RESEARCH PORTAL

 
RESEARCH INTEREST:

 
Teaching and Supervision:

Engineering Geology and Geo-techniques (GIS & RS application for landslide susceptibility/hazard)

Nepal Himalaya

Containing nine of the world's fourteen highest mountain peaks, Nepal is a true Himalayan kingdom. The Himalaya cover three fourths of the land in Nepal. It is home to some of the highest, remotest, most rugged and most difficult terrain in the world. The loftiest peak in the world -- Mount Everest -- and other high peaks like Lhotse, Nuptse, Annapurna, Dhaulagiri and Manaslu, plus the presence of some exquisitely beautiful trekking routes, attract hundreds of thousands of people from all over the world to this lovely Himalayan destination

The country of Nepal can be divided into three parallel bands running from the northeast towards the southwest. Along the north of Nepal runs the Great Himalayan Range, the highest mountain range in the Himalayan system. This range has an average altitude of about 4,570 m (about 15,000 ft) and remains perpetually snow-covered. On this range rise some of the loftiest mountain peaks in the world -- Mount Everest, Kanchenjunga, Lhotse, Makalu, Cho Oyu, Dhaulagiri, Manaslu, and Annapurna.

Further south runs a complex system of intermediate ranges at an altitude of 8,000-14,000 ft. Prominent ranges in this mountain system include the Mahabharat and Churia ranges. High mountain ranges are interspersed with broad inhabited river valleys. The third and southernmost region is the Terai, a swampy terrain which is the northern extension of the Indian plains.

Panoramic view of the Himalayan range

Geology of Nepal Himalaya

The Himalayan arc extends about 2400 km from Nanga Parbat (8138 m) in the west to Namche Barwa (7756 m) in the east (Le Fort 1996). This region includes Nepal, Bhutan and as well as parts of Pakistan, India, and China. Since 55 Ma, the Himalayan orogen which began with the collision of India and Eurasia at the Paleocene/Eocence epoch (Rowley 1996), has thickened the Indian crust to its present thickness of 70 km (Le Fort 1975). Heim and Gansser (1939), and Gansser (1964) divided the rocks of the Himalaya into four tectonostratigraphic zones that are characterised by distinctive stratigraphy and physiography. From north to south, these are the Sub Himalaya, Lesser Himalaya, Higher Himalaya, and Tibetan Himalaya.

Sub-Himalaya (Siwaliks)
The Sub Himalayan Zone or the Siwaliks of Nepal extends throughout the country from east to west in the southern part. It is delineated by the Himalayan Frontal Thrust (HFT) and Main Boundary Thrust (MBT) in south and north respectively. The Siwaliks consist of very thick (4000 to 6000 m) molasses-like fluvial sedimentary deposits comprising a coarsening-upwards sequence as a whole, which reflects the rising history of the Himalayas (Gansser 1964).

 Lesser Himalaya
The Lesser Himalayas lies in between the Sub-Himalayas and Higher Himalayas separated by MBT and the Main Central Thrust (MCT) respectively. The total width ranges from 60-80 km. The Lesser Himalayas is made up mostly of the unfossiliferous sedimentary and meta-sedimentary rocks; like shale, sandstone, conglomerate, slate, phyllite, schist, quartzite, limestone, dolomite etc. Ranging in age from Precambrian to Miocene. The geology is complicated due to folding, faulting and thrusting and these complications added by the unfossiliferous nature.

Higher Himalaya
This zone extends from the MCT to Tibetan-Tethys Zone and runs throughout the country. This zone consists of almost 10km thick succession of the crystalline rocks, commonly called the Himal Group. This sequence can be divided into four main units, as Kyanite-Sillimanite gneiss, Pyroxenic marble and gneiss, Banded gneiss, and Augen gneiss in the ascending order (Bordet et al. 1972).

Tibetan-Tethys Himalaya
The Tibetan-Tethys Himalayas generally begins from the top of the Higher Himalayan Zone and extends to the north in Tibet. In Nepal these fossiliferous rocks are well developed in Thak Khola (Mustang), Manang and Dolpa area. This zone is about 40 km wide and composed of fossiliferous sedimentary rocks such as shale, sandstone and limestone etc.

Due to the rugged topography, high relief, variable climatic conditions (including extreme weather events) and diverse geological framework Nepal is susceptible to various types of geo-environmental hazards, especially water-induced ones (landslides, debris flows, soil erosion and floods). Water-induced disasters are chronic hazards to Nepalese life during the Monsoon season. The impacts of hazards are further aggravated by human interventions such as deforestation, encroachment of the forest land for cultivation, and infrastructure (road and canals) development in unstable terrain.

Occurrence of landslides in the Lesser Himalaya, central Nepal

Remote Sensing, GIS, Visualisation

Remote Sensing: is the science and art of acquiring information (spectral, spatial and temporal) about material objects, area, or phenomenon, without coming into physical contact with the objects, or area, or phenomenon under investigation (Lillesand & Kiefer 1987).
GIS: is defined as a powerful set of tools for collecting, storing, retrieving at will, displaying, and transforming spatial data, and their attributes (Burrough & McDonnel 1998).
Visualisation: is the cutting edge of new way of thinking about science but its styles vary enormously with context which is so broad a term that to define its role in spatial modelling. The visualisation explore unanticipated outcomes and to refine processes that interact in unanticipated ways; and visualisation is to enable end users with no prior understanding of the science but a deep understating of the problem to engage in using models for prediction (Batty et al. 2004).