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991.
An entry in the Tarikh-i-Hassan records that in 883 AD during the reign of King Avantivarman (855–883) an earthquake in Kashmir triggered a landslide that impounded the River Jhelum and flooded the Kashmir Valley. Kalhana’s Rajatarangini provides abundant details about how the ninth century engineer Suyya both cleared the natural dam, drained the valley and instituted numerous irrigation works. We identify the landslide(s) responsible for this Medieval flood and from twentieth century discharge statistics of the Jhelum calculate that it would have taken at least 2 years to flood the Kashmir Valley to near Anantnag. This presents a chronological difficulty, for the causal earthquake could not have occurred in the last 4 months of Avantivarman’s rule, and we conclude that it must have occurred much earlier, perhaps before the start of his reign. The flood occurred during a period of widespread temple building using massive uncemented limestone megablocks, capped by monolithic multi-ton roofs. Many of these magnificent temples, now in ruinous condition, are located close to the shores of the inferred Medieval flood level, suggesting that the transport of construction materials for these temples may have been ferried by barge from distant quarries. Historians and archaeologists have attributed the partial collapse of these temples to malicious damage by subsequent occupants of the valley, but the misalignment of blocks at lower levels within each edifice in recent earthquakes suggests that their lateral offsets are the result of jostling during prolonged shaking in historical earthquakes. From the serendipitous entrapment of datable materials beneath fallen blocks from Kashmir’s ninth century temples we can, in principle, identify the times of historical earthquakes. We chose the ruined Sugandhesa temple near Patan to test this hypothesis. Preliminary results indicate collapse in the tenth or eleventh century, and significant damage in 1885, with at least one intervening earthquake possibly in the seventieth century. 相似文献
992.
Comparative evaluation of performances of two versions of NCEP climate forecast system in predicting Indian summer monsoon rainfall 总被引:1,自引:0,他引:1
Nachiketa Acharya Makarand A. Kulkarni Uma C. Mohanty Ankita Singh 《Acta Geophysica》2014,62(1):199-219
The operational prediction of climatic variables in monthly-to-seasonal scales has been issued by National Centers for Environmental Prediction (NCEP) through Climate Forecast System model (CFSv1) since 2004. After incorporating significant changes, a new version of this model (CFSv2) was released in 2011. The present study is based on the comparative evaluation of performances of CFSv2 and CFSv1 for the southwest monsoon season (June-July-August-September, JJAS) over India with May initial condition during 1982–2009. It was observed that CFSv2 has improved over CFSv1 in simulating the observed monsoon rainfall climatology and inter annual variability. The movement of the cell of Walker circulation in years of excessive and deficient rainfall is better captured in CFSv2, as well. The observed teleconnection pattern between ISMR-sea surface temperature (SST) is also better captured in CFSv2. The overall results suggest that the changes incorporated in CFSv1 through the development of CFSv2 have resulted in an improved prediction of ISMR.21 相似文献
993.
Prashant Patil Sarnam Singh V. K. Dadhwal 《Journal of the Indian Society of Remote Sensing》2012,40(1):37-46
Spectral modeling of above ground biomass (AGB) with field data collected in 48 field sites representing moist deciduous forest
in Surat district is reported. Models were generated using LISS-III and MODIS data. The plot-wise field data was aggregated
to MODIS pixel (250 m) using area weightages of forest/vegetation. The study reports that above ground phytomass varied from
6.13 t/ha to 389.166 t/ha while AGB phytomass estimated using area-weights for sites of 250×250 m, ranged from 5.534 t/ha
to 134.082 t/ha. The contribution of bamboo in AGB has been found very high. The analysis indicated that the highest correlation
between AGB phytomass and red band (R) of MODIS satellite data of October was (R2=0.7823) and R2=0.6998 with both NDVI of October data as well as NDVImax. High correlation (R2=0.402) with IR band of February month was also found. The phytomass range obtained by using MODIS data varies from 0.147 t/ha
to 182.16 t/ha. The mean biomass is 40.50 t/ha. Total biomass is 31.44 Mt. The mean Carbon density is 19.44 tC/ha in forest
areas. The study is validation of region-wise spectral modeling approach that will be adopted for mapping vegetation carbon
pool of the India under National Carbon Project of ISRO-Geosphere Biosphere Programme. 相似文献
994.
Mehul R. Pandya Raghavendra Pratap Singh Sushma Panigrahy Jai Singh Parihar 《Journal of the Indian Society of Remote Sensing》2012,40(2):215-223
Quantitative remote sensing involving accurate estimation of vegetation properties relies greatly on the measurements of the
near infrared (NIR) channel because of unique interaction property between light and leaf. It is generally assumed that the
NIR measurements are made in the absence of atmospheric absorption. However, relatively weak water vapour absorption features
still persist in the NIR channel, which has bearing on the quantitative estimates of the vegetation properties and long-term
data series. This paper reports the results of a study that was carried out to infer the possible influence of the atmospheric
water vapour (WV) on the NIR measurements (0.77–0.86 μm) of Indian Remote Sensing (IRS) satellite sensors through radiative
transfer simulations using MODTRAN model. The study also suggests and evaluates the alternate band-positions for the NIR channel
to improve the IRS NIR measurements. It was observed that the water absorption features present around 0.810 μm reduces the
WV transmission of IRS NIR channel from 1 to 0.91 when atmospheric WV content increased from 0 to 6 g/cm2 and thus hampered the NIR reflectance by 14% as compared to reference signal. A significant improvement of the order of 6.5
to 12% in the NIR reflectance and 4.2 to 7% in NDVI was observed, when IRS NIR channel was split into NIR1 (0.775–0.805 μm)
and NIR2 (0.845–0.875 μm) channels by avoiding the WV absorption features. The companion paper in this issue (Pandya et al.
2011) will support results of this simulation study through the EO1-Hyperion data analysis. 相似文献
995.
In this paper, a methodology that can be employed to simulate radionuclide migration through unsaturated soils, under laboratory
conditions, has been developed and reported. This was achieved with the help of a specially designed half-cell setup to study
diffusion characteristics of inactive forms of Cs+, Sr+2 and Co+2 in two different types of soils, corresponding to their different compaction states. It has been noted that the apparent
diffusion coefficient strongly depends on the volumetric water content of the soil. However, increase of the apparent diffusion
coefficient for higher volumetric water contents is found to be much less as compared to the lower volumetric water contents. 相似文献
996.
P. K. Misra S. Kishore S. K. Singh A. K. Jauhri 《Journal of the Geological Society of India》2009,74(1):139-140
Discussion
Rhodophycean algae from the Lower Cretaceous of the Cauvery Basin, South India by P.K. Misra, S. Kishore, S.K. Singh and A.K. Jauhri. Jour. Geol. Soc. India, v.73, 2009, pp.325–334 相似文献997.
Arvind K. Mishra Y. K. Nigam Deepanshu R. Singh 《Journal of the Geological Society of India》2017,89(1):87-90
Except for very deep-seated deposits, open cast mining method has been recognized as the safest and most productive mode for mining minerals. Ever growing demand in minerals and coal has compelled the mine operators to increase the size of mine, which has resulted in an increasing trend towards large capacity open cast projects. Explosives and blasting techniques play a significant role in efficient opencast mining operations. There have been constant technological developments towards safer, faster, economical and more efficient blasting systems. Further, globally increased competitiveness has necessitated to carryout blasts in such a way that the desired degree of fragmentation is achieved in the primary blast, with minimum undesired side effects such as ground vibration, air blast/noise, flyrock, generation of oversize boulders, formation of toe, and over break or back break. Hence, the ultimate objective of the blasting engineer is to ensure that the blasts are carried out in an eco-friendly manner. This paper presents a case study of limestone mine where a controlled blasting was conducted near a green structure of wagon tippler (at 2 m) being constructed for foundation work of belt conveyor as the mine management wants to double the existing production. This paper deals with controlled blast design and its implementation using electronic detonators with signature hole technique. 相似文献
998.
999.
Prakash K. Singh Vijay K. Singh M. P. Singh P. K. Rajak 《Journal of the Geological Society of India》2017,90(1):9-19
The Tertiary basins of Gujarat have always been a potential target for their hydrocarbon resources. The lignite resources of the region have also been an important field of research. The present paper presents the results of the petrological study carried out on the lignites of the Saurashtra basin. For this purpose samples were collected from lower and upper lignite seams from the Surkha lignite mine of Bhavnagar, Saurashtra. These samples were subjected to detailed petrographic analysis (both maceral and microlithotype). The study reveals that these lignites are dominantly composed of huminite group macerals while liptinite and inertinite group macerals occur in subordinate amounts. These lignites have attained a thermal maturity up to 0.28-0.30 percent vitrinite reflectance (VRr) which classifies them as ‘low rank C’ coals. Moreover, Bhavnagar lower lignite seam shows relatively less gelification as compared to the upper seam which suffered relatively more biochemical degradation. These lignites are characterized by high gelification index (GI) and low tissue preservation index (TPI).With the help of petrography based facies models an attempt has been made to reconstruct the environment of the paleomire of these lignites. 相似文献
1000.
K. N. D. Prasad N. Srinivas A. E. Meshram A. P. Singh V. M. Tiwari 《Journal of the Geological Society of India》2017,90(6):704-710
Koyna-Warna Region (KWR) is one of the known sites for reservoir triggered seismicity. The continued triggered seismicity over the five decades is restricted to a region of about 600–700 sq. km, which provides a unique opportunity to monitor geophysical anomalies likely to be associated with seismicity of the region. Present study confers temporal gravity changes recorded by gPhone and GRACE satellite and interprets observed changes in conjunction with seismological, geodetic (cGPS) observations and groundwater level measurements. GRACE data suggest that seasonal vertical deformation due to hydrological loading is ~ 2 cm, which corroborates with continuous GPS observations. Seasonal hydrological loading of the region, which is in a phase of reservoir loading, might be influencing the critically stressed KWR leading to the seasonal seismicity of the region. The gPhone gravity data distinctly show co-seismic gravity signals for eight earthquakes of Mw > 2 and gravity anomalies show positive correlation on a logarithmic scale with earthquake released energy. To investigate the cause of gravity changes, an estimate is made for 14th April 2012 earthquake for Mw 4.8 using fault dislocation model. The recorded gravity changes of 189 μGal by gPhone located at a distance of 28 km from the hypocentre is much more than the estimate of ~0.1 μGal calculated for Mw 4.8 Koyna earthquake. Therefore, it is inferred that co-seismic gravity signals for eight earthquakes are primarily caused due to redistribution of mass at shallow depth. 相似文献