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[1] It was reported that a hidden 110-km-long south-dipping fault, named Oldham Fault, was responsible for the 1897 great earthquake ([M.sub.s] 8.7) in the Shillong Plateau by reverse faulting due to 'pop-up' tectonics of the plateau in northeast India. Here we report the results of our geophysical investigations, where we critically examine the crustal structure of the plateau on the basis of gravity modeling and attempt to shed light on the hitherto debated hidden Oldham Fault at the northern boundary of the Shillong Plateau. Our gravity model, constrained by broadband seismological data, suggests that the Moho beneath the Shillong Plateau is at a shallower depth of about 35 km when compared to the Bengal basin to the south and the Assam valley to the north, which is about 42 km. Thinning of the crust under the plateau may be a consequence of the 'pop-up' mechanism. To examine the possible 'pop-up' of the plateau during the great 1897 earthquake, we have estimated the energy released by this earthquake and compared it with the energy required for the 'pop-up' of the plateau, using a simplistic rigid model. It is found that the Shillong Plateau between the Oldham Fault and Dauki-Dapsi Thrust would require an energy of 4.5 x [10.sup.19] J, which does match well with the energy released by the great earthquake of [M.sub.s] = 8.7. Citation: Nayak, G. K., V. K. Rao, H. V. Rambabu, and J. R. Kayal (2008), Pop-up tectonics of the Shillong Plateau in the great 1897 earthquake ([M.sub.s] 8.7): Insights from the gravity in conjunction with the recent seismological results, Tectonics, 27, TC 1018, doi: 10.1029/2006TC002027.

Precipitable water vapor is an important and highly atmospheric variable in temporal and spatially; the knowledge of its variability is important for meteorological and climatological studies. The main objective of this paper, an evaluation of Total Precipitable Water (TPW) retrieved from the Indian National Satellite System (INSAT-3D) data provided by the INSAT-3D Meteorological Data Processing System (IMDPS) at National Satellite Meteorological Centre (NSMC), New Delhi along with collocated Atmospheric Infrared Sounder (AIRS) L3 Standard Physical Retrievals (AIRS-only) during a one year period 2017 over the Indian region. The spatiotemporal distribution of seasonal mean and monthly dependency of the correlation coefficient, bias and root mean square error (RMSE) was computed between INSAT-3D TPW and AIRS retrievals during both daytime and nighttime. The results of the intercomparison reveal that TPW from the INSAT-3D is in very good agreement with the AIRS, that is seasonally distribution of TPW larger in warm seasons (June, July, August) and smaller in the cold season (December, January, February) and monthly dependency of correlation coefficient (> 0.8), bias (2–3 mm) and RMSE (< 5 mm) in all months during both daytime and nighttime, except June, July, August over coastal regions of Arabian Sea and Bay of Bengal shows degradation performance. However, the statistical analysis between INSAT-3D with respect to AIRS TPW retrieval during both daytime and nighttime shows that more reliable except during cloudy days. In addition to it, a similar analysis is carried out to assess the relative performance of INSAT-3D retrieved TPW with respect to 10 Global Navigational Satellite System (GNSS) over the Indian subcontinent obtained from the NSMC the period from 1st January to 30 June 2017 on hourly. In this analysis, for each station time series, diurnal variations of TPW and monthly, seasonal distribution of the Taylor diagram was carried out between INSAT-3D and GNSS retrievals. INSAT-3D and 10 GNSS stations gave comparable accuracies during the months of March to June whereas the quality degrades in January and February months resulting in slight error. It might be caused by the in the winter season the surface emissivity could be one region for more degraded performance under the drier condition it brings in more uncertainties in surface emissivity. Overall, these results give good confidence in the quality and potential of INSAT-3D over the Indian region and can be used in weather forecasting and nowcasting applications. [ABSTRACT FROM AUTHOR]

Melon fly is a serious pest of cucurbits all over the world causing huge losses to yield. However, the only exception is the chayote fruit ( Sechium edule) that shows resistance to melon fly infestation. Studies on culture of melon fly indicated the absence of plant traits resisting oviposition on chayote fruit. However, the melon fly was unable to complete its life cycle successfully on chayote showing that factors inhibiting larval development in melon fly could be attributed to biochemical constituents. Studies were, therefore, carried out to compare the biochemical responses of chayote, a melon fly resistant species and bitter gourd, a susceptible species to melon fly infestation with regard to the levels of phenolic acids and activities of the enzymes of phenylpropanoid pathway ( PPP) leading to synthesis of lignin. The resistant chayote exhibited significantly higher accumulation of lignin associated with higher activities of phenylalanine ammonia-lyase ( PAL), tyrosine ammonia-lyase ( TAL), cinnamyl alcohol dehydrogenase ( CAD) and peroxidase ( POD). On the contrary, the susceptible bitter gourd recorded lower activities of PAL, CAD and POD and a decreasing trend of TAL during infestation associated with a lower lignin content. The monomer composition of lignin in the resistant chayote showed twofold higher level of guaiacyl (G) and syringyl (S) units compared to susceptible bitter gourd and the G/S ratio during infestation increased in chayote while decreasing in bitter gourd. The levels of PPP intermediates, p-coumaric acid was higher in chayote while p-hydroxy benzoic acid, a chemo-attractant, was higher in bitter gourd. Incorporation of p-coumaric acid in the larval diet strongly inhibited larval growth even as p-hydroxy benzoic acid promoted growth confirming the direct role of p-coumaric acid in conferring resistance to chayote. The level of salicylic acid, a signal molecule involved in induction of defence response, was higher in chayote compared to bitter gourd. Chayote also exhibited higher level of activity of POD in the phloem exudates compared to bitter gourd. The higher concentration of sugars in exudates of chayote might act like signalling molecules causing activation of plant genes, especially of the phenylpropanoid biosynthesis pathway and possibly produce an osmotic effect inducing resistance against the melon fly. Thus, the study revealed that the resistance in chayote to melon fly infestation is a complex, multi-layered process in which the activities of PPP enzymes generating phenolic intermediates leading to lignin biosynthesis and the composition of exudates appear to play significant roles. Besides, the study also indicated that different forms of lignin might play a role in the resistance of chayote against melon fly infestation. [ABSTRACT FROM AUTHOR]