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41.
Y. Katsui S. Aramaki S. Matsuo O. Oshima T. Tiba Y. Sawada 《Bulletin of Volcanology》1990,52(Z1):i-vi
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Shunichi Koshimura Toshitaka Katada Harold O. Mofjeld Yoshiaki Kawata 《Natural Hazards》2006,39(2):265-274
This study develops a method for estimating the number of casualties that may occur while people evacuate from an inundation
zone when a tsunami has inundated an area. The method is based on a simple model of hydrodynamic forces as they affect the
human body. The method uses a Tsunami casualty index (TCI) computed at each grid point of a numerical tsunami model to determine
locations and times within the tsunami inundation zone where evacuation during the tsunami inundation is not possible and
therefore where casualties are likely to occur. The locations and times can be combined with information about population
density to compute the potential number of casualties. This information is useful in developing tsunami evacuation routes
that avoid such locations. To illustrate the method, it is applied to the Seattle waterfront in Washington State, USA, that
is under the threat of possible tsunami disasters due to Seattle Fault earthquakes. Preliminary results suggest that the tsunami
casualties may occur within the Seattle waterfront for 15 min, during the time interval from 3 to 18 min after a large Seattle
Fault tsunami is generated when the background tide level is mean high water. 相似文献
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S. M. White K. Iwai N. M. Phillips R. E. Hills A. Hirota P. Yagoubov G. Siringo M. Shimojo T. S. Bastian A. S. Hales T. Sawada S. Asayama M. Sugimoto R. G. Marson W. Kawasaki E. Muller T. Nakazato K. Sugimoto R. Brajša I. Skokić M. Bárta S. Kim A. J. Remijan I. de Gregorio S. A. Corder H. S. Hudson M. Loukitcheva B. Chen B. De Pontieu G. D. Fleishmann D. E. Gary A. Kobelski S. Wedemeyer Y. Yan 《Solar physics》2017,292(7):88
The Atacama Large Millimeter/submillimeter Array (ALMA) radio telescope has commenced science observations of the Sun starting in late 2016. Since the Sun is much larger than the field of view of individual ALMA dishes, the ALMA interferometer is unable to measure the background level of solar emission when observing the solar disk. The absolute temperature scale is a critical measurement for much of ALMA solar science, including the understanding of energy transfer through the solar atmosphere, the properties of prominences, and the study of shock heating in the chromosphere. In order to provide an absolute temperature scale, ALMA solar observing will take advantage of the remarkable fast-scanning capabilities of the ALMA 12 m dishes to make single-dish maps of the full Sun. This article reports on the results of an extensive commissioning effort to optimize the mapping procedure, and it describes the nature of the resulting data. Amplitude calibration is discussed in detail: a path that uses the two loads in the ALMA calibration system as well as sky measurements is described and applied to commissioning data. Inspection of a large number of single-dish datasets shows significant variation in the resulting temperatures, and based on the temperature distributions, we derive quiet-Sun values at disk center of 7300 K at \(\lambda = 3~\mbox{mm}\) and 5900 K at \(\lambda = 1.3~\mbox{mm}\). These values have statistical uncertainties of about 100 K, but systematic uncertainties in the temperature scale that may be significantly larger. Example images are presented from two periods with very different levels of solar activity. At a resolution of about \(25''\), the 1.3 mm wavelength images show temperatures on the disk that vary over about a 2000 K range. Active regions and plages are among the hotter features, while a large sunspot umbra shows up as a depression, and filament channels are relatively cool. Prominences above the solar limb are a common feature of the single-dish images. 相似文献
44.
Hideaki Yanagisawa Shunichi Koshimura Kazuhisa Goto Toyohiko Miyagi Fumihiko Imamura Anat Ruangrassamee Charlchai Tanavud 《Estuarine, Coastal and Shelf Science》2009
Using an integrated approach including satellite imagery analysis, field measurements, and numerical modeling, we investigated the damage to mangroves caused by the 2004 Indian Ocean tsunami at Pakarang Cape in Pang Nga Province, Thailand. Comparing pre- and post-tsunami satellite imagery of the study area, we found that approximately 70% of the mangrove forest was destroyed by the tsunami. Based on field observations, we found that the survival rate of mangroves increased with increasing stem diameter. Specifically, we found that 72% of Rhizophora trees with a 25–30 cm stem diameter survived the tsunami impact, whereas only 19% with a 15–20 cm stem diameter survived. We simulated the 2004 Indian Ocean tsunami using the nonlinear shallow-water wave theory to reproduce the tsunami inundation flow and investigated the bending moment acting on the mangrove trees. Results of the numerical model showed that the tsunami inundated areas along the mangrove creeks, and its current velocity reached 5.0 m s−1. Based on the field measurements and numerical results, we proposed a fragility function for mangroves, which is the relationship between the probability of damage and the bending stress caused by the maximum bending moment. We refined the numerical model to include the damage probability of mangrove forests using the obtained fragility function to investigate the tsunami reduction effect of mangrove forest. Under simple numerical conditions related to the mangrove forest, ground level, and incident wave, the model showed that a mangrove forest of Rhizophora sp. with a density of 0.2 trees m−2 and a stem diameter of 15 cm in a 400 m wide area can reduce the tsunami inundation depth by 30% when the incident wave is assumed to have a 3.0 m inundation depth and a wave period of 30 min at the shoreline. However, 50% of the mangrove forest is destroyed by a 4.5 m tsunami inundation depth, and most of the mangrove forest is destroyed by a tsunami inundation depth greater than 6 m. The reduction effect of tsunami inundation depth decreased when the tsunami inundation depth exceeded 3 m, and was mostly lost when the tsunami inundation depth exceeded 6 m. 相似文献
45.
Wakana Iwakami Naofumi Ohnishi Kei Kotake Shoichi Yamada Keisuke Sawada 《Astrophysics and Space Science》2009,322(1-4):43-47
The study of standing accretion shock instability (SASI) in core-collapse supernova cores has been done with three-dimensional (3D) computer simulations. Rotations with various perturbations were introduced from outer boundary of an initial steady accreting flow. We found that one or two armed spiral accreting flow onto the proto-neutron star (PNS) is formed inside the shock wave depending on perturbations. The linear growth of spiral modes are clearly diagnosed by the mode analysis of the shock surface, and the lower m modes grow quickly in the linear regime. 相似文献
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M. Shimojo T. S. Bastian A. S. Hales S. M. White K. Iwai R. E. Hills A. Hirota N. M. Phillips T. Sawada P. Yagoubov G. Siringo S. Asayama M. Sugimoto R. Brajša I. Skokić M. Bárta S. Kim I. de Gregorio-Monsalvo S. A. Corder H. S. Hudson S. Wedemeyer D. E. Gary B. De Pontieu M. Loukitcheva G. D. Fleishman B. Chen A. Kobelski Y. Yan 《Solar physics》2017,292(7):87
Observations of the Sun at millimeter and submillimeter wavelengths offer a unique probe into the structure, dynamics, and heating of the chromosphere; the structure of sunspots; the formation and eruption of prominences and filaments; and energetic phenomena such as jets and flares. High-resolution observations of the Sun at millimeter and submillimeter wavelengths are challenging due to the intense, extended, low-contrast, and dynamic nature of emission from the quiet Sun, and the extremely intense and variable nature of emissions associated with energetic phenomena. The Atacama Large Millimeter/submillimeter Array (ALMA) was designed with solar observations in mind. The requirements for solar observations are significantly different from observations of sidereal sources and special measures are necessary to successfully carry out this type of observations. We describe the commissioning efforts that enable the use of two frequency bands, the 3-mm band (Band 3) and the 1.25-mm band (Band 6), for continuum interferometric-imaging observations of the Sun with ALMA. Examples of high-resolution synthesized images obtained using the newly commissioned modes during the solar-commissioning campaign held in December 2015 are presented. Although only 30 of the eventual 66 ALMA antennas were used for the campaign, the solar images synthesized from the ALMA commissioning data reveal new features of the solar atmosphere that demonstrate the potential power of ALMA solar observations. The ongoing expansion of ALMA and solar-commissioning efforts will continue to enable new and unique solar observing capabilities. 相似文献
49.
Forbidden reflections of some pyroxenes described as having a lower symmetry than Pbca or C2/c have been examined, mainly using the detailed ψ-scanning method of the four-circle automated diffractometer. All reflections violating the systematic absences of Pbca orthopyroxene, C2/c spodumene, P2/n omphacite and P21/c pigeonite were found to be due to the Umweganregung process of multiple diffraction; the Umweganregung peaks observed for the ψ azimuth were indexed in terms of a four-circle geometry. Thus, the space groups of orthopyroxene, α spodumene, low omphacite and low pigeonite were confirmed to be Pbca, C2/c, P2/n and P21/c, respectively. 相似文献
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