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1.
Narges Afsari Forogh Sodoudi Fataneh Taghizadeh Farahmand Mohammad Reza Ghassemi 《Journal of Seismology》2011,15(2):341-353
Receiver functions are widely employed to detect P-to-S converted waves and are especially useful to image seismic discontinuities
in the crust. In this study we used the P receiver function technique to investigate the velocity structure of the crust beneath
the Northwest Zagros and Central Iran and map out the lateral variation of the Moho boundary within this area. Our dataset
includes teleseismic data (M
b ≥ 5.5, epicentral distance from 30° to 95°) recorded at 12 three-component short-period stations of Kermanshah, Isfahan and
Yazd telemetry seismic networks. Our results obtained from P receiver functions indicate clear Ps conversions at the Moho
boundary. The Moho depths were firstly estimated from the delay time of the Moho converted phase relative to the direct P
wave beneath each network. Then, we used the P receiver function inversion to find the properties of the Moho discontinuity
such as depth and velocity contrast. Our results obtained from PRF are in good agreement with those obtained from the P receiver
function modeling. We found an average Moho depth of about 42 km beneath the Northwest Zagros increasing toward the Sanandaj-Sirjan
Metamorphic Zone and reaches 51 km, where two crusts (Zagros and Central Iran) are assumed to be superposed. The Moho depth
decreases toward the Urmieh-Dokhtar Cenozoic volcanic belt and reaches 43 km beneath this area. We found a relatively flat
Moho beneath the Central Iran where, the average crustal thickness is about 42 km. Our P receiver function modeling revealed
a shear wave velocity of 3.6 km/s in the crust of Northwest Zagros and Central Iran increasing to 4.5 km/s beneath the Moho
boundary. The average shear wave velocity in the crust of UDMA as SSZ is 3.6 km/s, which reaches to 4.0 km/s while in SSZ
increases to 4.3 km/s beneath the Moho. 相似文献
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3.
Fataneh Taghizadeh-Farahmand Forough Sodoudi Narges Afsari Mohammad R. Ghassemi 《Journal of Seismology》2010,14(4):823-836
We computed P and S receiver functions to investigate the lithospheric structure beneath the northwest Iran and compute the Vp/Vs ratio within the crust of this seismologically active area. Our results enabled us to map the lateral variations of the Moho as well as those of the lithosphere–asthenosphere boundary (LAB) beneath this region. We selected data from teleseismic events (Mb?>?5.5, epicentral distance between 30° and 95° for P receiver functions and Mb?>?5.7, epicentral distance between 60° and 85° for S receiver functions) recorded from 1995 to 2008 at 8 three-component short-period stations of Tabriz Telemetry Seismic Network. Our results obtained from P receiver functions indicate clear conversions at the Moho boundary. The Moho depth was firstly estimated from the delay time of the Moho converted phase relative to the direct P wave. Then we used the H-Vp/Vs stacking algorithm of Zhu and Kanamori to estimate the crustal thickness and Vp/Vs ratio underneath the stations with clear Moho multiples. We found an average Moho depth of 48 km, which varies between 38.5 and 53 km. The Moho boundary showed a significant deepening towards east and north. This may reveal a crustal thickening towards northeast possibly due to the collision between the Central Iran and South Caspian plates. The obtained average Vp/Vs ratio was estimated to be 1.76, which varies between 1.73 and 1.82. The crustal structure was also determined by modeling of P receiver functions. We obtained a three-layered model for the crust beneath this area. The thickness of the layers is estimated to be 6–11, 18–35, and 38–53 km, respectively. The average of the shear wave velocity was calculated to be 3.4 km/s in the crust and reaches 4.3 km/s below the Moho discontinuity. The crustal thickness values obtained from P receiver functions are in good agreement with those derived by S receiver functions. In addition, clear conversions with negative polarity were observed at ~8.7 s in S receiver functions, which could be related to the conversion at the LAB. This may show a relatively thin continental lithosphere of about 85 km implying that the lithosphere was influenced by various geodynamical reworking processes in the past. 相似文献
4.
The recently released Planck data have constrained 4-dimensional inflationary parameters even more accurately than ever. We consider an extension of the braneworld model with induced gravity and a non-minimally coupled scalar field on the brane. We constraint the inflation parameters in this setup, by adopting six types of potential, in confrontation with the joint Planck + WMAP9 + BAO data. We show that a potential of the type V(φ)=V 0exp(?βφ) has the best fit with newly released observational data. 相似文献
5.
Arghavan Hosseinpouri Mehdi Mohammadi Elham Ehsandoost Paria Sharafi-Badr Narges Obeidi 《海洋学报(英文版)》2022,41(12):133-141
Marine macroalgal sulfated fucose-containing polysaccharides, like fucoidan, have drawn significant attention due to their biotechnological potentials, such as anti-cancer, antioxidant, and anti-cholinesterase activities. The fucoidan derived from brown macroalgae Sargassum angustifolium species (FSA) was investigated for its cytotoxic effects and alterations in cell proliferation, and cell cycle-related gene expression in the present study occurred on NB4 cell line. The results showed that FSA would induce p53, p21, pro-apoptotic genes and increase expression of the p15 gene as a cell arrest marker. Also, FSA inhibited the anti-apoptotic effect of the Bcl-2 gene and decreased dnmt-1 gene expression. FSA significantly exhibited potent 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (p<0.05) with an IC50 value of 0.157 mg/mL and showed moderate anti-acetylcholinesterase activity with an IC50 value of 1.20 μg/mL. These results indicated the potential of FSA for the development of therapeutic or preventive agents of cancer and Alzheimer’s disease mainly through cytotoxic effect and AChE (acetylcholinesterase) inhibition as well as additional antioxidant capacities. 相似文献
6.
We consider cosmological dynamics of a canonical bulk scalar field, which is coupled non-minimally to 5-dimensional Ricci scalar in a DGP setup. We show that presence of this non-minimally coupled bulk scalar field affects the jump conditions of the original DGP model significantly. Within a superpotential approach, we perform some numerical analysis of the model parameter space and consider bulk-brane energy exchange in this setup. Also we show that the normal, ghost-free branch of the DGP solutions in this case has the potential to realize a self-consistent phantom-like behavior and therefore explains late time acceleration of the universe in a consistent way. 相似文献
7.
Fataneh Taghizadeh-Farahmand Forough Sodoudi Narges Afsari Mohammad R. Ghassemi 《Journal of Seismology》2010,14(4):839-836
We computed P and S receiver functions to investigate the lithospheric structure beneath the northwest Iran and compute the
Vp/Vs ratio within the crust of this seismologically active area. Our results enabled us to map the lateral variations of
the Moho as well as those of the lithosphere–asthenosphere boundary (LAB) beneath this region. We selected data from teleseismic
events (Mb > 5.5, epicentral distance between 30° and 95° for P receiver functions and Mb > 5.7, epicentral distance between 60° and 85° for S receiver functions) recorded from 1995 to 2008 at 8 three-component
short-period stations of Tabriz Telemetry Seismic Network. Our results obtained from P receiver functions indicate clear conversions
at the Moho boundary. The Moho depth was firstly estimated from the delay time of the Moho converted phase relative to the
direct P wave. Then we used the H-Vp/Vs stacking algorithm of Zhu and Kanamori to estimate the crustal thickness and Vp/Vs
ratio underneath the stations with clear Moho multiples. We found an average Moho depth of 48 km, which varies between 38.5
and 53 km. The Moho boundary showed a significant deepening towards east and north. This may reveal a crustal thickening towards
northeast possibly due to the collision between the Central Iran and South Caspian plates. The obtained average Vp/Vs ratio
was estimated to be 1.76, which varies between 1.73 and 1.82. The crustal structure was also determined by modeling of P receiver
functions. We obtained a three-layered model for the crust beneath this area. The thickness of the layers is estimated to
be 6–11, 18–35, and 38–53 km, respectively. The average of the shear wave velocity was calculated to be 3.4 km/s in the crust
and reaches 4.3 km/s below the Moho discontinuity. The crustal thickness values obtained from P receiver functions are in
good agreement with those derived by S receiver functions. In addition, clear conversions with negative polarity were observed
at ~8.7 s in S receiver functions, which could be related to the conversion at the LAB. This may show a relatively thin continental
lithosphere of about 85 km implying that the lithosphere was influenced by various geodynamical reworking processes in the
past. 相似文献
8.
Narges?PalizdanEmail author Yashar?Falamarzi Yuk?Feng?Huang Teang?Shui?Lee 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(4):853-877
The main purpose of this study was to determine the most dominant periodic components that affect the annual and seasonal precipitation trends in each homogenous rainfall region in the Langat River Basin, Malaysia for the period 1982–2011. Performing this research could be essential because in the previous studies on detection of trend in Malaysia, the details of variations of different time scales and the periodic responsible for the observed trends were not investigated. Using discrete wavelet transform (DWT) coupled with Mann–Kendall at the regional scale for the first time particularly in the context of Malaysia is the contribution of this study. In order to form the homogenous rainfall regions, first the total annual and seasonal precipitation in each year was spatialized into 5 km × 5 km grids using the inverse distance weighting method. The obtained precipitation series for the grids were then grouped applying the Ward’s clustering method based on the similarity of precipitation time series. After allocating a cluster number to each grid, the boundary of the regions was formed in ArcGIS software. Following which, in each homogenous region the areal precipitation series were computed by the Thiessen polygon method. The Mann–Kendall (MK) test was used to detect trend and the DWT coupled with the MK test and the sequential MK analysis were then utilized in order to find out the time scale which affected the observed trend in each homogenous region. On annual scale, it was found that D1 (plus approximation) component in regions Annual Cluster1 (AC1) and AC2 was the periodic mode responsible for trends. On seasonal scale, in regions Northeast monsoon Cluster 1 (NC1), NC3, SC1 and Southwest monsoon Cluster 2 (SC2), D1 (with approximation), in regions NC4, Inter monsoon 1 Cluster 1 (I1C1), I1C2, Inter monsoon 2 Cluster 1 I2C1 and I2C2, Detail 2 (D2) (plus approximation) and in region NC2, Detail 3 (D3) (with approximation added) component were the most influential periodicity for trends. 相似文献
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10.
Monjezi Sara Najarchi Mohsen Mo’meni Mansour Monjezi Narges Hassuninezade Houshang 《Water Resources》2021,48(6):1013-1022
Water Resources - To water quality management of the Gotvand Reservoir, this paper attempts to determine to what extent the negative impacts of Anbar salt domes dissolution can be reduced... 相似文献