A decadal historical satellite data analysis for flood hazard evaluation: A case study of Bihar (North India)          下载免费PDF全文

Panchagnula Manjusree  Chandra Mohan Bhatt  Asiya Begum  Goru Srinivasa Rao  Veerubhotla Bhanumurthy 《Singapore journal of tropical geography》2015,36(3):308-323

Flood is one of the major recurrent natural disasters faced by the state of Bihar in north India. In the present study the authors assess the severity of flood hazard in Bihar, using 128 decadal historical satellite datasets acquired during different flood magnitudes during 1998 to 2010. The satellite‐based observations have been analysed in conjunction with the hydrological data, for assessing the frequency of inundation, severity of flood hazard and cropped land under flood hazard. This study assesses the spatial distribution of flooding and creation of systematic flood hazard database, which can be analysed from a spatial dimension in GIS. It is observed that about 24.56 lakh ha of the state's area and about 15.85 lakh ha of the cropped area are vulnerable to flood hazard. North Bihar is more vulnerable to flooding; 8 of the 10 areas identified as worst flood‐affected districts lie in this region.  相似文献   

Review Paper: A semi‐empirical model of strain sensitivity for 4D seismic interpretation          下载免费PDF全文

Colin MacBeth  Asiya Kudarova  Paul Hatchell 《Geophysical Prospecting》2018,66(7):1327-1348

We reformulate the original model of Hatchell and Bourne and Røste, Stovas and Landrø that couples fractional velocity change to subsurface strain via a fundamental constant R. The new model combines elastic compressibility of a dual‐porosity system for a sand–shale mixture with horizontal planes of inter‐granular weakness. The majority of observed R‐factor magnitudes from post‐stack 4D seismic data in both the reservoir and overburden can thus be explained. R is predicted to depend strongly on lithology and also initial strain state. The model is also extended to predict the observed angle‐dependence of time‐lapse time‐shifts from pre‐stack data. An expression for the gradient of time‐shift with incidence angle is obtained in terms of the background V_P/V_S, and also the ratio of tangential to normal compliances B_T/B_N representing loss or creation of inter‐granular coupling. If accurately estimated from data, this compliance ratio can be used as an additional parameter to assess the post‐production state of the overburden. It is concluded that whilst R remains the over‐arching parameter controlling the magnitude of time‐shifts measured from 4D seismic data, B_T/B_N is a subtler parameter that may also prove of future value.  相似文献   

OH-defects in multiple-doped orthoenstatite at 4–8 GPa: filling the gap between pure and natural systems     

Roland Stalder  Asiya Karimova  Jürgen Konzett 《Contributions to Mineralogy and Petrology》2015,169(4):1-10

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