Deformability characteristics of a rock mass under true-triaxial stress compression

In this paper an experimental study was planned on rock mass model with three joint sets under triaxial and true-triaxial stress states to assess the influence of joint geometry and stress ratios on deformational behaviour of rock mass. The physical models were composed of three continuous orthogonal joint sets in which joint set-I was inclined at angle θ=0°, 20°, 40°, 60°, 80° and 90° with x-axis, joint set-II was produced at staggering s=0.5 and joint set-III was kept always vertical. Thus, rock mass models with medium interlocked smooth joints (ϕ _j =36.8°) were simulated under true triaxial compression (σ₁>σ₂>σ₃). Modulus of rock mass shows anisotropy with joint inclination θ which diminishes with increase in σ₂/σ₃ ratio. The rock mass at θ=60° shows the highest modulus enhancement (599.9%) whereas it is minimum (32.3%) at θ=90°. Further two empirical expressions for estimation of deformation modulus were suggested based on experimental results, which were developed by incorporating two basic concepts, e.g. Janbu’s coefficients and joint factor, J _f.     

Structure and evolution of the Cauvery Shear Zone system, Southern Granulite Terrain, India: Evidence from deep seismic and other geophysical studies

The Southern Granulite Terrain with exposed Archean lower crustal rocks is studied using various geophysical tools. The crustal structure derived from seismic reflection and refraction/wide-angle reflection studies is used to understand the tectonic evolution of the region. Deep seismic reflection section along the Kolattur–Palani segment shows an oppositely dipping reflection fabric near the Moyar–Bhavani shear zone, which is interpreted as a signature of collision between the Dharwar craton and another crustal block in the south. The thickened crust due to collision was delaminated during the orogenic collapse and modified the central part, covering the Cauvery Shear Zone system, located between the Moyar–Bhavani and Karur–Oddanchatram shear zones. The delaminated lower crust is altered by magmatic underplating as evidenced by the high velocity layer just above the Moho. The velocity model of the region indicates crustal thickening at the boundary of the Dharwar craton and Moyar–Bhavani shear zone and thinning further south. Back-scattered seismic wave field with negative moveout and the Moho-offset indicate the spatial location and strike-slip nature of the shear zones. Present study suggests that the late Archean collision and suturing of the Dharwar craton with the southern crustal block at the Moyar–Bhavani shear zone may be responsible for the evolution of late Archean granulites. Late Neoproterozoic rifting is observed along the paleo-fault zones. The seismic studies constrained by gravity, magnetic and magnetotelluric data suggest that the Moyar–Bhavani and Karur–Oddanchatram shear zones of the Cauvery Shear Zone system mark terrane boundaries/suture zones.     

Agricultural Extension in Balochistan,Pakistan： Date Palm Farmers＇ Access and Satisfaction

This study analyzed information gathered from 200 date palm households in the mountainous Panjgur District of Balochistan in Pakistan with the aim of determining date farmers＇ access to and satisfaction with agricultural extension services. Information was collected through a structured questionnaire survey, group discussions and semi- structured personal interviews. The findings of the analysis revealed very poor access to extension services. The results of logistic regression analysis identified five variables out of six which significantly influence date farmers＇ access to extension services： household bead＇s age, household bead＇s literacy, number of date palm trees owned, mostly inherited date palm trees, and percentage of dead date palm trees. The overwhelming majority of farmers were dissatisfied with all three main types of extension services being provided by public extension officials. Explanations for this as well as for associations between access to extension services and the six independent variables are provided. Important policy conclusions are drawn based on the findings.     

An assessment of Yarsagumba (Ophiocordyceps sinensis) collection in Dhorpatan Hunting Reserve,Nepal

Yarsagumba （Ophiocordyceps sinensis）, an endemic species to the Himalayas and Tibetan Plateau, is one of the most valuable medicinal mushrooms in the world. In Nepal, it is distributed largely in isolated patches of alpine grasslands of 3,000-5,000 m elevation. Although it is reported from 27 northernmost districts of Nepal, the local distribution pattern of this species is largely unknown. Furthermore, the collection system and local management regime of this species are not well documented. We conducted a field survey at Dhorpatan Hunting Reserve （DHR） among the different stakeholders in January-June 2012 to assess collection sites, patterns and trends and to understand the management regime. We estimated that about 75 kg of Yarsagumba is collected every year from DHR and the amount has been declining since 2008. To manage the resource, locals have initiated regulating the collection by issuing permits, taxing to the collectors, and monitoring the activities of harvesters with the help of park authorities. The revenue generated at local level from the permits has been used for community developmental activities.     

Evaluating the performance of climate models in reproducing the hydrological characteristics of rainfall events

ABSTRACT

Rainfall events largely control hydrological processes occurring on and in the ground, but the performance of climate models in reproducing rainfall events has not been investigated enough to guide selection among the models when making hydrological projections. We proposed to compare the durations, intensities, and pause periods, as well as depths of rainfall events when assessing the accuracy of general circulation models (GCMs) in reproducing the hydrological characteristics of observed rainfall. We also compared the sizes of design storm events and the frequency and severity of drought to demonstrate the consequences of GCM selection. The results show that rainfall and extreme hydrological event projections could significantly vary depending on climate model selection and weather stations, suggesting the need for a careful and comprehensive evaluation of GCM in the hydrological analysis of climate change. The proposed methods are expected to help to improve the accuracy of future hydrological projections for water resources planning.