 14:48–15:54 UT on 23 July 2014; the wavefront, perturbation amplitude, and the mean horizontal phase velocity were 1000 km, 1.8 TECU, and 132 m/s, respectively. Both MSTIDs propagated southwestward with a distance less than 200 km. The short propagation distances of the MSTIDs indicate that the MSTIDs may be caused by the body forces resulting from the typhoons.
Isotopically enriched N‐MORB: A new geochemical signature of off‐axis plume‐ridge interaction—A case study at 50°28′E, Southwest Indian Ridge
Authors: Yang A. Y. , Zhao T.‐P. , Zhou M.‐F. , Deng X.‐G. 
Published: December 2016

AbstractInteraction between the Southwest Indian Ridge (46°E and 52°20′E) and Crozet hotspot has been proposed by geophysical studies but remains controversial mostly due to the lack of E‐MORB (enriched mid‐ocean ridge basalts). Forty‐seven new samples collected from this region, including 15 from segment 27 centered at 50°28′E with a 10 km thick crust, are all N‐MORB (normal MORB) and can be classified into two groups: a high‐Al group only at 50°28′E and a Main group widespread. The former, with higher Al2O3 and lower TiO2 and SiO2, have slightly enriched Sr‐Nd‐Hf‐Pb isotopic compositions. We propose that their major and trace elemental signatures were modified by reaction with primitive cumulate in the crust, whereas the enriched isotopic compositions indicate the contribution of Crozet plume materials. During upslope flow of the Crozet plume to the ridge, decompression melting would occur along the path, which would deplete the plume in incompatible elements but not significantly change the isotopic compositions. Thus, when they finally reach the ridge, the depleted residue would remelt due to further decompression at MOR and produce isotopically enriched N‐MORB at segment 27. Isotopically enriched N‐MORB are known elsewhere, mostly at slower‐spreading ridges possibly influenced by plumes with large plume‐ridge distances. In particular, the constant Nd isotopic compositions with decreasing (La/Sm)N ratios for off‐axis magmatism between the Réunion hotspot toward the CIR perfectly match such a plume‐ridge interaction model. Therefore, aside from E‐MORB, isotopically enriched N‐MORB can also be considered as the geochemical signature for off‐axis plume‐ridge interaction.
Pore pressure behavior at the shut‐in phase and causality of large induced seismicity at Basel, Switzerland
Authors: Mukuhira Y. , Dinske C. , Asanuma H. , Ito T. , Häring M. O. 
Published: December 2016

AbstractInduced seismicity with unexpectedly large magnitude often occurs after shut‐in or end of stimulation, generating concerns at the end of stimulation. We investigated the physical mechanism of large‐magnitude induced seismicity during shut‐in following the hydraulic stimulation at Basel, Switzerland. Larger postinjection events occurred at the periphery of the seismic cloud. We estimated the pore pressure required to cause shear slip using Coulomb failure criteria from stress information, geometry of the fault planes of microseismic events, and a constant coefficient of friction. Time series analysis of pore pressure distribution indicated that pore pressure migrated to the far field even after shut‐in. Redistribution of pore pressure at shut‐in brought sufficient pore pressure increase to induce seismicity in the peripheral region. After shut‐in, the pore pressure gradient away from the well lessened and eventually pressure became uniform. These observations suggest that the higher pore pressure, which remained in the vicinity of the injection point, shifted to the farthest field. Shut‐in pressure migration caused uniform pore pressure distribution at the edge of the seismic zone. Shut‐in pressure destabilized a large part of the fault located at the edge of the seismic cloud, resulting in the shear slip of a large section of the fault. Meanwhile, during stimulation, only some parts of the fault entered the critical state because of the pressure gradient. The resulting shear slip on that specific part causes moderate magnitude events at most.
On the evolution of elastic properties during laboratory stick‐slip experiments spanning the transition from slow slip to dynamic rupture
Authors: Tinti E. , Scuderi M. M. , Scognamiglio L. , Di Stefano G. , Marone C. , Collettini C. 
Published: December 2016

AbstractThe physical mechanisms governing slow earthquakes remain unknown, as does the relationship between slow and regular earthquakes. To investigate the mechanism(s) of slow earthquakes and related quasi‐dynamic modes of fault slip we performed laboratory experiments on simulated fault gouge in the double direct shear configuration. We reproduced the full spectrum of slip behavior, from slow to fast stick slip, by altering the elastic stiffness of the loading apparatus (k) to match the critical rheologic stiffness of fault gouge (kc). Our experiments show an evolution from stable sliding, when k > kc, to quasi‐dynamic transients when k ~ kc, to dynamic instabilities when k < kc. To evaluate the microphysical processes of fault weakening we monitored variations of elastic properties. We find systematic changes in P wave velocity (Vp) for laboratory seismic cycles. During the coseismic stress drop, seismic velocity drops abruptly, consistent with observations on natural faults. In the preparatory phase preceding failure, we find that accelerated fault creep causes a Vp reduction for the complete spectrum of slip behaviors. Our results suggest that the mechanics of slow and fast ruptures share key features and that they can occur on same faults, depending on frictional properties. In agreement with seismic surveys on tectonic faults our data show that their state of stress can be monitored by Vp changes during the seismic cycle. The observed reduction in Vp during the earthquake preparatory phase suggests that if similar mechanisms are confirmed in nature high‐resolution monitoring of fault zone properties may be a promising avenue for reliable detection of earthquake precursors.
Interannual Arctic sea ice variability and associated winter weather patterns: A regional perspective for 1979–2014
Authors: Chen Hans W. , Alley Richard B. , Zhang Fuqing 
Published: December 2016

AbstractUsing Arctic sea ice concentration derived from passive microwave satellite observations in autumn and early winter over the 1979–2014 period, the Arctic region was objectively classified into several smaller regions based on the interannual sea ice variability through self‐organizing map analyses. The trend in regional sea ice extent (RSIE) in each region was removed using an adaptive, nonlinear, and nonstationary method called Ensemble Empirical Mode Decomposition, which captures well the accelerating decline of Arctic RSIEs in recent decades. Although the linear trend in RSIE is negative in all regions in both seasons, there are marked differences in RSIE trends and variability between regions, with the largest negative trends found during autumn in the Beaufort Sea, the Barents‐Kara Seas, and the Laptev‐East Siberian Seas. Winter weather patterns associated with the nonlinearly detrended RSIEs show distinct features for different regions and tend to be better correlated with the autumn than early winter RSIE anomalies. Sea ice losses in the Beaufort Sea and the Barents‐Kara Seas are both associated with a cooling of Eurasia, but in the former case the circulation anomaly is reminiscent of a Rossby wave train, whereas in the latter case the pattern projects onto the negative phase of the Arctic Oscillation. These results highlight the nonuniform changes in Arctic sea ice and suggest that regional sea ice variations may play a crucial role for the winter weather patterns.
Aerosol indirect effect dictated by liquid clouds
Authors: Christensen Matthew W. , Chen Yi‐Chun , Stephens Graeme L. 
Published: December 2016

AbstractAnthropogenic aerosols have been shown to enhance the solar reflection from warm liquid clouds and mask part of the warming due to the buildup of greenhouse gases. However, very little is known about the effects of aerosol on mixed‐phase stratiform clouds as well as other cloud regimes including cumulus, altocumulus, nimbostratus, deep convection, and anvil cirrus. These additional cloud categories are ubiquitous and typically overlooked in satellite‐based assessments of the global aerosol indirect forcing. Here we provide their contribution to the aerosol indirect forcing estimate using satellite data collected from several colocated sensors in the A‐train for the period 2006–2010. Cloud type is determined according to the 2B‐CLDCLASS‐LIDAR CloudSat product, and the observations are matched to the radiative flux measurements from CERES (Clouds and the Earth's Radiant Energy System) and aerosol retrievals from MODIS (MODerate resolution Imaging Spectroradiometer). The oceanic mean aerosol indirect forcing is estimated to be −0.20 ± 0.31 W m−2 with warm low‐level cloud largely dictating the strength of the response (−0.36 ± 0.21 W m−2) due to their abundance and strong cloud albedo effect. Contributions from mixed‐phase low‐level cloud (0.01 ± 0.06 W m−2) and convective cloud (0.15 ± 0.23 W m−2) are positive and buffer the system due to strong aerosol‐cloud feedbacks that reduce the cloud albedo effect and/or lead to convective invigoration causing a countering positive longwave warming response. By combining all major cloud categories together, aerosol indirect forcing decreases and now contains positive values in the uncertainty estimate.
Land‐atmosphere coupling in EURO‐CORDEX evaluation experiments
Authors: Knist Sebastian , Goergen Klaus , Buonomo Erasmo , Christensen Ole Bøssing , Colette Augustin , Cardoso Rita M. , Fealy Rowan , Fernández Jesús , García‐Díez Markel , Jacob Daniela , Kartsios Stergios , Katragkou Eleni , Keuler Klaus , Mayer Stephanie , van Meijgaard Erik , Nikulin Grigory , Soares Pedro M. M. , Sobolowski Stefan , Szepszo Gabriella , Teichmann Claas , Vautard Robert , Warrach‐Sagi Kirsten , Wulfmeyer Volker , Simmer Clemens 
Published: December 2016

AbstractInteractions between the land surface and the atmosphere play a fundamental role in the weather and climate system. Here we present a comparison of summertime land‐atmosphere coupling strength found in a subset of the ERA‐Interim‐driven European domain Coordinated Regional Climate Downscaling Experiment (EURO‐CORDEX) model ensemble (1989–2008). Most of the regional climate models (RCMs) reproduce the overall soil moisture interannual variability, spatial patterns, and annual cycles of surface exchange fluxes for the different European climate zones suggested by the observational Global Land Evaporation Amsterdam Model (GLEAM) and FLUXNET data sets. However, some RCMs differ substantially from FLUXNET observations for some regions. The coupling strength is quantified by the correlation between the surface sensible and the latent heat flux, and by the correlation between the latent heat flux and 2 m temperature. The first correlation is compared to its estimate from the few available long‐term European high‐quality FLUXNET observations, and the latter to results from gridded GLEAM data. The RCM simulations agree with both observational datasets in the large‐scale pattern characterized by strong coupling in southern Europe and weak coupling in northern Europe. However, in the transition zone from strong to weak coupling covering large parts of central Europe many of the RCMs tend to overestimate the coupling strength in comparison to both FLUXNET and GLEAM. The RCM ensemble spread is caused primarily by the different land surface models applied, and by the model‐specific weather conditions resulting from different atmospheric parameterizations.
Frequency spectra and vertical profiles of wind fluctuations in the summer Antarctic mesosphere revealed by MST radar observations
Authors: Sato Kaoru , Kohma Masashi , Tsutsumi Masaki , Sato Toru 
Published: December 2016

AbstractContinuous observations of polar mesosphere summer echoes at heights from 81–93 km were performed using the first Mesosphere‐Stratosphere‐Troposphere/Incoherent Scatter radar in the Antarctic over the three summer periods of 2013/2014, 2014/2015, and 2015/2016. Power spectra of horizontal and vertical wind fluctuations, and momentum flux spectra in a wide‐frequency range from (8 min)−1 to (20 days) −1 were first estimated for the Antarctic summer mesosphere. The horizontal (vertical) wind power spectra obey a power law with an exponent of approximately −2 (−1) at frequencies higher than the inertial frequency of (13 h)−1 and have isolated peaks at about 1 day and a half day. In addition, an isolated peak of a quasi‐2 day period is observed in the horizontal wind spectra but is absent from the vertical wind spectra, which is consistent with the characteristics of a normal‐mode Rossby‐gravity wave. Zonal (meridional) momentum flux spectra are mainly positive (negative), and large fluxes are observed in a relatively low‐frequency range from (1 day)−1 to (1 h)−1. A case study was performed to investigate vertical profiles of momentum fluxes associated with gravity waves and time mean winds on and around 3 January 2015 when a minor stratospheric warming occurred in the Northern Hemisphere. A significant momentum flux convergence corresponding to an eastward acceleration of ~200 m s−1 d−1 was observed before the warming and became stronger after the warming when mean zonal wind weakened. The strong wave forcing roughly accorded with the Coriolis force of mean meridional winds.
Quaternary Ammonium Salt‐Promoted Multi‐Component Reaction in Water: Access to 3‐Alkyl‐2, 3‐Dihydro‐1H‐Isoindolin‐1‐One Derivatives
Authors: Han Fu‐Zhong , Su Bo‐Bo , Jia Li‐Na , Wang Peng‐Wei , Hu Xiang‐Ping 
Published: December 2016

AbstractA concise synthesis of alkyl‐2,3‐dihydro‐1H‐isoindolin‐1‐one derivatives from 2‐formyl benzoic acid, β‐keto acid, and ammonia or primary amine was developed via a quaternary ammonium salt‐promoted multi‐component sequence of decarboxylative alkylation/lactamization reaction in water, in which the target products were obtained in good to excellent yields.magnified image
One‐Pot Two‐Step Synthesis of Optically Active α‐Amino Phosphonates by Palladium‐Catalyzed Hydrogenation/Hydrogenolysis of α‐Hydrazono Phosphonates
Authors: Goulioukina Nataliya S. , Shergold Ilya A. , Rybakov Victor B. , Beletskaya Irina P. 
Published: December 2016

AbstractAn efficient and convenient one‐pot procedure for the stereoselective catalytic synthesis of ring‐substituted [amino(phenyl)methyl]phosphonates has been developed. The enantioselective hydrogenation of easily available diisopropyl (Z)‐[aryl(phenylhydrazono)methyl]phosphonates using palladium(II) acetate as a precatalyst, (R)‐2,2′‐bis(diphenylphosphino)‐5,5′‐dichloro‐6,6′‐dimethoxy‐1,1′‐biphenyl [(R)‐Cl–MeO‐BIPHEP] as a ligand, and (1S)‐(+)‐10‐camphorsulfonic acid as an activator in a mixture of 2,2,2‐trifluoroethanol and methylene chloride at ambient temperature results in the formation of corresponding [aryl(2‐phenylhydrazino)methyl]phosphonates. The subsequent cleavage of the N−N bond has been accomplished with molecular hydrogen after the addition of palladium on carbon and methanol into crude reaction mixture to afford the optically active [amino(aryl)methyl]phosphonates. The method is operationally simple and provides an appreciable enantioselectivity up to 98 % ee.magnified image