Simplified analysis method for multistorey base-isolated structures on viscoelastic halfspace     

Faruq M. A. Siddiqui  M. C. Constantinou 《地震工程与结构动力学》1989,18(1):63-77

A simplified procedure for the analysis of single-storey base-isolated structures on a viscoelastic halfspace is extended to multistorey structures. Results of displacements and base shear obtained by this procedure compare favourably to exact results obtained by a computer program that has been developed.  相似文献   

Visibility prediction based on artificial neural networks used in automatic network design     

Mohammad  Saadatseresht  Masood  Varshosaz 《The Photogrammetric Record》2007,22(120):336-355

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Rainfall-induced landslide in the active frontal fold–thrust belt of Northwestern Himalaya,Jammu: dynamics inferred by geological evidences and Ground Penetrating Radar     

Yudhbir Singh  Ahsan Ul Haq  G. M. Bhat  S. K. Pandita  Arjun Singh  Rameshwar Sangra  Gulzar Hussain  S. S. Kotwal 《Environmental Earth Sciences》2018,77(16):592

Landslides are the most established geological hazards in the frontal fold–thrust belt of Northwestern Himalaya comprising of Siwaliks and Murree strata. The continuous rainfall from 2 to 6 September, 2014 caused a massive landslide at village Sadal in Udhampur district of Jammu and Kashmir state. The landslide occurred in the early morning of September 6, 2014, destroying entire Sadal habitation comprising 45 houses, and killing 41 people and more than 500 domestic animals. Google earth images of pre and post-landslide events along with the field measurements show the kinematics of upper and lower parts of the slide. Horizontal and vertical components of displacement and mode of failure suggest the landslide as of complex nature. The shallow subsurface geophysical imaging through Ground Penetrating Radar (GPR) survey shows the failure plane composed of friable mudstone bed underlain by massive mudstone and overlain by cross-bedded sandstone. The depth of debris material above the failure plane ranges from 6 m at Site S1a-b to 10 m at Site-S2b and 20 m at Site S3a. The velocity analysis of Site-3 shows four thick layers represented from bottom to surface by L1—sandstone (V?=?0.16 m/ns, travel time?=?356.36 ns), L2—mudstone (V?=?0.17 m/ns, travel time?=?288.48 ns), L3—massive mudstone (V?=?0.19 m/ns, travel time 220.68 ns), and L4—cross-laminated sandstone (V?=?0.20 m/ns, travel time?=?77.58 ns) overlaying the failure plane. The study shows the landslide occur along the western limb of a fold identified during the present work. We mapped an old landslide on the same limb which shows 5–6 m-thick subsurface debris material with thick rock fragments involved in the landslide process. The detailed geological and geophysical investigations suggest that both the landslides were triggered by extreme rain fall events.  相似文献   

Development of a flood forecasting system using IFAS: a case study of scarcely gauged Jhelum and Chenab river basins     

Aamir Shahzad  Hamza Farooq Gabriel  Sajjad Haider  Ammara Mubeen  Muhammad Junaid Siddiqui 《Arabian Journal of Geosciences》2018,11(14):383

Development of a well-calibrated, distributed hydrological model for flood forecasting based on rainfall and snowmelt is quite challenging, especially when in situ data is limited or unavailable. This paper presents the study carried out to parameterise the Integrated Flood Analysis System (IFAS) model for the trans-boundary, scarcely gauged catchments of Jhelum and Chenab rivers in Pakistan. Rainfall-runoff analysis was performed with a two-layered tank configuration, integrating snowmelt and dam and barrage operation from the very upstream in India to Trimmu Barrage in Pakistan. A grid size of 5?×?5 km was considered. Global map topography, land cover and soil data was utilised. The model was tested considering different magnitudes of floods of the years 2014, 2015 and 2017. The results showed that the satellite rainfall product, i.e. Global Satellite Mapping of Precipitation (GSMaP-NRT), underestimated the rainfall volume, compared to the ground-gauged rainfall. The GSMaP-IF correction method showed poor performance owing to the lack of ground observatory rainfall data for correcting the trans-boundary part of the basin. The GSMaP-Type1 correction method showed good results, except for the confluence point where complex flow conditions were not properly reproduced by the model. In addition, the incorporation of dam and barrages in the model improved the simulated flow results. It is concluded that the satellite rainfall estimates must be corrected to improve the results. Snowmelt module estimated the snowmelt contribution as 3 to 7% and 4 to 23% of the average daily discharge during the monsoon season at Mangla Dam and Marala Barrage, respectively, during 2014 and 2015. This study assessed various correction methods and concluded that the model and methodology used in the study functioned well with suitable precipitation.  相似文献   

Estimation of Anthropogenic Influences in Groundwater Quality of Shallow Aquifers of Moradabad City,Western Uttar Pradesh     

Naseemus Saba  Rashid Umar  Ahsan Absar 《Journal of the Geological Society of India》2018,91(6):711-716

The present work has been carried out in Moradabad, one of the important cities in the state of Uttar Pradesh. The main focus of the study is to estimate the extent of anthropogenic contamination in shallow groundwater of the area. For this purpose, total 188 groundwater samples collected from handpumps in pre- and post monsoon period of 2012 and 2013 (47 in each season) were analyzed for physico-chemical parameters such as pH, EC, TDS, major cations (Ca, Mg, Na, and K) and anions (Cl, HCO₃, SO₄, NO₃ and F). The results of the analysis suggested that groundwater is slightly alkaline, hard to very hard in nature, average TDS values were found to be more than 1000 mg/l, which gives a clear evidence of anthropogenic influences. To estimate the extent of contamination, the information on relatively unpolluted groundwater systems occurring in different terrains including Ganga plain where the groundwater was relatively unaffected by anthropogenic activities is used. The estimated pristine chemical composition of groundwater of different terrains used in the present study was compared with the groundwater of Moradabad city. This comparison showed that Moradabad city with the highest Na, K, Cl, SO₄ and NO₃ values being 440 mg/l, 96 mg/l, 537 mg/l, 537 mg/ l and 244 mg/l, respectively, is one of the most polluted urban centres within the Ganga plain. It may be suggested that values of > 50 mg/l for Na, > 10 mg/l for K, > 25 mg/l for Cl, > 50 mg/l for SO₄ and > 10 mg/l for NO₃ have their respective sources in anthropogenic activities such as agricultural in the peripheral region, human and animal wastes, leakages from drains and septic tanks, landfill leachates and industrial effluents.  相似文献   

Application of geographical information system for mapping/monitoring seismological hazards in Pakistan     

Mohsin Jamil Butt  Muhammad Haroon Siddiqui 《国际地球制图》2015,30(5):532-544

This study attempts to use the geographic information system (GIS) technique to map and understand the tectonics and crustal structures of Pakistan. Maps of surficial tectonic features and seismological parameters including Moho depth, P_n velocity and P_g velocity are complied. Based on the seismological data-set of the country the earthquake hazard map of Pakistan is also presented by applying regression technique on seismological, geological and topographical parameters. A case study of 8 October 2005 earthquake is used to validate the hazard map. It is envisaged that the developed GIS database would help policy-makers and scientists in natural hazard evaluation, seismic risk assessment and understanding of earthquake occurrences in Pakistan.  相似文献   

A comparative study of heavy metal concentrations in surficial sediments from coastal areas of Karachi, Pakistan     

Qari R  Siddiqui SA  Qureshi NA 《Marine pollution bulletin》2005,50(5):595-599

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Comparative Analysis of Salt Structures in the Southern North Sea,Dutch Offshore,the Netherlands     

Miraj  M. A. F.  Ali  A.  Ahsan  N.  Afgan  Sh.  Saleem  R. F. 《Geotectonics》2020,54(6):807-820

Geotectonics - Comparative analysis of three randomly chosen salt structures (diapir A, diapir B and diapir C) of the Southern North Sea has been presented through the interpretation and...  相似文献   

Nagmati River Sub-watershed Prioritization Using PCA,Integrated PCWS,and AHP: A Case Study     

Siddiqui  Rabab  Said  Saif  Shakeel  Mohammad 《Natural Resources Research》2020,29(4):2411-2430

Prioritization of potential regions that are severely threatened by soil erosion is a prerequisite for formulating and implementing conservation measures and management practices, particularly in fragile semiarid regions. The present study prioritized eight delineated Nagmati sub-watersheds located in the Kutch District of Gujarat State, India, based on three approaches, namely principal component analysis (PCA), integrated PCA with weighted sum (I-PCWS), and analytical hierarchy process (AHP), and on 10 morphometric erosion risk parameters (ERPs). Sub-watersheds were categorized into three priority classes, namely high, medium, and low. PCA retrieved the three most significant ERPs (i.e., length of overland flow, Lo; drainage texture, Dt; and compactness coefficient, Cc) explaining 86.876% of the variance and exhibiting the highest correlation, i.e., r?=?0.961, 0.986, and 0.934 for the first three principal components. Sub-watersheds SW2 and SW7 were rated high priority, SW1 was rated low priority, and the rest were rated medium priority. The I-PCWS approach revealed that sub-watersheds SW2, SW6, and SW7 were in high-priority zone, followed by SW3, SW4, and SW8 in medium-priority zone and SW1 and SW5 in the low-priority zone. The AHP assigned the highest and lowest ranks to “Lo” and “Cc,” respectively, with consistency ratio of 8.1% and principal eigenvalue of 11.075. Results from AHP revealed sub-watershed SW2 to be the highest priority and sub-watersheds SW1 and SW5 to be the lowest priority. Out of eight prioritized sub-watersheds from three approaches, five were found to be the common priority classes, with SW2, SW6, and SW7 demanding urgent implementation of efficient soil conservation measures to prevent further degradation of the identified regions. Results from I-PCWS approach closely complied with the existing landforms within the study area, and this approach was considered more reliable and robust than the other two approaches. The methodology adopted in this study can be applied to different vulnerable, data-scarce regions to sustainably manage and conserve soil erosion through efficiently framed strategies.

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Regolith thickness modeling using a GIS approach for landslide distribution analysis,NW Himalayas     

Muhammad Basharat  Masood Qasim  Muhammad Shafique  Nasir Hameed  Muhammad Tayyib Riaz  Muhammad Rustam Khan 《山地科学学报》2018,15(11):2466-2479

Regolith thickness is considered as a contributing factor for the occurrence of landslides. Although, mostly it is ignored because of complex nature and as it requires more time and resources for investigation. This study aimed to appraise the role of regolith thickness on landslide distribution in the Muzaffarabad and surrounding areas, NW Himalayas. For this purpose regolith thickness samples were evenly collected from all the lithological units at representative sites within different slope and elevation classes in the field. Topographic attributes (slope, aspect, drainage, Topographic Wetness Index, elevation and curvature) were derived from the Digital Elevation Model (DEM) (12.5 m resolution). ArcGIS Model Builder was used to develop the regolith thickness model. Stepwise regression technique was used to explore the spatial variation of regolith thickness using topographic attributes and lithological units. The derived model explains about 88% regolith thickness variation. The model was validated and shows good agreement (70%) between observed and predicted values. Subsequently, the derived regolith model was used to understand the relationship between regolith thickness and landslide distribution. The analysis shows that most of the landslides were located within 1–5 m regolith thickness. However, landslide concentration is highest within 5–10 m regolith thickness, which shows that regolith thickness played a significant role for the occurrence of landslide in the studied area.  相似文献