💥Join UPSC 2027,2028 Mentorship (August Batch) + XFactor Notes & Microthemes PDF
Talk to Mentor

Civilsdaily

Login

GS Paper: GS1-15.Geographical features and their location- Changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.

  • Big Island (Hawaii)

    Why in the news?

    A magnitude 6.0 earthquake struck near Honaunau-Napoopoo on the Big Island.

    About the Big Island

    • The largest island in the Hawaiian archipelago
    • Part of Hawaii in the Pacific Ocean
    • Area: ~10,432 km²
    • Formed through volcanic activity

    Five Major Volcanoes

    • Kohala
    • Hualālai
    • Mauna Kea
    • Mauna Loa
    • Kīlauea

    Important Volcanoes

    Mauna Loa

    • One of the world’s largest volcanoes
    • Shield volcano
    • Greatest mass of any mountain on Earth

    Kīlauea

    • Among the world’s most active volcanoes
    • Frequently erupting since 1983

    Shield Volcano

    • A volcano with broad, gentle slopes formed by fluid lava flows. Examples: Mauna Loa and Kīlauea

    Mauna Kea

    • The highest point in Hawaii above sea level
    • Hosts major astronomical observatories

    Hawaiʻi Volcanoes National Park

    • UNESCO World Heritage Site
    • Protects Kīlauea and Mauna Loa volcanoes

    Why are Earthquakes Common in Hawaii?

    Due to:

    • Volcanic activity
    • Movement of tectonic plates
    • Hotspot volcanism

    Hotspot Volcanism

    • A hotspot is a place where hot magma rises from Earth’s mantle. As the Pacific Plate moves over it, volcanic islands form.

    [2024] Consider the following:
    1. Pyroclastic debris
    2. Ash and dust
    3. Nitrogen compounds
    4. Sulphur compounds
    How many of the above are products of volcanic eruptions?

    [A] Only one

    [B] Only two

    [C] Only three

    [D] All four

  • AMOC Collapse and Its Impact on India 

    Why in the News

    Scientists have warned that the Atlantic Meridional Overturning Circulation (AMOC), a major Atlantic Ocean current system, could weaken drastically by 2100 due to climate change, potentially affecting global climate and the Indian monsoon.

    What is AMOC (Atlantic Meridional Overturning Circulation)?

    • A large system of ocean currents in the Atlantic Ocean often described as a global ocean conveyor belt

    How AMOC Works

    • Warm, salty surface water flows northward from the tropics
    • Near the Arctic, water cools and becomes denser
    • Dense water sinks deep into the ocean
    • Cold deep water then flows southward

    Importance of AMOC

    • Maintains relatively mild climate in Europe
    • Influences:
      • Rainfall patterns
      • Monsoons
      • Global temperature distribution
      • Marine ecosystems

    Connection with El Niño

    • El Niño
      • Periodic warming of Pacific Ocean waters
      • Influences global weather patterns
    • A weaker AMOC may: Make El Niño events more extreme and unpredictable
    [2020] With reference to Ocean Mean Temperature (OMT), which of the following statements is/are correct? 
    1.OMT is measured up to a depth of 26ºC isotherm which is 129 meters in the south-western Indian Ocean during January-March. 
    2.OMT collected during January-March can be used in assessing whether the amount of rainfall in monsoon will be less or more than a certain long-term mean. 
    Select the correct answer using the code given below: 
    a) 1 only b) 2 only c) Both 1 and 2 d) Neither 1 nor 2

  • Mayon Volcano 

    Why in the News

    The Mayon Volcano recently erupted, leading to the evacuation of thousands of people in affected areas of the Philippines.

    About Mayon Volcano

    • Type: Active stratovolcano (composite volcano)
    • Location: Albay province, Luzon Island
    • Height: 2,462 metres
    • Known as: “World’s most perfect volcanic cone” due to its symmetry

    Geographical Setting

    • Part of the Pacific Ring of Fire
    • Located near the Philippine Trench
    • Formed at a convergent plate boundary
      • Philippine Sea Plate subducting beneath the Philippine Mobile Belt

    What is a Stratovolcano

    • Tall, steep cone shaped volcano
    • Built from alternating layers of:
      • Lava
      • Pyroclastic material
    • Found mainly in subduction zones
    • Magma type:
      • Andesite and dacite (viscous lava)
    • Leads to explosive eruptions
    [2024] Consider the following: 
    1. Pyroclastic debris 
    2. Ash and dust 
    3. Nitrogen compounds 
    4. Sulphur compounds 
    How many of the above are products of volcanic eruptions? 
    [A] Only one [B] Only two [C] Only three [D] All four

  • Andaman Sea  

    Why in the News?

    • A boat carrying Rohingya refugees capsized in the Andaman Sea, highlighting its strategic and humanitarian importance.

    About the Andaman Sea

    What it is

    • A marginal sea of the northeastern Indian Ocean
    • Acts as a maritime link between:
      • South Asia
      • Southeast Asia

    Location

    • Lies between:
      • 4°N to 20°N latitude
      • 92°E to 100°E longitude

    Connected Water Bodies

    • West: Bay of Bengal
    • East: South China Sea (via Strait of Malacca)

    Boundaries

    • North: Irrawaddy delta (Myanmar)
    • East: Myanmar, Thailand, Malaysia
    • South: Indonesia (Sumatra)
    • West: Andaman & Nicobar Islands (India)

    Origin of Name

    • Derived from “Handuman” (Malay form of Hanuman)
    • Linked to ancient maritime trade and cultural exchanges
    [2020] Consider the following pairs: River – Flows into 
    1. Mekong — Andaman Sea 
    2. Thames — Irish Sea 
    3. Volga — Caspian Sea 
    4. Zambezi — Indian Ocean 
    Which of the pairs given above is/are correctly matched? 
    a) 1 and 2 only b) 3 only c) 3 and 4 only d) 1, 2 and 4 only

  • Satellite data show India’s major deltas sinking

    Why in the News

    A global study published in Nature on 14 January reports widespread land subsidence across India’s major river deltas, driven largely by human activities and observed using Sentinel 1 satellite data.

    Study at a Glance

    • Data source Interferometric Synthetic Aperture Radar from ESA Sentinel 1
    • Period 2014 to 2023
    • Coverage 40 major global deltas including 6 Indian deltas
    • Spatial resolution 75 metres
    • Population relevance Deltas support over 340 million people globally

    Indian Deltas Confirmed to be Sinking

    • Ganges Brahmaputra Delta, Brahmani Delta, Mahanadi Delta, Godavari Delta, Cauvery Delta and Kabani Delta.
    • More than 90 percent area affected in Ganges Brahmaputra, Brahmani and Mahanadi deltas.

    Key Quantitative Findings

    • Brahmani delta: 77 percent area sinking at more than 5 mm per year
    • Mahanadi delta: 69 percent area sinking at more than 5 mm per year
    • In Ganges, Brahmani, Mahanadi, Godavari and Kabani,
       Subsidence rate exceeds regional sea level rise
    • Godavari delta: Even 95th percentile subsidence exceeds projected global sea level rise under worst climate scenario
    • Kolkata: Subsidence equals or exceeds delta average due to urban load and resource extraction

    Major Human Drivers Identified

    • Unsustainable groundwater extraction: Ganges Brahmaputra and Cauvery deltas
    • Rapid urbanisation: Brahmani delta
    • Reduced sediment flux: Mahanadi and Kabani deltas
    • Population pressure: Intensifies compaction and land lowering
    [2018] Which of the following is/are the possible consequence/s of heavy sand mining in riverbeds? 

    1. Decreased salinity in the river 

    2. Pollution of groundwater 

    3. Lowering of the water-table 

    Select the correct answer using the code given below: 

    (a) 1 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2 and 3

  • Show Cause Notice on Bargi Dam 

    Why in the News?

    The National Dam Safety Authority issued a show cause notice to the Narmada Valley Development Authority over serious safety lapses at Bargi Dam.

    About Bargi Dam

    • A major multipurpose dam
    • Used for irrigation, drinking water supply, and hydroelectric power generation
    • Jabalpur district, Madhya Pradesh
    • Constructed on the Narmada River

    Historical Background

    • Built under the Narmada Valley Development Project
    • First completed major dam among the planned series on the Narmada in Madhya Pradesh
    • Became the foundation project for the state’s Narmada basin development strategy

    Key Features

    • 21 spillway gates: Regulate flood discharge and reservoir levels during heavy rainfall
    • Bargi Diversion Project: Canal network supplying irrigation to drought prone regions
    • Rani Avantibai Lodhi Sagar Project: Large scale storage and distribution system for irrigation and water supply
    • Large reservoir supporting: Drinking water, Hydropower, Fisheries and Tourism and recreation

    Significance

    • Provides drinking water to Jabalpur and nearby districts
    • Supports agriculture through assured irrigation
    • Contributes to electricity generation
    • Boosts regional development and eco tourism

    Institutional Context

    National Dam Safety Authority

    • Apex body under the Dam Safety Act 2021
    • Responsible for surveillance, inspection, and safety compliance of specified dams

    Narmada Valley Development Authority

    • Implements and manages projects under the Narmada basin
    • Responsible for operation and maintenance of dams like Bargi

    Prelims Pointers

    • Bargi Dam is on the Narmada River
    • Located in Madhya Pradesh
    • Part of the Narmada Valley Development Project
    • NDSA acts under the Dam Safety Act 2021
    • Spillway gates are crucial for flood control
    [2016] The Narmada river flows to the west, while most other large peninsular rivers flow to the east. Why? 

    1. It occupies a linear rift valley

    2. It flows between the Vindhyas and the Satpuras

    3. The land slopes to the west from Central India

    Select the correct answer using the codes given below

    (a) 1 only (b) 2 and 3 (c) 1 and 3 (d) None

  • Minamitori Island  

    Why in the News?

    Japan has decided to conduct test mining of rare earth rich mud from the deep seabed near Minamitori Island to reduce dependence on imported critical minerals.

    About Minamitori Island

    • Minamitori Island is also known as Marcus Island.
    • It is an isolated Japanese coral atoll located in the northwestern Pacific Ocean.
    • It marks the easternmost territorial point of Japan.
    • It is the first location in Japan to witness sunrise due to its eastern position.
    • The island is situated about 1,950 kilometres southeast of central Tokyo.

    Geographical and Geological Features

    • Minamitori Island represents the exposed summit of a massive underwater seamount.
    • The seamount rises from the deep ocean floor along the Marcus Necker Ridge.
    • It is the only landmass of Japan that lies entirely on the Pacific Plate.
    • The island provides Japan with a large Exclusive Economic Zone in the Pacific Ocean.

    What is Rare Earth Mud

    • Rare earth mud is a type of pelagic sediment formed from the accumulated remains of plankton.
    • Over millions of years, these sediments become enriched with rare earth elements.
    • The mud contains significant quantities of neodymium and dysprosium.
    • These elements are essential for manufacturing high performance permanent magnets.
    Consider the following statements: (2021)

    1. The Global Ocean Commission grants licenses for seabed exploration and mining in international waters. 

    2. India has received licenses for seabed mineral exploration in international waters. 

    3. ‘Rare earth minerals’ are present on the seafloor in international waters. 

    Which of the statements given above are correct? 

    (a) 1 and 2 only (b) 2 and 3 only (c) 1 and 3 only (d) 1, 2, and 3

  • Chillai Kalan Begins in Kashmir 

    Why in the News?

    The higher reaches of Kashmir Valley witnessed snowfall and the plains received rain as Chillai-Kalan, the harshest 40 day winter phase, began on December 21, 2025.

    What is Chillai Kalan

    • Meaning: Big cold in Kashmiri
    • Duration: 40 days
    • Period: December 21 to January 30
    • Significance: Coldest phase of winter in Kashmir
    • Belief: Rain or snow on the first day is considered a good omen and indicates heavy snowfall ahead

    Importance of the Precipitation

    • Ended a prolonged dry spell in the Valley
    • Helped reduce dust and dryness
    • Expected to improve water availability and snow reserves
    • Dry winter last year had caused
      • Health issues like cough and cold
      • Problems for agriculture and tourism sector

    Follow-Up Cold Phases

    After Chillai Kalan, Kashmir experiences two shorter cold spells

    • Chillai Khurd meaning small cold
    • Chillai Bacha meaning baby cold

    Prelims Pointers

    • Chillai Kalan is unique to Kashmir climate tradition
    • Heavy snowfall during this phase replenishes glaciers and water sources
    • Gulmarg and Sonamarg are key winter tourism centres
    • Sadhna Top is strategically important due to its proximity to the Line of Control
    [2015] Consider the following statements: 

    1. The winds which blow between 30° N and 60° S latitudes throughout the year are known as westerlies. 

    2. The moist air masses that cause winter rains in North-Western region of India are part of westerlies. 

    Which of the statements given above is/are correct? 

    (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2

  • Kavachi Volcano

    Why in the News?

    Scientists have reported rare underwater footage showing sharks living inside the crater of Kavachi volcano, near the Solomon Islands. This discovery challenges earlier assumptions about marine survival in extreme volcanic environments.

    About Kavachi Volcano

    • A shallow submarine volcano located in the South Pacific Ocean
    • Situated south of Vangunu Island in the Solomon Islands
    • Lies on the Pacific Ring of Fire, a highly tectonically active zone
    • Among the few active and visible undersea volcanoes in the world

    Volcanic Activity

    • Known for frequent but unpredictable eruptions
    • First documented eruptive activity in 1939
    • Has experienced multiple temporary island forming events

    Prelims Pointers

    • Type: Submarine volcano
    • Location: South Pacific Ocean
    • Tectonic setting: Pacific Ring of Fire
    • Key feature: Temporary island formation
    • Recent relevance: Sharks observed inside a volcanic crater

    [2024] Consider the following: 1. Pyroclastic debris 2. Ash and dust 3. Nitrogen compounds 4. Sulphur compounds. How many of the above are products of volcanic eruptions? 

    (a) Only one

    (b) Only two

    (c) Only three

    (d) All four 

  • Hormuz Island

    Why in the News?

    • A rare natural phenomenon turned the coastlines of Hormuz Island into a blood red landscape, drawing global attention

    About Hormuz Island

    • Location: Iran, on the Strait of Hormuz
     • Lies between the Persian Gulf and the Gulf of Oman
     • Situated about 8 km off the Iranian coast
     • Area: 41.9 sq km
     • A hilly island with distinctive geomorphology

    Geological Features

    • Composed mainly of sedimentary rocks and volcanic ash
     • Dominant red colour due to high iron oxide content
     • Presence of hematite mineral gives the soil its deep red hue
     • Ocean waves turn pink when they wash over iron rich sands

    Soil and Climate

    • Experiences low precipitation
     • Soil and water are saline in nature
     • Landscape is largely barren

    Unique Identity

    • Known as Rainbow Island due to multi coloured soil
     • Sand and soil colours include red, gold, silver, and white

    Human Settlement and Livelihood

    • Hormuz village is the only permanent settlement
     • Fishing is the primary source of livelihood
     • Inhabited mainly by the Bandari ethnic group

    What is the importance of developing Chabahar Port by India? (2017)

    (a) India’s trade with African countries will enormously increase. 

    (b) India’s relations with oil-producing Arab countries will be strengthened. 

    (c) India will not depend on Pakistan for access to Afghanistan and Central Asia. 

    (d) Pakistan will facilitate and protect the installation of a gas pipeline between Iraq and India.