GS1 PYQ (Mains Answer Writing): Geomorphology | Geography for UPSC CSE PDF Download

Q1: Mention the global occurrence of volcanic eruptions in 2021 and their impact on Regional environment. (UPSC GS1 Mains )

Answer: 

A volcano eruption is when lava and gas are released from an active volcano, often explosively. Volcanoes have significant  impact on the regional environment, as can be seen from the examples of following volcanoes in 2021:

• Hunga Tonga-Hunga Hapai: The submarine volcano erupted in December, 2021.  
• Taal volcano: The volcano near Manila, experienced eruptions in 2021.  
• Nyiragongo: The violent/explosive eruption of this volcano in Democratic Republic of Congo affected the local population, as it killed dozens of people.  
• Iceland: The volcanic system of Iceland, erupted in 2021. It filled the valley with dark black lava for months before the eruption ceased.  
• La-Palma: The volcanic system in the canaries to saw eruption of an explosive volcano in 2021.

Impacts on  local environment:

• Plumes of volcanic ash can spread over the large areas of the sky, reducing visibility.  
• Volcanic eruptions are often accompanied with events of volcanic lightning.  
• Volcanic ash reflects incoming solar radiation leading to a localised cooling effect in the temperature.  For example, Mt. Krakatau brought mini ice age. 
• The volcanic ashes are known to increase the soil productivity of the region.  
• Carbon di oxide and fluorine gas can get collected in volcanic ash, and can pollute the regional environment, making it difficult for animals and humans to breathe. 
• Volcanic eruptions are also known to stimulate earthquakes in the region.

Volcanoes are a natural phenomenon. Most of the  active volcanoes are around the Pacific rim of fire. Though, volcanoes cannot be avoided, steps can be taken to mitigate their effects.

Q2: Describe the characteristics and types of primary rocks.(UPSC GS1 Mains Paper)

Answer: 

Understanding Igneous Rocks: Igneous rocks are termed as primary rocks as they are the initial ones to form in the rock cycle and don't contain any organic remnants. They originate from the cooling and solidifying of hot molten rock.

• Intrusive Igneous Rocks: These rocks develop when magma cools deep within the Earth, undergoing slow solidification over vast periods. This extended cooling allows mineral grains to grow large, resulting in a coarse texture. Examples include Diabase, Granite, Pegmatite, and Peridotite.

• Extrusive Igneous Rocks: Produced from magma that cools rapidly upon reaching or nearing the Earth's surface, these rocks form in volcanic eruptions. Immediate cooling results in a fine-grained or glassy texture. Often, these rocks exhibit trapped gas bubbles, creating a vesicular appearance. Examples are Basalt, Pumice, Obsidian, and Andesite.

Q3: Discuss about the vulnerability of India to earthquake related hazards. Give examples including the salient features of major disasters caused by earthquakes in different parts of India during the last three decades.  (UPSC GS1 Mains Paper)

Answer:

Understanding Earthquakes:
An earthquake occurs when the earth releases energy, generating waves that travel in all directions, leading to shaking and various hazards like ground shaking, surface rupture, landslides, and tsunamis.

Reasons for India's Earthquake Vulnerability:

• Tectonic Activity: India's movement into the Eurasian plate exposes it to moderate to very high-intensity earthquakes.

• Population Density and Unplanned Urbanization: Densely populated areas, unscientific constructions, and unplanned urban growth elevate risks.

• Himalayan Foothills: Vulnerability in these regions includes liquefaction and landslides triggered by earthquakes.

Significant Earthquake Disasters:

• 1993, Latur: Shallow depth led to substantial surface damage; causes remain debated due to lack of plate boundaries in the region.

• 1999, Chamoli: Thrust fault-induced disaster causing landslides, surface changes, and disconnected valleys.

• 2001, Bhuj: Associated with a reactivated fault, resulting in significant loss of life and property.

• 2004, Indian Ocean Tsunami: Underwater seismic activity leading to massive waves flooding coastal areas and causing long-term changes.

• 2005, Kashmir: Severe upthrust of Indian plate against Eurasian plate causing disruptions in infrastructure and communication.

Earthquake Safety in India:
India has made progress in earthquake safety, yet much more needs to be accomplished. Developing a system and culture for constructing safe houses is not just possible but an absolute necessity in 21st century India.