Factors causing hazards in Nepal Himalaya

The engineering geological factors that cause hazards in the Nepal Himalaya are the following.

1. Active tectonics: continuous collision of Indian and Eurasian plates; active thrusts (MFT, MBT, MCT) cause earthquakes, uplift and fractured rock.
2. Lithology: weak, soft rocks such as phyllite, schist, shale, Siwalik mudstone and loose alluvium; soluble rocks (limestone) with cavities.
3. Geological structure: folds, faults, joints and foliation with adverse orientation; shear zones with crushed rock.
4. Steep slopes and high relief, with deep river valleys and strong river undercutting.
5. Weathering and thick unconsolidated soil cover, colluvium, glacial moraine and talus.
6. Climate: intense monsoon rain, snow melt, freeze-thaw; glacier retreat and glacial lakes.
7. Hydrogeology: high groundwater and pore water pressure, springs and seepage.
8. Seismicity, shaking and liquefaction of loose saturated sand in the Terai and Kathmandu basin.
9. High erosion and sediment transport by rivers; river shifting in the Terai.
10. Human influence: unplanned roads, deforestation, settlements on unstable ground and quarrying.