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21.
The Chauki, Mandi, Manil colony, Changpur, Khawas and Naghal areas are situated in between the limbs of Hazara Kashmir Syntaxis (HKS). HKS is the part of Himalayan fold and thrust belt that lies in sub-Himalayan domain. Seismically, this is an active zone. Early Miocene to Recent sedimentary rocks are exposed in the area. The stratigraphic units in Kashmir basin are the cover sequence of the Indian plate. These non-marine lithostratigraphic units are molasse deposits formed by the deposition of sediments coming from north carried by the rivers originated from higher Himalayas. Murree Formation of early Miocene age is the oldest rock unit in the studied area. Siwalik Group; Chinji, Nagri, Dhok Pathan and Soan formations of early Miocene to Pliocene and Mirpur Formation of Pleistocene age is exposed. The area is structurally deformed into folds and faults. The Sarda Sarhota syncline, Mandi syncline and Fagosh anticline are major folds in the area. These folds are isoclinal to open in nature, southwest or northeast verging and thrust direction is southwest or northeast. Major reverse faults are Riasi fault and Fagosh fault. The Changpur fault is a normal fault. Primary sedimentary structures present in the area are load cast, ripups and cross bedding. The facing of beds have been marked on the basis of these sedimentary structures. 相似文献
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Seismic hazard assessment for Quetta is carried out using probabilistic seismic hazard analysis technique based on area sources and augmented by line source used for the first time in Pakistan. Seismic data has been collected and analyzed in spatial and temporal domains. Five Seismic Zones have been modeled in line with tectonics of the region with b-value of 1.14 using regression. The b-value is slightly higher, which is attributed to the fact that aftershocks were not removed as it distorted the dataset. Five fault sources are modeled, with three as reverse and two as strike-slip with 7.8 as maximum magnitude. Mach Structure is included in the tectonics for the first time. The attenuation relation used in the present study is recommended by various researchers. The expected Peak Ground Acceleration for 500-year return period is 4.79 m/s2 for rock outcrop and characterized as very high. Furthermore, variation in spectral acceleration within Quetta city is observed, for which spectral curves are developed for four different places. 相似文献
23.
Ehtisham Abdul Rehman 《Arabian Journal of Geosciences》2017,10(4):88
Reduced amplitude and distorted dispersion of seismic waves caused by attenuation, especially strong attenuation, always degrade the resolution of migrated images. To improve seismic imaging, attenuation must be compensated. This study addresses the factors causing seismic attenuation in Jati Block. Jati Block lies in Lower Indus Basin, Pakistan, approximately 25 mi north of the offshore Indus. Method used for Q factor is empirical equation method. Q factor correlation indicates that there are three major zones of attenuation in Jati block, i.e., zone I (surface to top Khadro), zone II (Upper Goru Formation), and zone III (Lower Goru Formation). Lowest Q value is in zone I, followed by zone II and zone III, respectively. Commonly, Khadro Formation (Basalt) of Paleocene and saucer-shaped igneous intrusion is considered as sources of attenuation. However, surprisingly, Khadro Formation of Paleocene and saucer-shaped igneous intrusion is zone of minimum attenuation and causes minimal transmission loss. Anisotropy analysis is performed to determine cause of attenuation within these zones. Thomson anisotropic parameters are computed for vertical wells using Backus averaging algorithm. These parameters are calibrated using sonic scanner data available for one well. Correlation of Q factor curve with mud log suggests that loose, unconsolidated sands and sand-shale layering are sources of attenuation within zone I. Attenuation in this zone is mostly due to fluid motion relative to the framework of loosely packed grains. Major lithology of Upper Goru Formation is marl. It is a slow formation, and in this formation, P wave loses energy to the formation in what is known as leaky P mode (sonic logging) and is dispersive (seismic). Epsilon (?) value is greater than almost 0.02 throughout Lower Goru Formations, indicating that this formation is strongly anisotropic. Fluctuation of epsilon (?) in Lower Goru Formation also suggests that this formation is causing layer-induced anisotropy. This layer-induced anisotropy in Lower Goru Formation added by dispersive and slow nature of Upper Goru Formation causes rapid attenuation. 相似文献
24.
Qinmin Zheng S Rehman Md Mahbub Alam L M Alhems A Lashin 《Journal of Earth System Science》2017,126(3):36
Understanding the inherent features of wind speed (variability on different time scales) has become critical for assured wind power availability, grid stability, and effective power management. The study utilizes the wavelet, autocorrelation, and FFT (fast Fourier transform) techniques to analyze and assimilate the fluctuating nature of wind speed data collected over a period of 29–42 years at different locations in the Kingdom of Saudi Arabia. The analyses extracted the intrinsic features of wind speed, including the long-term mean wind speed and fluctuations at different time scales (periods), which is critical for meteorological purposes including wind power resource assessment and weather forecasting. The long-term mean wind speed varied between 1.45 m/s at Mecca station and 3.73 m/s at Taif. The annual variation is the largest (±0.97 m/s) at Taif and the smallest (±0.25 m/s) at Mecca. Similarly, the wind speed fluctuation with different periods was also discussed in detail. The spectral characteristics obtained using FFT reveal that Al-Baha, Najran, Taif and Wadi-Al-Dawasser having a sharp peak at a frequency f = 0.00269 (1/day) retain a more regular annual repetition of wind speed than Bisha, Khamis-Mushait, Madinah, Mecca, and Sharourah. Based on the autocorrelation analysis and FFT results, the stations are divided into three groups: (i) having strong annual modulations (Al-Baha, Najran, Taif and Wadi-Al-Dawasser), (ii) having comparable annual and half-yearly modulations (Bisha, Khamis-Mushait, and Mecca) and (iii) having annual modulation moderately prominent (Madinah and Sharourah). 相似文献
25.
Tahseenullah Khan Mamoru Murata M. Qasim Jan Hafiz Ur Rehman Muhammad Zafar Hiroaki Ozawa Anwar Qadir Saqib Mehmood 《Arabian Journal of Geosciences》2017,10(14):308
The Nagar Parkar Igneous Complex consists of Neoproterozoic igneous and metamorphic rocks dissected by mafic, felsic, and rhyolitic dykes. The latter can be classified broadly into porphyritic felsic dykes intruding gray and pink granites at Nagar Parkar and the surrounding areas, and the orthophyric felsic dykes intruding amphibolites, deformed pink granites, and the alkaline mafic dykes in the Dhedvero area, north of Nagar Parkar. The porphyritic felsic dykes are composed of perthites, quartz, and albitic plagioclase whereas the orthopheric felsic dykes contain K-feldspar (dominant), plagioclase, and minor quartz. Geochemically, the porphyritic and orthophyric felsic dykes are subalkaline and alkaline demonstrating post-orogenic A2- and OIB-A1-type characteristic on Nb–Y–Ce and Nb–Y–3Ga ternary plots, respectively. One orthophyric felsic dyke contains normative acmite and sodium metasilicate. This study suggests two distinct tectonic regimes for the origin of the felsic dykes of the area. The porphyritic felsic dykes show similarities with the ~800–700 Ma granites of the area, the rhyolite dykes of the Mount Abu, western Rajasthan in India, and the granites of the Seychelles microcontinent. The orthophyric felsic dykes show chemical resemblance with the Tavidar volcanic suite of western Rajasthan and the Silhouette and North islands of the Seychelles microcontinent. This study confirms spatial and temporal links among the Rodinian fragments exposed in the Nagar Parkar area of Pakistan, western Rajasthan of India, and the Seychelles microcontinent. 相似文献
26.
Hiroshi Yamamoto Natsumi Nakamori Masaru Terabayashi Hafiz Ur Rehman Masahiro Ishikawa Yoshiyuki Kaneko Takashi Matsui 《Island Arc》2010,19(3):458-469
Geological observations in the Horoman area, south‐central Hokkaido, show that the Horoman peridotite complex of the Hidaka metamorphic belt is a tectonic slice about 1200 m thick. The peridotite slab is intercalated into a gently east‐dipping structure. The underlying unit is a Cretaceous–Paleogene accretionary complex. Riedel shear planes in the sedimentary layers of the accretionary complex near the structural bottom of the peridotite slab indicate top‐to‐the‐west (thrust) displacement. The overlying unit is composed of felsic–pelitic gneisses and mafic–felsic intrusive rocks (the Hidaka metamorphic rocks). The boundary surface between the peridotite complex and metamorphic rocks forms a domal structure. Microstructures of sheared metamorphic rocks near the structural top of the peridotite slab indicate top‐to‐the‐east (normal) displacement. The results combined with previous studies suggest that the Horoman peridotite complex was emplaced onto the Asian margin (Northeast Japan) during the collision between the Asian margin and the Hidaka crustal block. 相似文献
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Ijaz Ahmad Ahmad Zulfiqar Lisa Mona Mahmood Syed Amer Ali Asad Rehman Obaid Ur 《Water Resources》2019,46(6):894-909
Water Resources - Snow cover dynamics play an important role in the hydrological characteristics of Upper Indus Basin (UIB) of Pakistan in terms of seasonal accumulation and depletions. The current... 相似文献
29.
Hafiz U. Rehman Tahseenullah Khan Hao‐Yang Lee Sun‐Lin Chung Mamoru Murata M. Qasim Jan 《Island Arc》2019,28(6)
We report Permian (ca. 272 Ma ±5.4 Ma) felsic dykes that intrude into the Neoproterozoic (ca. 750 Ma) magmatic suite of the Nagar Parkar Igneous Complex (NPIC), the western extension of the Malani Igneous Suite (MIS). The NPIC consists of Neoproterozoic basement amphibolites and granites (riebeckite–aegirine gray granites and the biotite–hornblende pink granites), all of which are intruded by several generations of mafic and felsic dykes. Granitic magmatism occurred in the Late Neoproterozoic (ca. 750 Ma) due to the subduction‐, followed by the rift‐related tectonic regime during the breakup of the Rodinia supercontinent. U–Th–Pb zircon and monazite CHIME age data of 700–800 Ma from the earlier generation porphyritic felsic dykes suggest the dyke intrusion was coeval or soon after the emplacement of the host granites. Our findings of Permian age orthophyric felsic dykes provide new insights for the prevalence of active tectonics in the MIS during late Paleozoic. Textural features and geochemistry also make the orthophyric dykes distinct from the early‐formed porphyritic dykes and the host granites. Our newly obtained age data combined with geochemistry, suggest the existence of magmatism along the western margin of India (peri‐Gondwana margin) during Permian. Like elsewhere in the region, the Permian magmatism in the NPIC could be associated with the rifting of the Cimmerian micro‐continents from the Gondwana. 相似文献
30.
Ziaur Rehman Ansari L. A. K. Rao Alia Yusuf 《Journal of the Geological Society of India》2012,79(5):505-514
Remote Sensing and GIS techniques have been proved to be efficient tools in the delineation, updating and morphometric analysis of drainage basin. The present study incorporates a morphometric analysis of three sub-basins of Fatehabad area of Agra district using remote sensing and GIS techniques. The morphometric parameters of the sub-basins are classified under linear, areal and relief aspects. The drainage pattern exhibited by the main river Yamuna and its tributaries shows a dendritic pattern indicating homogenously underlain material while the mean bifurcation ratio values suggest that the geological structures are not disturbing the drainage pattern. The form factor value of sub-basins suggests that the main basin is more or less elongated. Circularity ratio values of the three sub-basins fall within range of elongated basin and low discharge. The area has low density indicating that the region has high permeable sub-soil material and dense vegetation. The values of drainage texture, drainage density and infiltration number indicate that sub-basin-III has the highest infiltration rate and low runoff, hence contributing most to the underground water resources. This study also indicates porous and permeable sub-soil condition in sub-basin-III. The values of sub-basin-I indicate low permeable subsoil material owning to high infiltration number value, hence low infiltration and high runoff. 相似文献