ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    Unknown
    Hypocenter migration and crustal seismic velocity distribution observed for the inland earthquake swarms induced by the 2011 Tohoku-Oki earthquake in NE Japan: implications for crustal fluid distribution and crustal permeability (2014)
    Wiley
    In: Geofluids
    Details
    Publication Date: 2014-10-01
    Description: After the occurrence of the 2011 magnitude 9 Tohoku earthquake, the seismicity in the overriding plate changed. The seismicity appears to form distinct belts. From the spatiotemporal distribution of hypocenters, we can quantify the evolution of seismicity after the 2011 Tohoku earthquake. In some earthquake swarms near Sendai (Nagamachi-Rifu fault), Moriyoshi-zan volcano, Senya fault, and the Yamagata–Fukushima border (Aizu-Kitakata area, west of Azuma volcano), we can observe temporal expansion of the focal area. This temporal expansion is attributed to fluid diffusion. Observed diffusivity would correspond to the permeability of about 10 −15 (m 2 ). We can detect the area from which fluid migrates as a seismic low-velocity area. In the lower crust, we found seismic low-velocity areas, which appear to be elongated along N–S or NE–SW, the strike of the island arc. These seismic low-velocity areas are located not only beneath the volcanic front but also beneath the fore-arc region. Seismic activity in the upper crust tends to be high above these low-velocity areas in the lower crust. Most of the shallow earthquakes after the 2011 Tohoku earthquake are located above the seismic low-velocity areas. We thus suggest fluid pressure changes are responsible for the belts of seismicity. Temporal expansion of the focal area in some earthquake swarms near Sendai (Nagamachi-Rifu fault), Moriyoshi-zan volcano, Senya fault, and the Yamagata-Fukushima border (Aizu-Kitakata area, west of Azuma volcano) induced by the 2011 Tohoku-Oki earthquake was observed. This temporal expansion can be explained by fluid diffusion. We found seismic low-velocity areas, which is the possible areas with fluid, beneath the swarms. From the results, the induced earthquakes are thought to be affected by the possible fluid pressure change.
    Print ISSN: 1468-8115
    Electronic ISSN: 1468-8123
    Topics: Geosciences
    Published by Wiley
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 2
    facet.materialart.
    Unknown
    Featureless spectra on the Moon as evidence of residual lunar primordial crust (2015)
    Wiley
    Details
    Publication Date: 2015-11-26
    Description: We report the global distribution of areas exhibiting no absorption features (featureless or FL) on the lunar surface, based on the reflectance spectral data set obtained by the Spectral Profiler onboard Kaguya/SELENE. We found that FL sites are located in impact basins and large impact craters in the Feldspathic Highlands Terrane (FHT), while there are no FL sites in the Procellarum regions nor the South Pole–Aitken basin. FL sites in each impact basin/crater are mainly found at the peak rings or rims, where the purest anorthosite (PAN) sites are also found. At the local scale, most of the FL and PAN points are associated with impact craters and peaks. Most of the FL spectra show a steeper (redder) continuum than the PAN spectra, suggesting the occurrence of space weathering effects. We propose that most of the material exhibiting a FL spectrum originate from space weathered PAN. Taking into account all the occurrence trends of FL sites on the Moon, we propose that both the FL and PAN materials were excavated from the primordial lunar crust during ancient basin formations below the megaregolith in the highlands. Since the FL and PAN sites are widely distributed over the lunar surface, our new data may support the existence of a massive PAN layer below the lunar surface.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 3
    facet.materialart.
    Unknown
    Application of particle method to the casting process simulation (2012)
    Institute of Physics (IOP)
    Details
    Publication Date: 2012-07-04
    Description: Casting processes involve many significant phenomena such as fluid flow, solidification, and deformation, and it is known that casting defects are strongly influenced by the phenomena. However the phenomena complexly interacts each other and it is difficult to observe them directly because the temperature of the melt and other apparatus components are quite high, and they are generally opaque; therefore, a computer simulation is expected to serve a lot of benefits to consider what happens in the processes. Recently, a particle method, which is one of fully Lagrangian methods, has attracted considerable attention. The particle methods based on Lagrangian methods involving no calculation lattice have been developed rapidly because of their applicability to multi-physics problems. In this study, we combined the fluid flow, heat transfer and solidification simulation programs, and tried to simulate various casting processes such as continuous casting, centrifugal casting and ingot m...
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Institute of Physics (IOP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 4
    facet.materialart.
    Unknown
    Massive layer of pure anorthosite on the Moon (2012)
    Wiley
    Details
    Publication Date: 2012-07-06
    Description: We present a new global survey of the purest anorthosite (PAN) rock using the Spectral Profiler onboard Kaguya. We found that PAN rocks are widely distributed over the Moon, including the Feldspathic Highland Terrain and the south and north polar regions. All PAN sites are associated with huge impact structures with diameters larger than 100 km. Based on the global distributions of PAN and olivine-rich sites, we propose the existence of a massive PAN layer with a thickness of ∼50 km below an uppermost mafic-rich mixed layer with a thickness of ∼10 km. Below the PAN layer, a lower crustal layer with olivine-rich materials may be present on the nearside, but not on the far side of the Moon. The existence of a PAN layer with a thickness of ∼50 km suggests an Al2O3 abundance of 33 to 34 wt.% in the lunar crust, which is higher than previous estimates of
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 5
    facet.materialart.
    Unknown
    The widespread occurrence of high-calcium pyroxene in bright-ray craters on the Moon and implications for lunar-crust composition (2011)
    Wiley
    Details
    Publication Date: 2011-09-08
    Description: We investigated the continuous spectral features of fresh craters on the Moon accompanied by distinctive bright rays, with cavity diameters between 8 and 24 km. We used the data from the Spectral Profiler onboard SELENE (Kaguya) to gain a better understanding of the composition of the lunar highland crust. We found that the observed spectra exhibited strong symmetric absorption around 1 μm and recognizable absorption around 1.3 μm. The spectra around a few craters showed a drastic change in the relative strengths of these two absorption bands s1.3/1.0 at different locations in and around the craters, indicating differences in the abundance of plagioclase and mafic minerals. In contrast, the spectra around most of the craters showed no significant variation in spectral shape, with an essentially constant s1.3/1.0. We analyzed the absorption features of the craters with an essentially constant s1.3/1.0 using the Modified Gaussian Model. We found that the strongest symmetric absorption bands were centered at 0.97–1.01 μm with s1.3/1.0 ≈ 0.2–0.6. Comparing these values with data from known samples, we concluded that high-calcium pyroxene (HCP) is the most plausible dominant mafic mineral identified from the observed spectra. The fact that we detected such HCP-dominant spectra among rayed craters widely spaced across the lunar highland implies that the major mafic component of some portions of the lunar crust is HCP rather than low-calcium pyroxene (LCP).
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 6
    facet.materialart.
    Unknown
    Global occurrence trend of high-Ca pyroxene on lunar highlands and its implications (2015)
    Wiley
    Details
    Publication Date: 2015-03-25
    Description: We present details of the global distribution of high-Ca pyroxene (HCP)-rich sites in the lunar highlands based on the global dataset of hyper-spectral reflectance obtained by the SELENE Spectral Profiler. Most HCP-rich sites in the lunar highlands are found at fresh impact craters. In each crater, most of the detection points are distributed on the ejecta, rim, and floor of the impact craters rather than the central peaks, while the central peaks are dominated by purest anorthosite (PAN). This indicates that HCP-rich materials originate from relatively shallower regions of the lunar crust than PAN. In addition, while all ray craters with sizes larger than ~40km possess HCP-rich materials, small fresh craters with sizes less than ~6−−10km do not, indicating that the uppermost mixing layers in the lunar crust are not dominated by HCP. Based on these results, we propose that in the upper lunar crust, a HCP-rich zone overlying the PAN layer exists below the uppermost mixing layer. This HCP-rich zone may originate from interstitial melt during the formation of the flotation anorthositic cumulate, while an impact ejecta origin, impact melt origin, and/or magmatic intrusion into the upper lunar crust may also account for the occurrence of HCP-rich sites in the highlands.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 7
    facet.materialart.
    Unknown
    Variation of the lunar highland surface roughness at baseline 0.15–100 km and the relationship to relative age (2014)
    Wiley
    Details
    Publication Date: 2014-03-12
    Description: We report the surface roughness analysis of the lunar highlands for the baseline range 0.15–100 km. We use the Median Differential Slope α m to investigate the scale dependency of the roughness and derive the global α m distribution from SELENE Laser Altimeter and Terrain Camera data. While α m ( l ) versus baseline l (km) plots vary among different highland types, all highlands commonly show a peak at 3–30 km. The Pre-Nectarian surface shows a relatively large α m (20–30 km). Our analysis is supported by the simulation of synthetic surface cratering models and crater statistics. In our simulation, a peak of α m (30 km) is successfully reproduced. The actual crater density shows good correlation with an empirical roughness indicator. However, a large part of the Nectarian surface shows a peak at 6–9 km baseline. This peak may be caused by secondary craters and ejecta deposit textures from the Nectarian system basins.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 8
    facet.materialart.
    Unknown
    Numerical Analysis on the Vortex Pattern and Flux Particle Dispersion in KR Method Using MPS Method (2015)
    Institute of Physics (IOP)
    Details
    Publication Date: 2015-06-12
    Description: The mechanically-stirring vessel is widely used in many fields, such as chemical reactor, bioreactor, and metallurgy, etc. The type of vortex mode that formed during impeller stirring has great effect on stirring efficiency, chemical reacting rate and air entrapment. Many efforts have been made to numerically simulate the fluid flow in the stirring vessel with classical Eulerian method. However, it is difficult to directly investigate the vortex mode and flux particle dispersion. Therefore, moving particle semi-implicit (MPS) method, which is based on Lagrangian method, is applied to simulate the fluid flow in a KR method in this practice. Top height and bottom heights of vortex surface in a steady state under several rotation speed was taken as key parameters to compare the results of numerical and published results. Flux particle dispersion behaviour under a rotation speed range from 80 to 480 rpm was also compared with the past study. The result shows that the numerical calcul...
    Print ISSN: 1757-8981
    Electronic ISSN: 1757-899X
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Institute of Physics (IOP)
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 9
    facet.materialart.
    Unknown
    A new type of pyroclastic deposit on the Moon containing Fe-spinel and chromite (2013)
    Wiley
    Details
    Publication Date: 2013-07-26
    Description: [1]  We present details of the identification of sites that show an absorption band at visible wavelengths and a strong 2  μ m band using the SELENE Spectral Profiler. All the sites exhibiting the visible feature are found on the regional dark mantle deposit (DMD) at Sinus Aestuum. All the instances of the visible feature show a strong 2- μ m band, suggestive of Fe- and Cr-rich spinels, which are different from previously-detected Mg-rich spinel. Since no visible feature is observed in other DMDs, the DMD at Sinus Aestuum is unique on the Moon. The occurrence trend of the spinels at Sinus Aestuum is also different from that of the Mg-rich spinels, which are associated with impact structures. This may suggest that the spinel at Sinus Aestuum is a different origin from that of the Mg-rich spinel.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
  • 10
    facet.materialart.
    Unknown
    Seismic Wavefield Imaging of Long-Period Ground Motion in the Tokyo Metropolitan Area, Japan (2017)
    Wiley
    Details
    Publication Date: 2017-07-08
    Description: Long-period ground motions due to large earthquakes can cause devastating disasters, especially in urbanized areas located on sedimentary basins. To assess and mitigate such damage, it is essential to rapidly evaluate seismic hazards for infrastructures, which can be simulated by seismic response analyses that use waveforms at the base of each infrastructure as an input ground motion. The present study reconstructs the seismic wavefield in the Tokyo metropolitan area located on the Kanto sedimentary basin, Japan, from seismograms of the Metropolitan Seismic Observation network (MeSO-net). The obtained wavefield fully explains the observed waveforms in the frequency band of 0.10–0.20 Hz. This is attributed to the seismic wavefield imaging technique proposed by Kano et al . [2017], which implements the replica exchange Monte Carlo method to simultaneously estimate model parameters related to the subsurface structure and source information. Further investigation shows that the reconstructed seismic wavefield lower than 0.30 Hz is of high quality in terms of variance reduction, which quantifies a misfit in waveforms, but that the variance reduction rapidly worsens in higher frequencies. Meanwhile, the velocity response spectra show good agreement with observations up to 0.90 Hz in terms of the combined goodness-of-fit, which is a measure of misfit in the velocity response spectra. Inputting the reconstructed wavefield into seismic response analyses, we can rapidly assess the overall damage to infrastructures immediately after a large earthquake.
    Print ISSN: 0148-0227
    Topics: Geosciences , Physics
    Published by Wiley on behalf of American Geophysical Union (AGU).
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    PAPER CURRENT
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...