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971.
This paper investigates the impact of active tectonics on the geomorphic processes and landscape evolution along the Kazerun Fault Zone (KFZ) in the Zagros Mountains of Iran using spatial analysis of geomorphic indices. We document how topography and morphology are influenced by active tectonic deformation. The Zagros fold–thrust belt is an area of active crustal shortening where northwest–southeast oriented fault‐related folds become younger from north to south and from southeast to northwest. This temporal and spatial evolution of the belt was tested using geomorphic indices of active tectonics that include mountain front sinuosity index (Smf), the valley width/height ratio (Vf), drainage basin asymmetry factor, hypsometric integral, drainage basin shape ratio and mean axial slope of the channel. Change in the geomorphic indices is the result of active fold growth and change in the uplift rate. Decreasing Smf and Vf values from north (Smf = 2.01; Vf = 0.5) to south (Smf = 1.12; Vf = 0.2) and from southeast (Smf = 1.84; Vf = 0.8) to northwest (Smf = 1.54; Vf = 0.1) points to a migration of the active crustal shortening towards W–SW. The combined geomorphic (field evidences) and morphometric data (quantitative analysis of geomorphic indices) provide evidence of relative variation in the tectonic activity along the Kazerun Fault Zone and related landforms. The utilization of geomorphic parameters with comparison to the field observations exhibits change in relative tectonic activities mostly corresponding to the change in mechanism of the prominent fault zones in the study area. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
972.
Syed Salman Ali Wahab Uddin Ramesh Chandra D. L. Mary Bojan Vršnak 《Solar physics》2007,240(1):89-105
The eruption of limb prominence on 21 April 2001 associated with two coronal mass ejections (CMEs) is investigated. Hα images reveal two large-scale eruptions (a prominence body and a southern foot-point arch), both showing helical internal
structure. These two eruptions are found to be spatially and temporally associated with the corresponding CMEs. The kinematics
and the study of geometrical parameters of the prominence show that the eruption was quite impulsive (with peak acceleration
≈470 m s−2) and has taken place for relatively low pitch angle of helical threads, not exceeding tan θ≈1.2. The stability criteria of the prominence are revisited in the light of the model of Vršnak (1990, Solar Phys.
129, 295) and the analysis shows that the eruption violates the instability criteria of that model. Finally, the energy stored
in the prominence circuit and the energies (kinetic, potential, and magnetic) of the associated CMEs are estimated and it
is found that there was enough energy stored in the prominence to drive the two CMEs.
S.S. Ali is on leave from Aligarh Muslim University, Aligarh, 202 002, India. 相似文献
973.
974.
Syed Salman Ali Wahab Uddin Ramesh Chandra 《Journal of Astrophysics and Astronomy》2006,27(2-3):347-352
Here we present a preliminary analysis of a helical eruptive prominence at the east limb of the Sun on 21 April 2001. Unusually
this eruption is associated with a double CME. We have tried to study the morphology of the event, energy budget of the prominence
and associated CMEs. Our analysis shows that the prominence and first CME started simultaneously from the limb and prominence
carries sufficient energy to feed both the CMEs. Moreover, it is also concluded that CMEs are magnetically driven and internally
powered. 相似文献
975.
Ramadan M. Ali 《Astrophysics and Space Science》2007,310(3-4):201-204
Cylindrically symmetric perfect fluid solutions are derived for the Levi-Civita metric. The pressure P is finite. The matter density is greater than the stresses in the material. The solutions are inside cylinders of bounded
radius at which the pressure vanishes. The range of σ, for which the sources have been matched to the Levi-Civeta metric is ∞>σ>0. The solutions are regular and satisfy energy conditions 相似文献
976.
A feeding trial was conducted for 75 d to evaluate the nutritive value of a mixture of animal by-products(MAB) as a possible protein source in diets for juvenile mangrove red snapper,Lutjanus argentimaculatus(mean initial body weight,30 g). Fish were fed one of five isonitrogenous diets(40% crude protein) replacing 0,25%(MAB25),50%(MAB50),75%(MAB75) and 100%(MAB100) of fish meal protein with similar percentages of MAB. The MAB consisted of 25% cow liver meal,20% leather meal,20% meat and bone meal,15% blood meal,10% APC(poultry feather meal),8% poultry manure dried,1.5% choline and 0.5% chromic oxide. After 75 d of feeding,fish fed with diets MAB50,MAB75 and MAB100 exhibited significantly lower growth per-formance than that of fish fed with control and MAB25 diets. The optimum level of MAB was estimated to be 23%. Replacement of fish meal by MAB23% showed the following performance:maximum weight gain,510%;SGR,2.39% and FCE,2.83%. The MAB substitution up to 75% of fish meal protein in diets did not show differences in apparent protein digestibility(83.6% for MAB25,79.2% for MAB50,78.7% for MAB75) compared with control(83.4%),whereas in MAB100 group digestibility(65.3%) was sig-nificantly lower than in other groups. The apparent phosphorus absorption of test diet groups was significantly higher(37.1% for MAB25,28.5% for MAB50,55.6% for MAB75 and 54.5% for MAB100) than that of control(11.2%). The levels of protein and ash in the whole body,carcass and viscera increased as MAB substitution in diets increased,whereas lipids and moisture remained con-sistent among all treatment groups. These results showed that approximately 23% of fish meal protein could be replaced by a mixture of animal by-products for juvenile snapper growing from 30 g to 167 g in 75 d without compromising growth performance and feed efficiency. 相似文献
977.
Ali Ismet Kanlı 《Journal of Applied Geophysics》2009,67(1):52-62
The impact of initial velocity models on final image reconstruction results and how to construct a proper initial velocity model in near-surface tomography studies are investigated on a two-layer synthetic model with gradually increasing velocity with depth. Refraction initial velocity models and linear velocity function models are tested on both synthetic and field data to obtain images close to reality. It is concluded that velocity function type initial models should be preferred in soft alluvial deposits that exist within the investigated depths, whereas refraction initial models should be preferred in the groundwater table or with strong refractors' existence within the investigated depths to obtain optimum subsurface images in refraction–diving wave seismic tomography. 相似文献
978.
Recently we (Roy and Rana, 1990a) critically examined the self-consistency of the EIH equations of motion. A static spherically symmetric body as was pointed out there may not appear as a point mass with all its mass concentrated at its centre to a particle placed outside the body. An attempt to analyse this aspect further is made here in the context of the Chandrasekhar gauge. A comparison is also made with the general solutions obtained by Schwarzschild in the standard co-ordinates. Certain difficulties still exist. 相似文献
979.
The effect of Hall currents have been studied on the instability of a stratified layer of a self-gravitating finitely conducting plasma of varying density. It is assumed that the plasma is permeated by a variable horizontal magnetic field stratified vertically. The stability analysis has been carried out for longitudinal mode of wave propagation. The solution has been obtained through integral equation approach. The dispersion relation has been derived and solved numerically. It is found that both the Hall currents and finite conductivity have a destabilizing influence on the growth rate of the unstable mode of disturbance. 相似文献
980.
Daryoushi Masoud Saffari Hamid Mahdavian Abbas 《Izvestiya Physics of the Solid Earth》2021,57(6):950-964
Izvestiya, Physics of the Solid Earth - ln this study, two relationships have been presented for predicting the significant duration values $$({{D}_{{s5 - 75}}}$$ and $${{D}_{{s5 - 95}}})~$$ of... 相似文献