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41.
为探讨玉树地震是否为超剪切破裂事件,利用Yagi的方法重新进行了此次地震震源破裂过程的反演。通过给定不同的破裂速度进行对比,发现当破裂速度为4.7km/s时,理论与实际观测结果拟合残差最小,且反演结果更符合实际。另据P波高频辐射能量包络反演,破裂传播速度在4.7~5.8km/s范围内,而该地区的剪切波速度则为3.0~3.6km/s,从而证明了此次地震超剪切破裂现象的存在。反演结果表明,此次地震在玉树段的NW和SE段形成了19和31km的地表破裂,而震中所在的中段由于隆宝湖拉分盆地的存在,造成了15km的未破裂区。超剪切破裂是造成SE段玉树县城遭受严重破坏的原因之一。 相似文献
42.
Using measured radial velocity data of nine double lined spectroscopic binary systems NSV 223, AB And, V2082 Cyg, HS Her, V918 Her, BV Dra, BW Dra, V2357 Oph, and YZ Cas, we find corresponding orbital and spectroscopic elements via the method introduced by Karami and Mohebi (Chin. J. Astron. Astrophys. 7:558, 2007a) and Karami and Teimoorinia (Astrophys. Space Sci. 311:435, 2007). Our numerical results are in good agreement with those obtained by others using more traditional methods. 相似文献
43.
Water Resources - There are two significant reasons for the uncertainties of water demand. On one hand, an evolving technological world is plagued with accelerated change in lifestyles and... 相似文献
44.
Acta Geotechnica - A vast majority of experimental researches focuses on the cutting action of a sharp cutter, while there has been limited experimental work devoted to the study of the contact... 相似文献
45.
Ghasem Aghli Bahman Soleimani Sayed Salman Tabatabai Iman Zahmatkesh 《Arabian Journal of Geosciences》2017,10(12):265
Evaluation of fractures and their parameters, such as aperture and density, is necessary in the optimization of oil production and field development. The purpose of this study is the calculation of fracture parameters in the Asmari reservoir using two electrical image logs (FMI, EMI), and the determination of fracture parameters’ effect on the porosity and permeability using thin sections and velocity deviation log (VDL). The results indicate that production in the Asmari reservoir is a combination of fractures and rock matrix. Fracture aperture (VAH) and fracture porosity (VPA) are only measurable with core and image logs directly. However, regarding core limitations, the image log has been recognized as the best method for fracture parameter determination due to their high resolution (2.5 mm). In this study, VDL log and thin sections have been used as auxiliary methods which may be available in all wells. The VDL log provides a tool to obtain downhole information about the predominant pore type in carbonates. Results indicate that between fracture parameters, VAH is considered as the most important parameter for determining permeability. For well No. 3, VAH ranges from minimum 51 × 10?5 mm to maximum 0. 047 mm and VPA changes from min 10?5% to maximum 0.02056%. For well No. 6, VAH varies from 5 × 10?4 to 0.0695 mm and VPA varies from 10?5 to 0.015%. Therefore, due to high fracture density and fracture aperture, it seems that most of effective porosity originates from fractures especially in well No. 3. However, VDL for well No. 6 indicates that intercrystalline and vuggy porosity are the dominant porosity. This result may be an indication for fracture set diversity in the two studied wells. While in well No. 3, they related to the folding and active faults, in well No. 6 they are only of folding type. Furthermore, results indicate the high capability for both of EMI and FMI image logs for calculation of fracture and vug parameters in the carbonate reservoirs. 相似文献
46.
Seyed Morteza Mirabbasi Mohammad Javad Ameri Habiballah Zafarian-Rigaki Iman Rahimzadeh-Kivi 《Arabian Journal of Geosciences》2016,9(3):235
Shale formation swelling is one of the main factors affecting wellbore instability and associated problems in drilling operation. In order to eliminate these problems, it is important to investigate formation characteristics and understand mechanisms of rock-fluid interaction, from chemical/mechanical point of view. Shale membrane efficiency is known as an important parameter affecting wellbore instability. In order to measure this parameter, many mathematical models and experimental efforts have been carried out which consider mechanical-chemical processes for rock-fluid interactions. In this study, the field equations governing the problem have been derived based on the linear chemo-poroelastic theory and solved using analytical/numerical methods. Afterward, a comprehensive workflow to characterize the chemo-poroelastic parameters of illite-rich shale is conducted in the laboratory. In fact, mineralogical and apparent properties of shale sample have been described and some setups were performed such as triaxial test and membrane efficiency. Then genetic algorithm has been applied to solve an inverse problem and get a match between experimental data and modeling results. Ultimately, the three important properties in shale-fluid interactions, i.e., shale membrane efficiency, hydraulic, and chemical diffusivity coefficient have been estimated. Comparing the simulation results with the experimental data indicates that the simulation model can appropriately simulate the pore pressure transmission test. With this approach, the required parameters can be estimated with good accuracy without using time-consuming and costly tests. 相似文献
47.
We investigate the validity of the generalized second law of gravitational thermodynamics in a non-flat FRW universe containing
the interacting generalized Chaplygin gas with the baryonic matter. The boundary of the universe is assumed to be enclosed
by the dynamical apparent horizon. We show that for the interacting generalized Chaplygin gas as a unified candidate for dark
matter and dark energy, the equation of state parameter can cross the phantom divide. We also present that for the selected
model under thermal equilibrium with the Hawking radiation, the generalized second law is always satisfied throughout the
history of the universe for any spatial curvature, independently of the equation of state of the interacting generalized Chaplygin
gas model. 相似文献
48.
Iman?BabaeianEmail author Parviz?Rezazadeh 《Theoretical and Applied Climatology》2018,134(1-2):95-105
Indian monsoon is the most prominent of the world’s monsoon systems which primarily affects synoptic patterns of India and adjacent countries such as Iran in interaction with large-scale weather systems. In this article, the relationship between the withdrawal date of the Indian monsoon and the onset of fall precipitation in Iran has been studied. Data included annual time series of withdrawal dates of the Indian monsoon prepared by the Indian Institute for Tropical Meteorology, and time series of the first date of 25 mm accumulated precipitation over Iran’s synoptic weather stations in a 10-day period which is the basis for the cultivation date. Both time series were considered in Julian calendar with the starting date on August 1. The studied period is 1960–2014 which covers 55 years of data from 36 meteorological stations in Iran. By classifying the withdrawal dates of the Indian monsoon in three stages of late, normal, and early withdrawals, its relation with the onset of fall precipitation in western, southwestern, southern, eastern, central, and northern regions of Iran was studied. Results demonstrated that in four out of the six mentioned regions, the late withdrawal of the Indian monsoon postpones the onset of fall precipitation over Iran. No significant relation was found between the onset of fall precipitation in central region of Iran and the monsoon’s withdrawal date. In the western, southwestern, southern, and eastern regions of Iran, the late monsoon delays the onset of fall’s precipitation; while in the south Caspian Sea coastal area, it causes the early onset of autumnal precipitation. The lag in onset of fall precipitation in Iran which is coordinated with the late withdrawal of monsoon is accompanied with prolonged subtropical high settling over Iran’s plateau that prevents the southward movement of polar jet frontal systems. Such conditions enhance northerly wind currents over the Caspian Sea which, in turn, increase the precipitation in Caspian coastal provinces, which has a different behavior from the overall response of Iran’s climate to the late withdrawal of monsoon. In the phase of early monsoon withdrawal, the subtropical jet is located at the 200 hPa level in 32.5° north latitude; compared with the late withdrawal date, it shows a 2° southward movement. Additionally, the 500 hPa trough is also located in the Eastern Mediterranean, and the MSL pressure anomaly is between ? 4 to ? 7 hPa. The Mediterranean trough in the late withdrawal phase is located in its central zones. It seems that the lack of significant correlation between late withdrawal date of Indian monsoon and late fall’s precipitation onset in the central region of Iran depends on three reasons:1. Lack of adequate weather stations in central region of Iran.2. Precipitation standard deviations over arid and warm regions are high.3. Central flat region of Iran without any source of humidity is located to the lee side of Zagros mountain range. So intensification or development of frontal systems is almost prohibited over there. 相似文献