Geomorphology : news and updates

What is the News?

The Supreme Court of India has refused to stop the demolition of over 10,000 settlements encroaching on forests in the Aravalli range in Haryana’s Faridabad district.

What was the case about?

• Public interest litigation was filed in the Supreme Court seeking a stay on the demolition of the settlements.
• The petitioners had also asked the court for more time to produce documents to claim rehabilitation.

What did the Supreme Court say?

• The Supreme Court has refused to stop the demolition. It said that the residents had enough time to prove their claims in accordance with a notification issued by Haryana in 2020.
• The court also said the onus was on the State to rehabilitate the residents in compliance with a 2003 scheme. Hence, demolition should continue.

About Aravalli Range:

Read Also :-Are courts encroaching on the powers of the executive?

• Aravalli Range is the oldest mountain range in India and one of the oldest mountain systems in the world.
• The Aravalli range is spread across the states of Gujarat, Rajasthan, Haryana and Delhi.
• History:
  • The natural history of the Aravalli Range dates back to times when the Indian Plate was separated from the Eurasian Plate by an ocean.
  • Mining of copper and other metals in the Aravalli range dates back to at least the 5th century BCE, based on carbon dating.
• Rivers: The three major rivers and their tributaries flow from the Aravalli. Namely Banas and Sahibi rivers which are tributaries of Yamuna, as well as Luni River which flows into the Rann of Kutch.
• Highest Peak: Guru Shikhar Peak on Mount Abu is the highest peak in the Aravalli Range (1,722 m).

Source: The Hindu

Introduction

An Earthquake of 6.4 magnitude hit Assam on April 28th, 2021. It caused sufficient damage to buildings and property but fortunately, no fatalities were reported. The northeastern region has a peculiar record of experiencing earthquakes at regular intervals due to its unique geographical location. The state of Assam itself witnessed two great earthquakes (Magnitude >8) in 1897 and 1950.

In this article, we will try to ascertain the reasons behind the occurrence of earthquakes, their brutal impacts, and the vulnerability of the northeast region that converts it into a disaster. Further, we will try to find out what rational measures should be taken for developing robust earthquake resilience.

How does an earthquake occur?

• Firstly, an earthquake occurs when there is a sudden release of energy in the Earth’s lithosphere that creates seismic waves.
• Secondly, the release of energy occurs along a fault. A fault is a sharp break in the crustal rocks. 
• Thirdly, rocks along a fault tend to move in opposite directions. As the overlying rock strata press them, the friction locks them together. However, their tendency to move apart at some point in time overcomes the friction. 
• Fourthly, as a result, the blocks get deformed, and eventually, they slide past one another abruptly. This causes a release of energy, and the energy waves travel in all directions.

Read More – Basics of Earthquake

Current Scenario

• Recently an earthquake of magnitude 6.4 on the Richter scale hit Assam.  It occurred near Dhekiajuli in the Sonitpur district of Assam, 80 kilometres northeast of Guwahati.
• Following the main tremors, six aftershocks (of magnitude ranging from 3.2 to 4.7) also occurred within two-and-a-half hours. 
• The National Centre for Seismology (NCS) recently mentioned that these tremors were attributed to the Kopili Fault Zone.

About Kopili Fault Zone

• It is a 300-km northwest-southeast trending fault. It extends from the western part of Manipur to the tri-junction of Bhutan, Arunachal Pradesh, and Assam.
• The zone has witnessed many seismic activities in the past. This includes the 1869 earthquake (7.8 magnitude) and the 1943 earthquake (7.3 magnitude).
• The zone is located closer to Himalayan Frontal Thrust (HFT).
  •  It is a geological fault along the boundary of the Indian and Eurasian tectonic plates.

Source: ISR

History of Earthquakes in the Northeast Region

• The North-Eastern part of the country continues to experience moderate to large earthquakes at frequent intervals. This includes the two great earthquakes -1897 Shillong (Magnitude – 8.7) and 1950 Assam-Tibet (Magnitude – 8.6).
• On average, the region experiences an earthquake with a magnitude greater than 6.0 every year.

Vulnerability of Northeast Region to Earthquake

• High Seismicity Level: Northeast is located in the highest seismological zone. The Kopili Fault Zone is a seismically active area, so it falls into the highest Seismic Hazard Zone V. It is associated with collisional tectonics because the Indian Plate is subducting beneath the Eurasian Plate. 
• Nature of Soil: Kopili fault zone and its neighbouring areas are characterized by alluvial soils. These alluvial soil have a higher potential of trapping seismic waves. Thus making the region the most earthquake-prone zone in North East India.
• Terrain: The region has a significant amount of mountainous terrain that demands explosions for building a tunnel, road, etc. infrastructure. This enhances the probability of earthquakes.
• Untapped Potential: The region has not seen robust development like the rest of India. Thus, a greater number of development projects like mining, dam construction, etc. in the region are under planning. It may enhance earthquake probability in the future.
• High-technology equipment and tools: There has been an increase in the use of high-technology equipment and tools in the manufacturing and service industries. This has made them susceptible to disruption even by moderate ground shaking.
• Unscientific Buildings: Many buildings in the cities of Shillong, Gangtok etc. are constructed on the sloping ground. That too by excavating some part of the hill. 
  • The open ground storey, heavy overhangs, heavy rooftops, and irregular plan shapes are common in buildings that make them seismically more vulnerable.
• Policy gap: There is a considerable knowledge and policy gap regarding earthquakes in the Northeast. Even a good knowledge about the Kopili fault did not result in disaster reduction policies.

Earthquake Zonation in India

• India has been divided into four seismic zones (II, III, IV, and V) based on scientific inputs relating to seismicity, earthquakes that occurred in the past and the tectonic setup of the region.

Source: National Institute of Disaster Management

General reasons behind the occurrence of earthquakes

• Firstly, Tectonic Activities: Sliding of rocks along a fault plane can cause sudden shaking of the ground, resulting in an earthquake.
• Secondly, Volcanic activities: A special class of tectonic earthquakes is sometimes recognized as a volcanic earthquake. However, these are confined to areas of active volcanoes.
• Thirdly, Human-Induced: Minor earthquakes and tremors that are caused by human activity like mining, large-scale petroleum extraction, artificial lakes (reservoirs), nuclear tests, etc.
  • Collapse Earthquakes: In the areas of intense mining activity, sometimes the roofs of underground mines collapse causing minor tremors.
  • Explosion Earthquakes: Ground shaking may also occur due to the explosion of chemical or nuclear devices. Such tremors are called explosion earthquakes.
  • Reservoir-induced: The earthquakes that occur in the areas of large reservoirs are referred to as reservoir-induced earthquakes.

Impact of Earthquake

1. Loss of Human Lives: The earthquakes have eaten up thousands of precious human lives across the world.
   • Around 1,542 deaths occurred in Assam during the 1897 Great Earthquake. 
2. Infrastructural Damage: Several houses and buildings were damaged after an earthquake of magnitude 6.4 hit Assam.
   • Similarly, the great Assam earthquake (1897) reduced all masonry buildings to debris within a region of northeastern India. This is roughly the size of England.
3. Initiating another disaster: The 1950 Assam earthquake caused huge landslides. These landslides in turn blocked many rivers in the mountainous region and caused floods. 
4. Land Degradation: The recent Kolipi Fault zone earthquake caused cracks in a paddy field situated in Tatkal Basti village of Misamari, a town on the Assam-Arunachal Pradesh foothills.
5. Economic Losses:  A significant amount is spent on reconstructing the lost infrastructure, rehabilitation of masses, and providing relief support to the impacted people.

Suggestions

• Firstly, the government has to fix the knowledge and policy gap regarding earthquakes in North East India.
• Secondly, the government has to build an effective Earthquake mitigation plan. This would involve constructing resilient infrastructure among other things. 
  • For instance, the Delhi Metro pillar can easily withstand an earthquake of magnitude 9.
• Thirdly, an integrated disaster management plan should be developed for the North East. This plan will help in tackling these types of high-intensity earthquakes.
• Fourthly, due adherence to Environmental impact assessment must be observed before initiating mining or dam construction.
• Fifthly, more funding should be given to Earthquake planning and mitigating agencies to improve disaster management potential.
  • For instance, the National Centre for Seismology has developed ‘India Quake’. An App for Earthquake Parameter Dissemination 

Conclusion

Being in the seismic zone 5, earthquakes are bound to occur in the northeast region. The government is incapable of stopping their occurrence. Although it can definitely curtail their adverse impact by developing robust resilience in consonance with Sendai Framework for Disaster Risk Reduction 2015-2030.

What is the News?

The National Centre for Seismology (NCS) has said that the tremors in Assam can be attributed to the Kopili Fault Zone. The fault zone is located closer to Himalayan Frontal Thrust (HFT).

About the tremors in Assam:

Recently an earthquake of magnitude 6.4 on the Richter scale hit Assam. Following the main tremors, six aftershocks (of magnitude ranging from 3.2 to 4.7) also occurred within two-and-a-half hours. The NCS recently mentioned that these tremors were attributed to the Kopili Fault Zone.

About Himalayan Frontal Thrust (HFT):

It is also known as the Main Frontal Thrust (MFT). It is a geological fault along the boundary of the Indian and Eurasian tectonic plates.

Way Forward:

• Firstly, the government has to fix the knowledge and policy gap regarding earthquakes in North East India.
• Secondly, the government has to build an effective Earthquake mitigation plan.
• Thirdly, an integrated disaster management plan should be developed for the North East. This plan will help in tackling these types of high-intensity earthquakes.

Source: Down To Earth

What is the News?

The Prime Minister through a tweet asked everyone to visit a tulip garden in Jammu and Kashmir. The garden is located at the foothills of the Zabarwan range.

About the Tulip garden 

The tulip garden is located at the foothills of the Zabarwan range. It is Asia’s largest tulip garden, spreading over an area of about 30 hectares.

This garden is home to more than 64 varieties of tulips in bloom. Further, it was started in 2007 to boost floriculture and tourism in Kashmir Valley.

About Zabarwan Range:

• It is a short sub-mountain range between Pir Panjal and Great Himalayan Range. It is located in the central part of the Kashmir Valley.
• The Highest Peak: The highest peak of this range is Mahadev Peak at 13,013 feet (3,966 m). It forms the distant background of the eastern mountain wall.
• Temple: The Shankaracharya Temple is built on the edge of the central part of the Zabarwan Range.
• Significance: On the northern slopes of the central part of the range there are three Mughal gardens built by Emperor Shah Jahan. These include Chashma Shahi, Nishat Bagh, and Shalimar Garden alongside the Pari Mahal.
• Wildlife: The Zabarwan mountain range possesses great Himalayan features with rich wildlife. The Dachigam National Park is the main feature of the range.
  • The Dachigam National Park holds the last viable population of Kashmir stag (Hangul). Further, the National Park also has the largest population of black bear in Asia.

 Source: The Hindu

What is the news?

Ecuador’s Sangay volcano erupted and blew clouds of ash as high as 8,500 meters (8.5 km) into the sky.

 About Sangay Volcano:

• Sangay is an active stratovolcano in central Ecuador. It is one of the most active volcanoes in the world.
  • Stratovolcanoes or composite volcanoes are conical volcanoes. They are composed of multiple layers of intermediate to lava, ash, and other volcanic debris.
• Location: Sangay Volcano is located on the eastern edge of the Andes Mountains.
  • The Andes is the longest mountain range in the world. It boasts some of the highest peaks. The range is also known for its volcanoes.
  • The Andes extend from north to south through seven South American countries: Venezuela, Colombia, Ecuador, Peru, Bolivia, Chile, and Argentina.
• Significance: Sangay Volcano hosts a significant biological community. Therefore, since 1983, its ecological community has been protected as part of the Sangay National Park, a UNESCO World Heritage Site.

About Ecuador:

• Ecuador is a country in the northwestern part of South America. It is bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west.
• Ecuador also includes the Galápagos Islands in the Pacific which is about 1,000 kilometres west of the mainland.
• Ecuador is a part of the Pacific Rim’s “Ring of Fire” region. It has eight volcanoes in its territory.

Source: Indian Express

What is the News?

According to glaciologists and experts, the cause of flash floods in Uttarakhand Chamoli district was most probably a landslip(Landslide) and not a glacial lake burst.

Why are experts calling it a Landslide and not a glacial lake burst?

• The glacial lake outburst flood(GLOF) occurs when a natural lake, formed from a glacial ice melt and the glacial lake is breached. However, available satellite images do not show the presence of a glacial lake before the flooding event.
• Moreover, the Central Water Commission(CWC) monitors and prepares monthly reports on the state of glacial lakes and waterbodies measuring 10 hectares and above via satellite. Nothing out of the ordinary was observed by CWC.

Then, what might have caused the flooding?

• There was a hanging glacier and on top of the glacier was a huge rock mass.
• The rock mass became loosened due to freezing, thawing, and temperature variation. It came crashing down, creating pressure on the hanging part of the glacier. The fresh snowfall had also been added to the weight over the hanging glacier.
• This hanging glacier broke off due to gravitational pull, slid down with the entire rock mass. It slowed down near the base of the valley, where the Raunthi Gadhera stream flows.
• As the huge mass slowed a bit, then stopped, it blocked the water of the stream and the water quantum kept increasing. This damming up of the stream increased to such an extent that it breached the whole accumulated mass of water.
• Hence, this whole mass of water, boulders, and rock mass came crashing down with force towards the Rishi Ganga dam site. It caused massive damage to the under-construction Tapovan hydel project and caused floods.

Source: The Hindu

 More Related post

https://forumias.com/blog/glacial-lake-outburst-flood-glof-in-uttarakhand-explained/

https://forumias.com/blog/glacial-lake-outburst-floods-glof/

https://forumias.com/blog/what-are-the-ndma-guidelines-for-glofs-related-disasters/

Source: Down to Earth ,  The Hindu

Gs3: Conservation, Environmental Pollution, and Degradation, Environmental Impact Assessment.

Synopsis: The recent Glacial outburst in Uttarakhand’s Chamoli district is a consequence of human’s impact on climate and lack of awareness towards local ecology.

Background

• Recently a glacier collapsed in Uttarakhand’s Nanda Devi. According to some satellite images, the glacier collapsed as a result of a landslide. It resulted in flash floods in the Rishiganga and Dhauliganga rivers.
• It claimed many lives of persons working in two hydropower projects.
• Although the ITBP through immediate action rescued nearly 15 people still many people are found missing.

How Climate change is impacting the Mountain ecosystem and how it is impacting Human livelihood?

1. Anthropogenic activities are continuously affecting the earth’s climate. The change in the Mountain ecosystem is an indicator of that effect.
2. Mountain ecosystems are highly vulnerable to climate change owing to their altitude, slope, and orientation to the sun.
3. Due to increased global warming, mountains glaciers are melting at unprecedented rates. It is reducing the area for the survival of flora and fauna.
   • For example, satellite observations reveal that across India, China, Nepal, and Bhutan the melting of glaciers has doubled since the start of the 21st century.
4. The melting of glaciers threatens water sustainability for hundreds of millions of people in counties, including India. These impacts become severe due to the increase in pressure on water resources for irrigation and food production, industrialization, and urbanization.

What are the reasons for climatic disaster in Uttarakhand?

The frequent disasters in Uttarakhand are not only caused by nature but also due to an indiscriminate increase in hydropower projects.

• Uttarakhand mountain ecosystem faces various threats such as seismicity, dam-induced micro seismicity, landslides. For example, the entire State of Uttarakhand falls under Zone-IV and V of the earthquake risk map of India.
• Besides being an earthquake-prone zone, it is also prone to Flood disasters. Bursting of glacial lakes can cause flash floods with catastrophic consequences. For instance, moderate earthquakes in the Tehri dam caused the 2013 floods in Kedarnath.
• Despite all these threats, the Uttarakhand government has indiscriminately pursued a greater number of hydropower projects. For example, the ongoing Tapovan power project.
• Also, India has heavily invested in dam development and the growth of hydropower in the Himalayas’ region to cut carbon emissions.
  • For example, if the national plan to construct dams in 28 river valleys in the hills is completed, the Indian Himalayas will have one dam for every 32 km. (The highest density in the world).
• Apart from this, the life of dams is often exaggerated without taking a proper account of the siltation level in the dams. For example, in the Bhakra dam in Himachal Pradesh, the siltation was higher by 140% than calculated.

These hydropower projects are incompatible with the local environment and ecology. They have increased the risk of disaster manifolds impacting the life and livelihood of millions of people.

What is the way forward?

• The government should realize that the fragility of the Himalayan mountain’s ecosystems. Governments need to re-prioritize their projects based on the potential of the mountains, local and traditional knowledge as well as the aspirations of the place.
• Hydro projects should be confined to the areas with the least impact in the Himalayas. Also, the government needs to build more low-impact run-of-the-river power projects rather than building destructive large dams and reservoirs.
• Projects that are incompatible with the local environment and ecology should not be promoted just by giving due consideration to development or economic growth.

What is the News?

NDMA has issued guidelines to reduce disasters related to Glacial Lake Outburst Floods (GLOFs). Recently GLOF is suspected to have caused the flash floods in Uttarakhand’s Chamoli.

What are Glacial Lake Outburst Floods(GLOFs)?

• It refers to the flooding that occurs when the water dammed by a glacier or a moraine is released suddenly.

 Click Here to Read Further on GLOFs

• According to National Disaster Management Authority (NDMA), Climate change is facilitating the glacial retreat in most parts of the Hindu Kush Himalayas. It is resulting in the formation of numerous new glacial lakes. Due to that, this area has become prone to GLOFs.

NDMA Guidelines for Reducing GLOFs:

The NDMA, headed by PM, had issued detailed guidelines on how to reduce and deal with disasters caused by GLOFs:

• Identify and Mapping Dangerous Lakes: Potentially dangerous lakes can be identified. This identification will be based on field observations, past events, geomorphologic and geotechnical characteristics, etc.
• Use of Technology: It has recommended the use of Synthetic-Aperture Radar imagery. It will automatically detect changes in water bodies, including new lake formations, during the monsoon months.
• Structural Measures: It recommends reducing the volume of water with various methods to manage lakes structurally. Methods are pumping or siphoning out water and making a tunnel through the moraine barrier or under an ice dam.
  • Example: In 2014, a landslide occurred along Phuktal (tributary to Zanskar river) in Kargil district of Ladakh. It led to a potential flood situation. The NDMA created an Expert Task Force which along with the Army used explosives to channel water from the river. It used controlled blasting and manual excavation of debris for this purpose.
• Constructions and development in High prone areas should be prohibited. It is a very efficient means to reduce risks at no cost.
• Land Use Planning: Land use planning regulations need to be developed. In downstream areas, Infra. development should be monitored prior to, during, and after the construction.
• Trained Local Manpower: Apart from specialized forces such as NDRF, ITBP, and the Army, there is a need for trained local manpower. These teams will assist in planning and setting up emergency shelters, distributing relief packages, identifying missing people, and addressing the needs for food, healthcare, water supply, etc.
• Early Warning System: A robust early warning system in vulnerable zones should be put in place.
• Emergency medical response team: Quick Reaction Medical Teams, mobile field hospitals, Accident Relief Medical Vans, and heli-ambulances should be set up in areas inaccessible by roads.
• Psychological Counselling: The guidelines also call for psychological counseling of victims.

Source: Indian Express

Pangong Tso Lake is an endorheic lake (landlocked) located in eastern Ladakh. It lies partly in India’s Ladakh region and partly in Tibet. The lake is formed from Tethys geosyncline.

• The lake literally translates into a “conclave lake”. Pangong means conclave in Ladakhi and Tso means a lake in the Tibetan language.
• The Karakoram Mountain range which crosses Tajikistan, Afghanistan, Pakistan, China and India ends at the north bank of Pangong Tso.
• The lake’s water is crystal clear, brackish making it undrinkable. The lake freezes during the winter allowing some vehicular movement on it as well.
• Who controls Pangong Tso?
  Nearly two-thirds of the lake is controlled by China with just about 45 km under Indian control. The Line of Actual Control(LAC) running north-south cuts the western part of the lake, aligned east-west.
• Importance of the lake:
  • The legendary 19th century Dogra general Zorawar Singh is said to have trained his soldiers and horses on the frozen Pangong lake before invading Tibet.
  • The north of the lake, lies Army’s Dhan Singh Thapa post, named after Major Dhan Singh Thapa
  • LAC(Line of Actual Control) mostly passes on the land, but Pangong Tso is a unique case where it passes through the water as well
  • The importance of the lake is due to the fact that it lies in the path of the Chushul approach of China. (China uses Chushul valley for performing offensive activities into Indian-held territory).
  • Over the years, the Chinese have built motorable roads along their banks of the Pangong Tso
  • In 1999, when the Army unit moved to Kargil for Operation Vijay, China took the opportunity to build 5 km of the road inside Indian territory along the lake’s bank. This is used by China for tactical advantage.

Additional Facts:

• Endorheic (Landlocked) Lake: It is a collection of water within an endorheic basin or sink, with no evident outlet. The Endorheic lakes are generally saline (unable to get rid of solutes left during evaporation).

Context: China’s major hydropower project as a part of its 14th Five-Year Plan (2021-25), on the Yarlung Zangbo River, in Mêdog County in Tibet.

More on news:

• The hydropower generation station is expected to provide 300 billion kWh of electricity annually. The Chinese authorities say the project will help the country realise its goal of reaching a carbon emission peak before 2030 and carbon neutrality before 2060.
• Indian counterparts were quick to restate their plans to dam the Himalayas on this side of the border. India is reportedly considering a 10-GW hydropower project in an eastern State.

What are the various misadventures that can happen due to the building of hydropower dams?

• Unavailability of dams: Both countries ignore how unviable such ‘super’ dams projects are, given that they are being planned in an area that is geologically unstable.
• Competing dams: Over the past 20 years, both China and India have been competing with each other to build hydroelectric dams in this ecologically fragile and seismically vulnerable area.
  • There are two hydropower projects in the works in Arunachal Pradesh on the tributaries of the Brahmaputra: the 600 MW Kameng project on the Bichom and Tenga Rivers and the 2,000 MW Subansiri Lower Hydroelectricity Project.
  • China has already completed 11 out of 55 projects that are planned for the Tibetan region.
• Overestimating economic potential: In executing these hydroelectric projects, the two countries have overestimated their economic potential and grossly underestimated the earthquake vulnerability of the region.
• Earthquakes in the region: High seismic zones coincide with areas of high population concentration in the Himalayan region where landslides and glacial lake outburst floods are common.
  • About 15% of the great earthquakes of the 20th century occurred in the Himalayan region. The northeast Himalayan bend has experienced several large earthquakes of magnitude 7 and above in the last 100 years, more than the share from other parts of the Himalayas.
  • The 2015 Gorkha earthquake of magnitude 7.8 in central Nepal resulted in huge losses in the hydropower sector. Nepal lost about 20% of its hydropower capacity consequent to the earthquake.
• Landslides: The main mechanisms that contributed to the vulnerability of hydropower projects were found to be landslides, which depend on the intensity of seismic ground shaking and slope gradients.
  • Heavy siltation from giant landslides expected in the project sites will severely reduce the water-holding capacity and life expectancy of such dams.
  • Even without earthquakes, the steep slopes made of soft rocks are bound to slide due to deforestation and road-building.

What can be done?

• Nature reserve: In recent years, the Himalayas have seen the highest rate of deforestation and land use changes. The upper Himalayas should be converted into a nature reserve by an international agreement.
• Himalayan river commission: The possibility of a Himalayan River Commission involving all the headwater and downstream countries needs to be explored.

Way forward

• India and China, the major players in the region, would be well advised to disengage from military adventurism and seek ways of transforming this ‘roof of the world’ into a natural reserve for the sake of humanity. Carbon neutrality should not be at the expense of the environment.