Chasing Chinese Caterpillar Fungus (Ophiocordyceps sinensis) Harvesters in the Himalayas: Harvesting Practice and Its Conservation Implications in Western Nepal

The Chinese caterpillar fungus is famous for its high market value, unusual life history, and significant medicinal uses. It is harvested by very poor communities and sold for an extraordinarily high price. Most of the studies on this species are focused on therapeutic uses, chemical analyses, ecology, and trade. However, harvesting techniques and intensity of the harvests remain undocumented. We document harvesting techniques, trends of harvest, and perceptions of the Chinese caterpillar fungus harvesters in Dolpa, Nepal, based on surveys, focus-group discussions, and direct observations. Along with increasing market value, intensity of the harvest has been increasing. The Chinese caterpillar fungus harvest has now become the second most important livelihood strategy for the local communities, after agriculture. Reported per-capita harvest based on the first day of collection has declined over the last 4 years, apparently because of the decline in the stock and the increasing number of harvesters.     

Effectiveness of superelastic bars for seismic rehabilitation of clay‐unit masonry walls

This paper presents the results on shaking table tests of half‐scale brick walls performed to investigate the effectiveness of newly developed Cu–Al–Mn superelastic alloy (SEA) bars in retrofitting of historical masonry constructions. Problems associated with conventional steel reinforcing bars lie in degradation of stiffness and strength, or pinching phenomena, under cyclic loading, and presence of large residual cracks in structures during and after intense earthquakes. This paper attempts to resolve the problems by applying newly developed Cu–Al–Mn SEA bars, characterized by large recovery strain, low material cost, and high machinability, as partial replacements for steel bars. Sets of unreinforced, steel reinforced, and SEA‐reinforced specimens are subjected to scaled earthquake excitations in out‐of‐plane direction. Whereas steel‐reinforced specimens showed large residual inclinations, SEA‐reinforced specimens resulted in stable rocking response with slight residual inclinations. Corresponding nonlinear finite element (FE) models are developed to simulate the experimental observations. The FE models are further used to examine the sensitivity of the response with respect to the variations in experimental conditions. Both the experimental and numerical results demonstrate the superiority of Cu–Al–Mn SEA bars to conventional steel reinforcing bars in avoiding pinching phenomena. Copyright © 2012 John Wiley & Sons, Ltd.     

Groundwater Effect on Faulted Rock Mass: An Evaluation of Modi Khola Pressure Tunnel in the Nepal Himalaya

Groundwater has a negative impact not only in construction activity, but also in stability of a tunnel. Severity increases particularly in tunnels passing through fault gouge and breccia, where rock material is completely crushed and extremely weak. Instantaneous collapse and excessive plastic deformation is most likely in tunnels passing through such zones. Often, ‘flowing’ conditions may prevail if groundwater is mixed in the rock mass. This paper presents one such tunnel case in the Nepal Himalaya; i.e. the Modi pressure tunnel. This pressure tunnel passes through a tectonic fault consisting of gouge material. High deformation in the tunnel was observed while excavating the tunnel through the fault. Based on the tunnel deformation that was actually measured, the paper first back-calculates the rock mass strength by analytical approach. Then, the extent of in-situ stress condition in the area is determined by numerical modeling for the rock mass with no ground water in consideration. The ground water effect is then analyzed. We found that the effect of ground water with a static head <1.5 bar pressure may increase the deformation by up to a maximum of 30 %. Finally, we briefly discuss uncertainties related to the input parameter study and used methodologies.     

Detection of slow-moving landslides through automated monitoring of surface deformation using Sentinel-2 satellite imagery

Landslides are one of the most damaging natural hazards and have killed tens of thousands of people around the world over the past decade. Slow-moving landslides, with surface velocities on the order of 10⁻²–10² m a⁻¹, can damage buildings and infrastructure and be precursors to catastrophic collapses. However, due to their slow rates of deformation and at times subtle geomorphic signatures, they are often overlooked in local and large-scale hazard inventories. Here, we present a remote-sensing workflow to automatically map slow-moving landslides using feature tracking of freely and globally available optical satellite imagery. We evaluate this proof-of-concept workflow through three case studies from different environments: the extensively instrumented Slumgullion landslide in the United States, an unstable lateral moraine in Chilean Patagonia and a high-relief landscape in central Nepal. This workflow is able to delineate known landslides and identify previously unknown areas of hillslope deformation, which we consider as candidate slow-moving landslides. Improved mapping of the spatial distribution, character and surface displacement rates of slow-moving landslides will improve our understanding of their role in the multi-hazard chain and their sensitivity to climatic changes and can direct future detailed localised investigations into their dynamics.