Automatic detection of earthquake-induced ground failure effects through Faster R-CNN deep learning-based object detection using satellite images     

Hacıefendioğlu  Kemal  Başağa  Hasan Basri  Demir  Gökhan 《Natural Hazards》2021,105(1):383-403

Natural Hazards - The seismically induced ground failure is defined as any earthquake-generated process that leads to deformations within a soil medium, which in turn results in permanent...  相似文献   

Wave attenuation in the marginal ice zone during LIMEX     

Antony K. Liu  Paris W. Vachon  Chin Y. Peng  A.S. Bhogal 《大气与海洋》2013,51(2):192-206

Abstract

During the Labrador Ice Margin Experiments, LIMEX ‘87 in March 1987 and LIMEX ‘89 in March and April 1989, the Canada Centre for Remote Sensing (CCRS) CV‐580 aircraft collected synthetic aperture radar (SAR) image data over the marginal ice zone off the east coast of Newfoundland, Canada. One aspect of these experimental programs was the observation of ocean waves penetrating into the marginal ice zone (MIZ). Based upon directional wavenumber spectra derived from SAR image data, the wave attenuation rate is estimated using SAR image spectra and compared with predictions from a model developed by Liu and Mollo‐Christensen (1988). The wave and ice conditions were considerably different in LIMEX ‘87 and LIMEX ‘89. However, the model‐data comparisons are very good for all ice conditions observed. Both the model and the SAR‐derived wave attenuation rates show a characteristic roll‐over at high wavenumbers. A model for the eddy viscosity is proposed, using dimensional analysis, as a simple function of ice roughness and wave‐induced velocity. Eddy viscosities derived from SAR and wave buoy data for the wave attenuation rate show a trend that is consistent with the proposed model.  相似文献   

Iron site geometry in orthopyroxene: Multiple scattering calculations and XANES study     

Eleonora Paris  Trevor A. Tyson 《Physics and Chemistry of Minerals》1994,21(5):299-308

The iron site geometry in orthopyroxenes (OPX) and synthetic FeO, has been investigated by X-ray Absorption Near Edge Structure (XANES) spectroscopy. Multiple scattering calculations have been used to determine how the iron polyhedral geometry affects the absorption spectra. The results reported here demonstrate that this approach is effective in determining the site geometry around the absorbing atom, allowing the assignment of features in the XANES spectrum to specific structural aspects of the coordination environment. In the case of the orthopyroxenes this method allows discrimination between the multiple scattering contributions to the absorption spectrum due to the two octahedral sites M1 and M2 of the OPX structure. The results obtained with the MS calculation were used to evaluate the effects of polyhedral distortion, symmetry changes and iron site occupancies on the experimental spectra. The results indicate a more quantitative way to interpret XANES experimental spectra and give insights into the interpretation of site geometries of more complex or unknown structures and amorphous materials.  相似文献   

吉林浑江铅锌矿荒沟山区韧性剪切带特征及其控矿规律          下载免费PDF全文

张宝华  屈奋雄  张鹏程  刘如琦  徐英新  皮万有  张世民 《地质找矿论丛》1994,9(3):39-47

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Thaumasite from the Tschwinning mine,South Africa     

O. Grubessi  A. Mottana  E. Paris 《Mineralogy and Petrology》1986,35(3):149-156

Summary Thaumasite from the manganese mine of Tschwinning, South Africa, has the formula Ca_3.097 Si_1.062OH_6.372(CO₃)_0.994(SO₄)_1.000·11.596 H₂O. Unit cell parameters (a=11.013(2) Å,c=10.379(5) Å,V=1090.1(6) ų) and refraction indices (n_e=1.458(2),n _o=1.498(2)) compare well with the best ones available in the literature. The IR spectrum and DT-TG profiles are given. Contradictions between the IR spectrum, a recent structural refinement and the DT-TG are discussed, but cannot be explained satisfactorily.

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Thaumasit aus der Mangan-Mine von Tschwinning, Süd-Afrika

Zusammenfassung Thaumasit aus der Mangan-Mine von Tschwinning, Süd-Afrika, besitzt die Formel Ca_3.097 Si_1.062OH_6.372(CO₃)_0.994(SO₄)_1.000·11.596 H₂O. Die Parameter der Elementarzelle (a=11.013(2) Å,c=10.379(5) Å,V=1090.1(6) ų) und die Brechungsindizes (n _e=1.458(2),n _o=1.498(2)) zeigen gute Übereinstimmung mit verfügbaren Literaturdaten. Es werden ein IR-Spektrum und DT-TG-Profile präsentiert. Gegensätze zwischen dem IR-Spektrum, einer neueren Strukturverfeinerung und dem DT-TG werden diskutiert, können jedoch nicht zufriedenstellend erklärt werden.

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With 2 Figures  相似文献   

Neotectonics of the Pontides: implications for ‘incompatible’ structures along the North Anatolian fault     

A.M Celál Şengör  Si̇lva Büyükaşikoğlu  Nezi̇hi̇ Canitez 《Journal of Structural Geology》1983,5(2):211-216

Data for the post-Serravallian, ‘neotectonic’ evolution of the Pontides in northern Turkey indicate predominant ENE-WSW shortening with complementary NNW-SSE extension. We present a new fault plane solution for the Bartin earthquake (3 September 1968) and compare its mechanism with the movement picture of other neotectonic faults in the Pontides and northern Greece together with that of the Thessaloniki earthquake (20 May 1978). The general strain pattern exhibited by these structures agrees remarkably well with that inferred from early Tortonian-early Pleistocene structures reported from within the North Anatolian fault zone, which have been interpreted as indicating a possible reversal of the sense of movement along the North Anatolian transform fault. Here, we argue that such ‘incompatible’ structures may be related to the overall E-W shortening of Anatolia and the southern parts of the Black Sea resulting from the sideways continental escape from around the African and the Arabian promontories, rather than to hypothetical reversal of motion along the North Anatolian fault, for which there is no evidence other than the above-mentioned ‘incompatible’ structures. This new model also has important implications for seismicity and earthquake risk in regions contained within the southern part of the Black Sea plate.  相似文献   

Exfoliation of kaolinite by urea-intercalation precursor and microwave irradiation assistance process     

Pi Zhenbang  Liu Zhuoqin  Yang Chao  Tian Xike  Fei Jinbo  Zheng Jianhua 《Frontiers of Earth Science》2007,1(1):26-29

A type of exfoliated kaolinite was produced by urea-intercalation and original microwave irradiation assisted method. The product was investigated by Fourier transformation infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), scanning electronic microscopy (SEM), Brunauer-Emmett-Teller (BET) and laser particle analysis techniques. FT-IR spectra show that NHCO molecule exists in the intercalated kaolinite. XRD analyses indicate that the kaolinite sheet-like structure was disordered after microwave irradiation. The urea decomposition process and explosion effect between the sheet-like structures of kaolinite under microwave irradiation were discussed. The SEM and BET analyses reveal that the end product is exfoliated kaolinite with thin particles and increased surface area. Size and zeta potential analyses show that the particle size distribution is between 250 nm and 550 nm with normal distribution and the particle is negatively charged. In comparison with the conventional grind method, the process adopted appears to be economic and the exfoliated kaolinite end product may display a significantly enhanced performance in industrial applications.  相似文献   

Sea level pressure patterns associated with dry or wet monthly rainfall conditions in Turkey     

H. Kutiel  T. R. Hirsch-Eshkol  M. Türkeş 《Theoretical and Applied Climatology》2001,69(1-2):39-67

Summary  Monthly rainfall totals at 7 stations across Turkey and sea level pressure (SLP) in 16 grid points in the region delimited by the 20° E and 50° E longitudes and by the 30° N and 45° N latitudes were analysed. Data were available for a period longer than sixty years. The standard deviations of SLP at each grid point for each month, were calculated and mapped. For each station, months were defined as dry or wet according to their z scores: ≤ −1.0 or ≥ 1.0 respectively. Maps showing the SLP z scores of the corresponding dry or wet months for each station were prepared. The maps, enable to distinguish between SLP patterns associated with dry or wet conditions. Furthermore, correlations between monthly rainfall in each of the stations and SLP at each grid point were performed. The correlation coefficients were mapped. (a) The variability of the SLP decreases from the Balkans towards the Arabian Peninsula and is much larger in winter as compared with summer. (b) Relationship between rainfall in Turkey and the regional SLP is large in winter and non existing in summer. (c) Pressure patterns associated with dry conditions, show usually positive SLP departures, whereas, pressure patterns associated with wet conditions show usually negative SLP departures. (d) There is a great resemblance between pressure patterns associated with wet conditions and correlation maps of the same months. Received September 4, 2000 Revised January 15, 2001  相似文献   

洞庭湖区第四纪气候变化的初步探讨   总被引：14，自引：0，他引：14  

张人权  梁杏  张国梁  皮建高 《地质科技情报》2001,20(2):1-5

探讨了洞庭湖区第四纪以来的气候变化，初步得出以下规律：更新世气候变化剧烈，气候组合暖湿（温湿）与冷干；全新世气候转为温凉，主要气候组合为温湿与凉干；历史时期气候主要仍温湿与凉干交替，但15 世纪以来出现短暂的温干与凉温期；15世纪以来，气候波动频繁，有愈来愈不稳定的趋向，进入20世纪，旱涝灾害更加。在全球变暖的背景下，预计该区未来气候趋向于暖湿，但不排除暖干的可能性。  相似文献   

Ophiolite emplacement by strike-slip tectonics between the Pontide Zone and the Sakarya Zone in northwestern Anatolia, Turkey     

Ali Elmas  Erdinç Yiğitbaş 《International Journal of Earth Sciences》2001,90(2):257-269

Northwestern Anatolia contains three main tectonic units: (a) the Pontide Zone in the north which consists mainly of the Gstanbul-Zonguldak Unit in the west and the BallLda<-Küre Unit in the east; (b) the Sakarya Zone (or Continent) in the south, which is juxtaposed against the Pontide Zone due to the closure of Paleo-Tethys prior to Late Jurassic time; and (c) the Armutlu-OvacLk Zone which appears to represent a tectonic mixture of both zones. These three major tectonic zones are presently bounded by the two branches of the North Anatolian Transform Fault. The two tectonic contacts follow older tectonic lineaments (the Western Pontide Fault) which formed during the development of the Armutlu-OvacLk Zone. Since the earliest Cretaceous, an overall extensional regime dominated the region. A transpressional tectonic regime of Coniacian/Santonian to Campanian age caused the welding of the Gstanbul-Zonguldak Unit to the Sakarya Zone by an oblique collision. In the Late Campanian, a transtensional tectonic regime developed, forming a new basin within the amalgamated tectonic mosaic. The different tectonic regimes in the region were caused by activity of the Western Pontide Fault. Most of the ophiolites within the Armutlu-OvacLk Zone belong to the Paleo-Tethyan and/or pre-Ordovician ophiolitic core of the Gstanbul-Zonguldak Unit. The Late Cretaceous ophiolites in the eastern parts of the Armutlu-OvacLk Zone were transported from Neo-Tethyan ophiolites farther east by left-lateral strike-slip faults along the Western Pontide Fault. There is insufficient evidence to indicate the presence of an ocean (Intra-Pontide Ocean) between the Gstanbul-Zonguldak Unit and the Sakarya Zone during Late Cretaceous time.  相似文献