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Subject: Geographical Features

  • Volcanic Eruption in Ethiopia and Impact on India

    Why in the news?

    The Hayli Gubbi volcano in Ethiopia’s Afar region erupted on 23 November 2025 after nearly 12,000 years of dormancy, producing a massive ash plume rising to ~14 km (45,000 ft). High-level winds transported volcanic ash across the Red Sea and Arabian Peninsula towards western and northern India, causing temporary disruption in aviation operations.

    Key Facts: Location & Geological Background 

    Hayli Gubbi Volcano

    • Type: Shield volcano
    • Location: Afar Region, Ethiopia (part of the East African Rift System)
    • Dormancy: Last known activity ~10,000–12,000 years ago (Holocene threshold)
    • Geological Setting: Lies on the triple junction where the Arabian, Nubian, and Somali plates are diverging → high tectonic activity.

    East African Rift System (EARS)

    • A major continental rift zone.
    • Known for active volcanism (Erta Ale, Dabbahu, Nabro, etc.).
    • Possible future site of a new ocean basin due to plate divergence.

    Impact on India

    1. Flight Disruptions

    • Several international flights cancelled or delayed (Delhi, Mumbai, Hyderabad, Kochi).
    • Airlines: Air India, IndiGo, Akasa Air initiated precautionary measures.
    • Aircraft inspections ordered for those that flew through potentially affected air corridors.

    2. Airspace Management

    • Civil Aviation Ministry, Air Traffic Control (ATC), and the India Meteorological Department (IMD) issued continuous advisories.\
    • No major safety threat, but routing adjustments and cancellations made as precaution.

    3. No Impact on Local Weather or Air Quality

    • IMD clarified:
      • Ash remained in upper troposphere.
      • No impact on ground-level AQI.
      • Delhi’s poor air quality is unrelated, caused by local pollution.

    4. Clearance Timeline

    • Ash plume expected to move completely towards China by 7:30 pm, Nov 25.

    Why Aviation Avoids Volcanic Ash? 

    • Ash melts inside jet engines → forms glassy deposits → engine flameout.
    • Damages navigation systems & windshields.
    • Reduces visibility.
    • Can cause stalls, loss of thrust, and total engine failure.

    Relevant Organisation:
    Volcanic Ash Advisory Centers (VAACs) issue global alerts—here, Toulouse VAAC monitored the plume.

    Consider the following: (2024)

    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) Only four

  • Low-Pressure Area in Bay of Bengal (November 2025) 

    Why in the news?

    According to the India Meteorological Department (IMD), a low-pressure area formed over the Bay of Bengal on November 22, 2025. It is expected to intensify into a depression by November 24 and move west-northwestwards.

    What Has the IMD Reported?  

    a) Formation: Low-pressure area formed near the Malacca Strait over the South Andaman Sea. It arose due to a cyclonic circulation.

    b) Likely Path: Expected to move west-northwestwards. Likely to intensify into a depression over southeast Bay of Bengal & adjoining south Andaman Sea by November 24.

    c) Further IntensificationCould intensify further over the southwest Bay of Bengal within 48 hours after formation. IMD is uncertain whether it will develop into a cyclonic storm.

    d) State Impact (Odisha & Coastal Areas): System is far from Odisha coastdry weather Farmers in coastal and southern regions have started harvesting mature paddy in anticipation of possible heavy rains. The State Agriculture Department has not yet issued advisories.

    (2015) In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason? 

    (a) Sea surface temperatures are low 

    (b) Inter-Tropical Convergence Zone seldom occurs 

    (c) Coriolis force is too weak 

    (d) Absence of land in those regions

  • Sakurajima Volcano erupts in Japan’s Kyushu

    Why in the News?

    Japan’s Sakurajima volcano has erupted several times sending ash plumes up to 4.4 km into the atmosphere.

    Sakurajima Volcano erupts in Japan's Kyushu

    About Sakurajima Volcano:

    • Location: Kagoshima Prefecture, Kyushu, sitting on the southern rim of the Aira caldera inside Kagoshima Bay.
    • Geological Origin: Linked to formation of the Aira caldera (22,000–29,000 years ago); Sakurajima developed as a post-caldera cone about 13,000 years ago.
    • Volcano Type: A classic stratovolcano built from alternating lava and ash layers; active vents include Minamidake crater and the Showa flank crater.
    • Physical Features: Height 1,117 m, circumference ≈50 km; originally an island until 1914 lava flows connected it to the Osumi Peninsula.
    • Eruption Style: Dominantly Strombolian eruptions (ash, bombs, lapilli) but historically capable of large Plinian eruptions.
    • Historical Activity: Continuous eruptive record since 963 AD; major episodes in 1471–76, 1779–82, and the 1914 catastrophic eruption.
    • Risk Status: Considered one of Japan’s most dangerous volcanoes due to high activity, caldera-linked magma supply and extreme proximity to inhabited zones.

    What makes it unique?

    • Near-Continuous Activity: Erupts hundreds of times annually, ranking among the world’s most persistently active volcanoes.
    • Caldera System: Built on the Aira caldera, giving it a deep, complex, highly active magma plumbing network.
    • Landform Transformation: The 1914 eruption converted Sakurajima from an island into a peninsula, an unusual event in recorded volcanology.
    [UPSC 2005] Where is the volcanic mountain, Mount St- Helens located?

    Options: (a) Chile (b) Japan (c) Philippines (d) United States of America*

     

  • Floods force closure of Bhavani Island

    Why in the News?

    Flood discharges at Prakasam Barrage on the Krishna River has led to the closure of Bhavani Island from the mainland.

    About Bhavani Island:

    • Location: Situated on the Krishna River, near Vijayawada, Andhra Pradesh.
    • Area: Spans ~133 acres, among India’s largest river islands.
    • Management: Operated by the Andhra Pradesh Tourism Department as a major eco-tourism and recreational hub.
    • Accessibility: Lies upstream of Prakasam Barrage, connected only by ferry services from the mainland.
    • Ecology & Features: Rich in greenery, ponds, and meadows, offering boating, gardens, adventure parks, rural museums, and event spaces.
    • Cultural Link: Named after Goddess Bhavani (Kanaka Durga); her temple atop Indrakeeladri Hill overlooks the river.

    Krishna River

    Floods force closure of Bhavani Island

    • Overview: One of India’s major peninsular rivers, stretching about 1,400 km.
    • Origin & Course: Rises near Mahabaleshwar (Maharashtra), flows eastward through Karnataka, Telangana, and Andhra Pradesh, entering the Bay of Bengal at Hamsaladeevi.
    • Basin Extent: Covers ~2.59 lakh sq km, nearly 8% of India’s area.
    • Boundaries: Flanked by Balaghat Range (north), Eastern Ghats (east), and Western Ghats (west).
    • Tributaries:
      • Right Bank: Ghataprabha, Malaprabha, Tungabhadra, and Musi Rivers.
      • Left Bank: Bhima, Koyna, Yerla, Panchganga, and Dudhganga Rivers.
    • Projects & Dams: Major hydropower and irrigation structures including Almatti, Srisailam, Nagarjuna Sagar, Narayanpur, and Jurala.
    • Prakasam Barrage: Built near Vijayawada to regulate water flow, support irrigation, navigation, and tourism.
    • Economic Role: Sustains agriculture, fisheries, and power generation, forming the riverine backbone of southern India.
  • [29th October 2025] The Hindu OpED: Relief, Rehabilitation: India’s east coast and cyclones

    PYQ Relevance

    [UPSC 2014] Tropical cyclones are largely confined to the South China Sea, Bay of Bengal and Gulf of Mexico. Why?

    Linkage: Cyclones are a recurring topic in GS Paper 1 (Geography) and GS Paper 3 (Disaster Management) due to their climatic, socio-economic, and governance relevance. The PYQ links directly to this theme as it explains the geophysical reasons behind the east coast’s high cyclone frequency and sets the context for India’s preparedness and rehabilitation strategies.

    Mentor’s Comment

    The recurring cyclones on India’s eastern coast highlight not only the country’s growing vulnerability to extreme weather events but also the evolution of its disaster management framework. The recent Cyclone Montha once again tested India’s readiness, reflecting both commendable progress and continuing challenges in disaster response, livelihood security, and post-disaster rehabilitation.

    Why in the News

    Cyclone Montha, which began intensifying into a severe cyclonic storm over the Bay of Bengal on October 27-28, 2025, has revived memories of devastating cyclones such as the 1977 Andhra cyclone and the 1999 Odisha super cyclone, each claiming nearly 10,000 lives. Although Montha was not as intense, it tested disaster preparedness mechanisms across Andhra Pradesh and Odisha. The event underlines both improved resilience and the persisting socio-economic costs of cyclones in India’s coastal belt, a region that historically faces the brunt of Bay of Bengal storms during October-November.

    Introduction

    India’s eastern coastline, especially Odisha and Andhra Pradesh, has long been vulnerable to tropical cyclones. Historically, the Bay of Bengal has produced some of the world’s deadliest cyclonic events. While the India Meteorological Department (IMD) and National Disaster Response Force (NDRF) have strengthened forecasting and evacuation systems, the scale of livelihood disruption, property damage, and rural distress continues to make post-cyclone rehabilitation a critical governance concern.

    Why is India’s East Coast So Vulnerable to Cyclones?

    1. Geographical Exposure: The Bay of Bengal’s funnel shape and warm waters create conditions for cyclogenesis, making the east coast more cyclone-prone than the west.
    2. Seasonal Concentration: Historically, October-November are peak months, with nine of twelve major cyclones (18th-20th century) recorded during this period.
    3. High Human Impact: The 1977 Andhra and 1999 Odisha cyclones each caused ~10,000 deaths, highlighting the historic vulnerability.

    How Prepared Are India’s Coastal States Today?

    1. Institutional Mechanisms: Strengthened Union and State disaster management authorities and IMD’s early warning systems have made large-scale loss of life “a thing of the past.”
    2. Evacuation Efficiency: Nearly 10,000 people evacuated from Andhra’s Kakinada and Konaseema during Cyclone Montha.
    3. Red Alert Response: Prompt deployment of NDRF teams and coordinated district-level action in red-alert zones of southern Odisha.

    What Are the Persisting Gaps and Challenges?

    1. Property and Livelihood Loss: Even with reduced fatalities, damage to homes, livestock, and agriculture remains high, affecting underprivileged sections.
    2. Economic Vulnerability: Cyclones disrupt milch animals, draught animals, and poultry, impacting rural incomes and food security.
    3. Infrastructure Fragility: Despite improvements, coastal roads, electricity grids, and communication lines remain highly exposed to storm surges and floods.

    What Has Been Learnt from Past Disasters?

    1. Adaptive Governance: Following disasters like Cyclone Gaja (2018), governments have adopted structural and non-structural mitigation measures, including cyclone shelters, embankments, and mangrove restoration.
    2. Skill Enhancement: Continuous upgrading of disaster management knowledge and coordination among states such as Andhra Pradesh, Odisha, and Tamil Nadu.
    3. Community Engagement: Enhanced public awareness and local volunteer networks contribute to faster evacuations.

    What Should Be the Way Forward for Relief and Rehabilitation?

    1. Holistic Recovery Approach: Combine immediate relief with long-term livelihood restoration and climate-resilient infrastructure.
    2. Inclusive Policy Execution: Focus on the most vulnerable coastal communities, particularly fishers and small farmers.
    3. Leadership Accountability: Political and administrative leadership must ensure effective implementation of rehabilitation and reconstruction measures post-disaster.

    Conclusion

    India’s eastern coastline remains a climatic frontier where human resilience is tested year after year. The evolution from reactive relief to proactive risk reduction marks a significant policy success. Yet, the persistence of livelihood loss and infrastructure fragility calls for stronger implementation, community engagement, and leadership accountability. Relief and rehabilitation must now evolve into a model of climate-adaptive, inclusive coastal development.

  • Taftan Volcano, Iran 

    Why in the News?

    New satellite data in Geophysical Research Letters (October 2025) shows Iran’s Taftan volcano, dormant for 710,000 years, is reactivating.

    Taftan Volcano, Iran 

    About Taftan Volcano:

    • Location: Situated in southeastern Iran, about 56 km from the Pakistan border, within the Makran continental volcanic arc.
    • Elevation: Rises to 3,940 metres (12,927 feet), Iran’s only active volcano in the Makran arc.
    • Tectonic Origin: Formed by subduction of the Arabian oceanic plate beneath the Eurasian continental plate.
    • Volcanic Type & Composition: A stratovolcano composed mainly of andesitic and dacitic lava, with pyroclastic flows and volcanic breccias.
    • Structure: Features two summits, Narkuh and Matherkuh, and extensive ignimbrite and lava fans stretching over 30 km.
    • Hydrothermal Activity: Hosts sulfur-emitting fumaroles, visible from up to 100 km, sustained by an active hydrothermal system.
    • Eruptive History: Major activity phases around 8 Ma, 6 Ma, and 0.7 Ma; last lava flow dated to about 6,950 years ago.
    • Recent Observations: 2023–24 satellite data detected 9 cm ground uplift, indicating subsurface pressure buildup and reclassification from extinct to dormant.

    Scientific Interpretation and Outlook:

    • Magma Dynamics: Uplift linked to gas accumulation or shallow magma intrusion at 490–630 m depth, possibly fed by deeper chambers (~3.5 km).
    • Current Status: No imminent eruption expected; likely pressure release via degassing or minor eruptions.
    • Monitoring Gap: Lack of ground-based GPS or seismic sensors; reliance on satellite InSAR data for deformation tracking.
    • Scientific Recommendations: Call for establishing a volcano observatory in southeastern Iran for real-time monitoring and gas analysis.
    • Regional Significance: Highlights Makran arc tectonic activity and underscores the need for international geophysical collaboration.
    • Research Importance: Taftan’s reawakening demonstrates the role of remote sensing in detecting hidden volcanic unrest and stresses continuous monitoring to assess eruption potential and regional hazard mitigation.
    [UPSC 2024] Consider the following:
    1. Pyroclastic debris 2. Ash and dust 3. Nitrogen compounds 4. Sulphur compoundsHow many of the above are products of volcanic eruptions?Options: (a) Only one (b) Only two (c) Only three (d) only four*

     

  • Delhi Morphological Ridge

    Why in the News?

    The Delhi government has decided to declare 41 sq. km of the Southern Ridge as a reserved forest under the Indian Forest Act, 1927, following long-pending directions from the National Green Tribunal (NGT).

    Delhi Morphological Ridge

    About Delhi Morphological Ridge:

    • The Delhi Ridge is the northern extension of the ancient Aravalli Range, stretching approximately 35 km from Tughlaqabad to Wazirabad, along the Yamuna River.
    • It is composed mainly of quartzite rock, is over 1.5 billion years old, and significantly older than the Himalayas.
    • It functions as Delhi’s green lungs, aiding in carbon sequestration, temperature regulation, and air pollution reduction.
    • It acts as a natural barrier against desert winds from Rajasthan and supports rich biodiversity, making Delhi one of the world’s most bird-rich capitals.
    • It is divided into four zones: Northern Ridge, Central Ridge, South-Central Ridge, and Southern Ridge.
    • Key conservation areas include the Northern Ridge Biodiversity Park and the Asola Bhatti Wildlife Sanctuary.

    Land Use Regulation in the Ridge:

    • Although the area shares ecological features with the Delhi Ridge, it is NOT officially notified as forest land, but it enjoys judicial protection.
    • A 1966 directive prohibits any NON-forest use or encroachment without court approval.
    • Any change in land use must be cleared by the Ridge Management Board (RMB) and the Supreme Court-appointed Central Empowered Committee (CEC).
    • The area is mapped using data from the Delhi Forest Department and the 2006 Seismic Zonation Map.
    • Formal notification as a Reserved Forest under the Indian Forest Act, 1927, is pending due to the absence of ground-truthing.
    • In revenue records, it is often marked as “gair mumkin pahad”, meaning uncultivable rocky hill.
    • The terrain is ecologically fragile, with shallow soil and rocky outcrops, making it unsuitable for construction.
    [UPSC 2001] The approximate age of the Aravalli range is-

    Options: (a) 370 million years (b) 470 million years (c) 570 million years (d) 670 million years

     

  • Volga River

    Why in the News?

    This newscard is an excerpt from the original article published in the Indian Express.

    Volga River

    About the Volga River:

    • Overview: The longest river in Europe (about 3,500 km), originating in the Valdai Hills northwest of Moscow and flowing southeast to the Caspian Sea at Astrakhan.
    • Drainage Basin: Covers around 1.35 million sq. km, among Europe’s largest river systems, with major tributaries, Kama, Oka, Vetluga, and Sura.
    • Historical Role: Served as a critical front during the Battle of Stalingrad (World War II) and remains central to Russian historical and strategic narratives.
    • Cultural Significance: Revered as “Mother Volga”, symbolising Russian unity, resilience, and identity, deeply embedded in folklore and national consciousness.
    • Economic Importance: It contributes one-fourth of Russia’s agricultural output, supports industrial fishing, and sustains key industries, oil refining, shipbuilding, hydroelectric power.
    • Navigation & Connectivity: Linked to the Baltic, Black, and Caspian Seas through an extensive network of canals and reservoirs, forming the backbone of Russia’s inland transport system.
    • Urban & Industrial Corridor: Major cities like Kazan, Samara, Nizhny Novgorod, and Volgograd lie along its course, forming Russia’s industrial-agricultural heartland.
    • Ecological Richness: Supports about 260 bird species and 70 fish species, making it a key biodiversity hotspot within Eurasia.
    [UPSC 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?

    Options: (a) 1 and 2 only (b) 3 only (c) 3 and 4 only * (d) 1, 2 and 4 only

     

  • India’s only Mud Volcano erupts after 20-years in Andamans

    Why in the News?

    India’s only mud volcano at Baratang Island in the Andaman and Nicobar Islands erupted after remaining dormant for over two decades.

    India's only Mud Volcano erupts after 20-years in Andamans

    Note: The Barren Island has erupted recently.

    • India’s only active lava volcano, located about 140 km from Port Blair.
    • Lies at the junction of the Indian and Burmese tectonic plates.
    • Eruption history: 1787 (first recorded), followed by episodes in 1991, 2005, 2017, November 2022, and September 2025.

    About the Baratang Mud Volcano:

    • Location: Baratang Island, around 100–150 km north of Port Blair, situated in the North and Middle Andaman district.
    • Uniqueness: It is India’s only collection of mud volcanoes — 11 in total across the archipelago, 8 of which are on Baratang and Middle Andaman.
    • Eruptions: Significant eruptions were last reported in 2005; the 2025 eruption marks the first major event in 20 years.
    • Composition & Nature:
      • Emits cool mud, water, and gases (methane, hydrogen sulfide) rather than lava or fire.
      • Creates mud cones, bubbling pools, or dried crater-like formations.
      • Eruptions are low in intensity, involving slow oozing and gas bubbling rather than violent explosions.
    • Accessibility: A short 160-metre walk from the nearest road; the site lies near the Jarawa Tribal Reserve, where photography is prohibited for ethical and legal reasons.

    Geological Formation and Features:

    • Tectonic Setting: Formed due to subduction of the Indian Plate beneath the Burmese Plate, leading to gas and fluid release from deep layers.
    • Mechanism:
      • Decomposition of organic matter underground produces gas pressure that pushes mud upwards.
      • These gases, along with water and sediments, escape to the surface, creating muddy eruptions and bubbling vents.
    • Temperature & Composition:
      • The expelled material is cool, unlike magmatic volcanoes.
      • Contains saline water, organic sediments, and gases, giving it a distinctive odour and appearance.
    • Earth Processes: The phenomenon helps scientists study fluid migration, methane emissions, and crustal deformation in active subduction zones.
    [UPSC 2018] Consider the following statements:

    1.The Barren Island volcano is an active volcano located in the Indian territory.

    2.Barren Island lies about 140 km east of Great Nicobar.

    3.The last time the Barren Island volcano erupted was in 1991 and it has remained inactive since then.

    Which of the statements given above is/are correct?

    Options: (a) 1 only * (b) 2 and 3 (c) 3 only (d) 1 and 3