Effects of Changing Groundwater Levels on Himalayas

Effects of Changing Groundwater Levels on Himalayas

A study by the Indian Institute of Geomagnetism shows that Monsoon rains can influence the heights of Himalayan peaks. Researchers found that groundwater depletion and its subsequent replenishment each year causes several millimeters of movement in some crustal blocks along different fault lines of the Himalayan region.

Key Points

The Geospatial technologies are used for the detection and analysis of glacier water reservoirs, ice melting and seasonal water run-off in Himalayan Mountain Ranges. The control of water resources is an important factor in establishing the timing and volumes of water flow.

The combined GPS and GRACE data suggest a 12% reduction in the rate of the subsurface slip. The subsidence rate is associated with groundwater consumption.

In the Himalaya, seasonal water from glaciers, as well as monsoon precipitation, plays a key role in the deformation of the crust and the seismicity associated with it. The subsidence rate is associated with groundwater consumption.

The researchers have made the combined use of Global Positioning System(GPS) and Gravity Recovery And Climate Experiment (GRACE) data, which has made it possible for them to quantify the variations of hydrologic mass.

The GRACE satellites, launched by the US in 2002, monitor changes in water and snow stores on the continents. This made it possible for the IIG team to study terrestrial hydrology.

The slip occurs at the Main Himalayan Thrust (MHT), due to hydrological variations and human activities, over which there is the periodic release of accumulated strain.

Main Himalayan Thrust

The Main (Greater) Himalayan Thrust or MHT on the Indian plate under thrusts the Eurasian plate along a northerly dipping detachment surface known as Main Himalayan Thrust (MHT) that separates the downgoing Indian plate from the overriding Himalayan wedge. It is a boundary between the Greater and Lesser Himalayas.

The Indian plate is subducting behind the Tibetan cogenetic arc on the northern side and under the Himalayan arc to its south where it gets deflected slightly towards the east. Hence, there is a component of convergence from Tibet and a component of divergence or slab pull in the wedge region leading to a shallow southerly dipping thrust fault known as Main Himalayan Thrust (MHT) separating the accretionary wedge from the main India landmass.