Cracks on a house in Joshimath. Photo: Twitter/@LicypriyaK
- The geology of the Himalayas is complex, diverse and risk-prone. Because of Joshimath, today almost everyone acknowledges the fragility of the Himalayas.
- Human activities in the fragile region need a deep scientific understanding and must be accommodated in this reality.
- If we learn from what natural geological processes in the Himalayas teach us and plan settlements on the basis of existing scientific knowledge, long-term solutions are definitely possible.
The geology of the Himalayas is complex, diverse and risk-prone. Today, almost everyone acknowledges the fragility of the Himalayas. Everyone is also concerned about the impacts of climate change on this snowbound region, often called the third pole. Joshimath is news because of the severe damage it is facing, with over 700 buildings vulnerable to collapse. The state ― from the Prime Minister’s Office to the district administration ― is seized with this issue.
Recent GPS-based geodetic studies suggest variation in the rate of convergence and deformation of the Indian plate along the Himalayas, of 5-14 mm/year. In Uttarakhand, the rate of convergence varies between 12 and 14 mm/year in the Garhwal and Kumaon Himalaya respectively. These studies indicate that the maximum crustal strain is near the Main Central Thrust (MCT), which is close to Joshimath.
Such large-scale crustal movements continuously take place and cause a number of earthquakes, some large and others, numerous micro-earthquakes. This region is currently witnessing swarms of micro-seismic events. An average of more than one minor earthquake a week and one micro-earthquake per day is almost the norm. We must understand and accept that no human agency can change this, no matter how powerful the government or administration is. This continuous jolting and movement of the earth from a deeper level causes diverse changes on the surface. Terraces along the river are more vulnerable, old landslide debris may get reactivated, while hard rock which is contiguous deep down will withstand a certain level of weight above it. This is an area where we can put our scientific knowledge together and come up with settlement systems which are compatible with the geological reality, and weave our economy around it.
ISRO releases the Remote sensing images on #Joshimath subsidence:
1)Slow subsidence up to ~ -9 cm recorded between April and November 2022
2) The region subsided around ~ -5 cm within a span of a few days between 27 Dec – 8 Jan pic.twitter.com/is4BtB8Zoc
— All India Radio News (@airnewsalerts) January 13, 2023
Evolution of Settlements
Settlement development in the past was totally different and recognised terrain conditions and experiential knowledge about the region. Communities developed a continuous understanding of the region around them. Systems of ‘Chau-mas’, when cattle would be taken to areas where more grazing lands were available, gave an indication of the terrain around. As existing settlements, which were always in a stable area, became saturated, a new settlement where stable land was identified would develop. Often, the new generation would be encouraged to settle there. Thus, new settlements were not by fiat of administration or the whims of an investor, but scientifically based on the stability of the land, availability of water and other sustenance resources.
This system dramatically changed when the British ‘Permanently Settled’ land, and arbitrarily designated them as forest lands, agricultural lands and habitations. The option to choose a place that was right for a settlement was forfeited. Settlements expanded, most often on agricultural land, which was at least in the control of the people. Most of the land amenable to transformation into farming land and terraces was loose and in many cases remnants of old landslides and eroded materials. These are definitely not suited for construction, especially with heavy reinforced concrete.
After the 1999 Chamoli earthquake, the Geological Survey of India had identified vulnerable settlements and sites and even appealed to the government to identify stable locations for resettlement. However, this was not heeded as new locations would require “denotifying” forest lands, and governments would not take the trouble of going through the process. In the meantime, people forgot about their vulnerabilities and got back to business as usual. With growing pilgrimage and tourist inflow into the region, construction became even more haphazard and risky, even if it brought in more money. Over 70% of buildings are non-engineered and are often built solely by the petty contractor and the mason.
Mapping at a micro level of a diverse range of vulnerability on the ground across the Himalayas is the first step to finding a long-term solution. This would lead to identification of areas where land is stable, and gauging how big a settlement can be, based on other essential aspects like water, access etc.
A new classification of land based on geological realities and people’s needs must be evolved. This can be done rapidly with the vast knowledge and technology available. In the context of global earth movements, meso and micro-level changes on the ground and the uncertainty created by climate change, the huge dams and structures which we think are stable are, unfortunately, not. Many existing projects and investments driving growth in the Himalayas must be set aside. Human activities in the fragile region need a deep scientific understanding and must be accommodated in this reality. This might sound far-fetched, as through protests and appeasement, power and vested interests push for immediate band-aid solutions.
If we learn from what natural geological processes in the Himalayas teach us and plan settlements on the basis of existing scientific knowledge, even if it is administratively and politically inconvenient, long-term solutions are definitely possible. But we live from crisis to crisis, and as a new issue or disaster sets in, the subsidence and disaster of Joshimath will be forgotten.
Unless we as a society are ready to change, more Joshimaths are inevitable.