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Subject: Geography

  • Sympathetic Solar Flares

    Why in the news?

    A rare celestial event unfolded as four solar flares called as Sympathetic Solar Flares simultaneously, signaling the onset of the Sun’s dynamic 11-year solar cycle.

    What is a Solar Cycle?

    • Given the Sun’s dynamic nature, electrically charged gases on its surface generate powerful magnetic fields, known as magnetic fields.
    • These magnetic fields undergo stretching, twisting, and tangling due to the constant movement of gases on the Sun’s surface, resulting in solar activity.
    • Scientists monitor solar cycles using sunspots. Solar activity fluctuates throughout the solar cycle, which typically spans about 11 years. 
    • The onset of a solar cycle typically features minimal sunspot activity, termed as a solar minimum.
    • For instance, the last Solar Cycle 25 commenced in December 2019, characterized by a low number of sunspots.

    What are Sympathetic Solar Flares?

    • Sympathetic solar flares are solar eruptions that occur in close temporal and spatial proximity to another solar flare or eruption.
    • These events are believed to be interconnected through magnetic fields or other physical processes occurring on the Sun.
    • When a solar flare or eruption happens on the Sun, it releases a burst of electromagnetic radiation and charged particles into space.
    • In some cases, the energy released during these events can cause disturbances in the Sun’s magnetic field.
    • These disturbances can trigger the occurrence of additional flares loop or eruptions in nearby regions of the Sun’s surface.
    • This event follows coronal mass ejections (CMEs) and intense plasma bursts.

    Implications for Earth

    • Potential impacts include disruptions to power grids, interference with communication networks, and increased radiation exposure for astronauts and aircraft passengers.
    • Solar storms can lead to spectacular natural light shows known as auroras, which are typically visible near the Earth’s magnetic poles.

    PYQ:

    [2012] The increasing amount of carbon dioxide in the air is slowly raising the temperature of the atmosphere, because it absorbs:

    (a) the water vapour of the air and retains its heat

    (b) the ultraviolet part of the solar radiation

    (c) all the solar radiations

    (d) the infrared part of the solar radiation
  • PREMIUM – Travelling the Regions of South America

    PREMIUM – Travelling the Regions of South America

    Why in the News?

    South America, known for its diverse landscapes and cultures, also harbors several disputed territories, each with its own historical, geopolitical, and economic significance. These disputes often arise from conflicting territorial claims, historical grievances, or resource-rich areas. 

    Diverse Landscapes of South America:

    • The Pacific Coastal Strip:
      • Between the ocean and the Andes mountain Range.
      • The coastline of South America is smooth and regular. At the river mouths, some inlets are used as harbors. The southwestern coast of the continent has fiords or deep inlets of the sea.
    • Andes Mountain Range:
      • The Andes stretch through the entire continent, running in the north-south direction from the Isthmus of Panama to the Strait of Magellan. The second-highest mountain system in the world.
      • Mount Aconcagua (an extinct volcano lies in Argentina)
      • Mount Ojas del Salado is the highest active volcano in the world of Argentina.
      • Part of seven countries: Venezuela, Colombia, Ecuador, Bolivia, Peru, Chile, and Argentina.
      • They form a chain of ranges and knots with enclosed intermontane plateaus namely in Ecuador and Bolivia.
      • Being part of the Pacific Ring of Fire, there are many volcanoes and frequent earthquakes in this region. Mount Cotopaxi and Mount Chimborazo are active volcanic peaks, which is the highest peak in South America.
    • About the Amazon River:
      • It is the world’s largest and second-longest (6,400 km) river in the world after the Nile.
      • Its journey begins high in the Andes Mountains. The river then makes its way east through thousands of miles of rainforests and lowlands until it empties into the Atlantic Ocean on the northeastern coast of Brazil
      • Its watershed spans the countries of Brazil, Peru, Ecuador, Colombia, Venezuela, and Bolivia.
      • It has more than 1,100 tributaries, which include the rivers like the Rio Negro, the Madeira River, and the Xingu River, etc.
      • The Amazon Rainforest, which represents about half of the Earth’s remaining rainforest, also constitutes its single largest reserve of biological resources.
      • It is sometimes referred to as the “lungs of the Earth” due to its role in regulating the planet’s oxygen and carbon cycles.

    Disputed Areas in South America

    Countries Involved Key Points Geographical Features
    Gulf of Venezuela Colombia, Venezuela
    • Inlet of the Caribbean Sea is Disputed over islands such as Los Monjes Archipelago due to Fishing rights and potential oil reserves.
    • Interpretation disputes regarding the 1941 Treaty of Delimitation            
    • Recent tensions over maritime confrontations and oil exploration activities.
    		 Surrounded by coastal mountain ranges with waters fed by several rivers
    Essequibo Region Guyana, Venezuela
    • Covers two-thirds of Guyana’s territory Historical grievances claimed by Venezuela.         
    • Recent oil discoveries raising tensions; ICJ case filed by Guyana.
    • Essequibo River flows through this region.
    		 Diverse landscapes including rainforests, savannahs, and mountains with the Essequibo River
    Atacama Desert Peru, Chile
    • Extremely Arid desert region            
    • War of the Pacific led to Chile’s control           
    • Valuable mineral resources contribute to disputes            
    • Bilateral talks and arbitration proposals for settlement
    		 Bordered by the Andes Mountains and the Pacific Ocean with salt flats, sand dunes, and volcanic formations
    Falkland Islands (Malvinas) Argentina, UK
    • Sovereignty disputes since 1833           
    • Economic interests include fisheries, tourism, and potential oil reserves           
    • Diplomatic efforts and UN resolutions for resolution
    		 Consists of two main islands with rugged coastlines and low mountains
    Darien Gap Colombia, Panama
    • Dense jungle terrain separating North and South America            
    • Challenges in illegal immigration discussions            
    • Characterized by dense rainforests, swamps, and mountains
    		 Part of the Darien National Park with dense rainforests, mangroves, and steep mountain slopes
    Arroyo de la Invernada or Rincon de Artigas… Brazil, Uruguay
    • Dispute over the Invernada River region near Masoller            
    • UN does not officially recognize the claim            
    • 237 km2 region with significant natural resources            
    • Efforts to resolve through bilateral talks and international mediation
    		 Rolling hills, grasslands, and small rivers with the Invernada River
    New River Triangle (Tigri Area) Suriname, Guyana
    • Disputed region within the Guiana Highlands            
    • Conflicting claims over territory interpretation of historical treaties and boundaries
    		 Dense rainforests, mountain ranges, and numerous rivers
    Isla Brasilera/Ilha Brasileira Brazil, Uruguay
    • Uruguay claims ownership of Isla Brasilera            
    • Strategically located near the tripoint with Argentina            
    • Efforts to resolve through diplomatic negotiations and legal arguments
    		 Small island located in the Uruguay River with lush vegetation
    Isla Suarez/Ilha de Guajara-mirim Bolivia, Brazil
    • Located in the Rio Mamore as a border between Bolivia and Brazil           
    • Economically dependent on Guajara-Mirim, Brazil            
    • Treaty signed in 1958 maintains the status quo            
    • Challenges of border management in riverine environments
    		 Riverine island characterized by tropical vegetation and wetlands
    Southern Patagonian Ice Field Argentina, Chile
    • Spanning parts of Argentina and Chile            
    • Border demarcation remains undefined in certain areas           
    • Bilateral efforts for resolution include scientific cooperation and mapping projects
    		 Vast expanse of ice and snow covering rugged mountain ranges and deep valleys
    Lithium Triangle  Argentina, Bolivia, and Chile
    • It is characterized by various salt pans or salars, concentrated along the Atacama Desert and adjacent arid regions.
    • The Salar de Atacama in Chile boasts the highest lithium concentration (0.15% by weight) among all brine sources worldwide. 
    • Argentina boasts more than half of the world’s total lithium resources and holds the distinction of having the 2nd-largest lithium resources, the 3rd-largest lithium reserves, and the 4th-largest lithium production in the world.
    • India’s KABIL (Khanij Bidesh India Ltd) has announced an investment of ₹211 crore ($25.712 million) over five years for exploration stage activities in five lithium blocks in the Fiambala area of Argentina.
    		 Key reserves of Lithium include:

    1. Uyuni (Bolivia): This salt flat is not only the world’s largest salt flat but also contains significant lithium reserves.  
    2. Atacama (Chile): Located in the Atacama Desert, Salar de Atacama is home to one of the largest lithium reserves globally. 
    3. Hombre Muerto (Argentina): This salt flat in northwestern Argentina also hosts lithium extraction operations.

     

    Note: Bolivia and Paraguay are land-locked countries in South America

    PYQ:

    [2013] “Climate is extreme, rainfall is scanty and the people used to be nomadic herders.”  

    The above statement best describes which of the following regions?

    (a) African Savannah

    (b) Central Asian Steppe

    (c) South American Tropical

    (d) Siberian Tundra

     

  • A lesson from Taiwan in quake resilience

    Why in the news? 

    On April 3, Taiwan was struck by an earthquake of 7.4 magnitude. This was strongest in last 25 years.

    Reason behind the earthquake in Taiwan

    • In the Taiwan region, the Philippine Sea plate is moving northwest towards the Eurasian plate at a velocity of about 7.8 cm per year, which is faster than the motion of the Indian plate. 
    • Lying 160 km off the coast of China, Taiwan was formed at a convergent boundary of the Philippine and Eurasian plates in the western Pacific Ocean. It is a country of strong earthquakes.

    Why other countries should take lesson from Taiwan in quake resilience?

    • In 1999, the Chi-Chi earthquake of magnitude 7.7 occurred in the central part of Taiwan and impacted the western region. It killed more than 2,430 people and left 11,305 wounded. It caused more than 50,000 buildings to collapse and partially damaged as many.
    • In 2024, Hualien earthquake killed at least 13 people and injured about 1,000. Most of the deaths were caused by earthquake-triggered rockfalls and not by toppled buildings. Despite being of nearly comparable magnitude, the 2024 earthquake has caused minimal damage compared to the 1999 earthquake.

    Taiwan’s earthquake preparedness

    • Advanced Monitoring and Early Warning Systems: Taiwan boasts the most advanced earthquake-monitoring network and early warning systems, allowing for quick detection and alerting of seismic activity.
    • Public Awareness Campaigns and Drills: Widespread awareness campaigns and regular drills on earthquake safety have significantly improved the public’s understanding of earthquake risks and proper safety protocols.
    • Government Regulations and Incentives: The government constantly updates earthquake safety requirements for both new and existing buildings. Additionally, incentives such as subsidies are offered to residents to improve the quake resistance of buildings, encouraging compliance with safety standards.
    • Scientific Judgments for Seismic Risk: Utilizing knowledge of earthquake frequency and severity in different areas, Taiwan is able to make sound scientific judgments regarding seismic risk.
    • Utilization of New Technologies: Taiwan employs cutting-edge technologies such as seismic dampers and base isolation systems to enhance building resilience. For example, Taipei 101, the nation’s iconic building, features a tuned mass damper—a massive steel sphere suspended by cables within the tower—which acts as a pendulum to counteract building motion during earthquakes.

    What India can learn from Taiwan?

    • Importance of Seismic Safety Regulations: India, especially in tectonically unstable regions like the Himalayas, must prioritize seismic safety regulations in all infrastructure projects.  
    • Customized Seismic Codes: Similar to Taiwan, India should develop seismic codes tailored to specific regions based on local earthquake activity, building types, and construction materials. These customized codes can better address the unique seismic risks faced by different parts of the country.
    • Utilization of Traditional Architectural Styles: In some parts of India, traditional architectural styles may possess inherent earthquake resistivity. By rediscovering and encouraging the use of these traditional techniques, India can promote earthquake-resistant building practices that are culturally and environmentally sustainable.
    • Integration of Seismic Zonation Maps: Indian code IS 1893 already specifies seismic designs based on seismic zonation maps. It’s crucial for India to integrate these maps effectively into urban planning and construction practices to ensure that buildings are designed and located in accordance with seismic risk assessments.

    Conclusion

    Earthquakes is natural disasters with unpredictable occurrences, can have devastating effects on society. However, their impact can be mitigated through preventive measures such as early warning systems, construction regulations, and raising awareness about earthquake preparedness.

    Mains PYQ 

    Q 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 IAS/2021)

    Mains question for practice 

    Q Analyzing Taiwan’s earthquake preparedness following the April 3rd 7.4 magnitude earthquake, explore lessons for India’s earthquake resilience strategy.

  • Mount Ruang in Indonesia Erupts

    Why in the news?

    Indonesia witnessed a series of eruptions from Mount Ruang, a stratovolcano located in North Sulawesi Province.

    About Mount Ruang 

    • Ruang is situated in the Sangihe Islands arc, North Sulawesi, Indonesia.
    • It comprises an island that is 4 by 5 kilometers wide, with a summit containing a partial lava dome reaching an altitude of 725 meters (2,379 ft).
    • From its summit, peaks such as Klabat, Siau, and Ternate can be observed in the south, north, and east, respectively.
    • The volcano’s first recorded eruption was in 1808.

    Why so many volcanic eruptions in Indonesia this year?

    • Indonesia, an archipelago of 270 million people, has 120 active volcanoes.
    • It is prone to volcanic activity because it sits along the “Ring of Fire,” a horseshoe-shaped series of seismic fault lines around the Pacific Ocean.

    What is the Pacific ‘Ring of Fire’?

    • The Pacific ‘Ring of Fire’ or Pacific Rim, or the Circum-Pacific Belt, is an area along the Pacific Ocean that is characterized by active volcanoes and frequent earthquakes.
    • Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire.
    • It is home to about 75 per cent of the world’s volcanoes – more than 450 volcanoes.
    • Also, about 90 per cent of the world’s earthquakes occur here.

    Its spread

    • Its length is over 40,000 kilometres and traces from New Zealand clockwise in an almost circular arc covering Tonga, Kermadec Islands, Indonesia.
    • It is moving up to the Philippines, Japan, and stretching eastward to the Aleutian Islands, then southward along the western coast of North America and South America.

    Seismic activity of the region

    • The area is along several tectonic plates including the:
    1. Pacific plate,
    2. Philippine Plate,
    3. Juan de Fuca plate,
    4. Cocos plate,
    5. Nazca plate, and
    6. North American plate.
    • The movement of these plates or tectonic activity makes the area witness abundant earthquakes and tsunamis every year.
    • Along much of the Ring, tectonic plates move towards each other creating subduction zones.

    PYQ:

    [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?

    (a) 1 only

    (b) 2 and 3

    (c) 3 only

    (d) 1 and 3

  • On India’s ‘heat action plans’ | Explained

    Why in the news?

    Come summer, we are used to seeing heat alerts from the India Meteorological Department (IMD) for various parts of India. This year, these alerts began in February itself.

    What is a heatwave?

    • According to the IMD, the definition of a heatwave depends on the physiography of regions.
    • The IMD will declare a heatwave if the maximum temperature recorded at a station is 40 degrees Celsius or more in the plains, 37 degrees Celsius or more in the coast, and 30 degrees Celsius or more in the hills.

    Heat Action Plans (HAPs) to tackle heatwave 

    • Aim: HAPs aim to increase preparedness and lower the adverse impacts of extreme heat by outlining strategies and measures to prepare for, address, and recover from heat waves.
      • The National Disaster Management Authority and IMD are reported to be working with 23 States to develop HAPs.
    • Issue with Database: There is no centralized database on HAPs, but at least 23 HAPs exist at the State and city level, with a few States, such as Odisha and Maharashtra, laying out district-level HAPs.

    Key components of Heat Action Plans (HAPs)  

    Limitation 

    • Challenges related to Determining Heatwaves: While a national threshold is currently used to determine heatwaves, determining them at smaller scales such as states, districts, and cities poses a challenge due to variations in local factors like the urban heat island effect, type of roofing, and proximity to water or green bodies, as well as humidity.
    • Inconsistent Methods and Vulnerability Assessments: The methods used for vulnerability assessments in HAPs are inconsistent because of the diverse physiography of regions
    • Addressing Vulnerable Populations: While HAPs prioritize protecting vulnerable populations, targeted interventions often fail to account for varying needs based on local socio-economic and demographic factors.
    • Resource Allocation and Financing: Implementation of HAPs varies depending on local government priorities and available capacities because at the local level Fund crunch.
    • Integration and Collaboration: HAPs are currently standalone plans with limited finance, highlighting the need for integration with broader action plans promoting urban resilience and climate adaptation to pool resources effectively.

    Way Forward:

    • Determination at Local Scales: Invest in local monitoring systems that capture variations in temperature, humidity, and other relevant factors.
    • Standardizing Methods: Establish guidelines for conducting vulnerability assessments that account for diverse physiography and local context.
    • Tailoring Interventions: Conduct comprehensive community consultations to understand the unique needs of vulnerable populations in different localities.
    • Funding and Resources: Advocate for increased funding for HAPs at the national and local levels through budget allocations, grants, and public-private partnerships.
    • Integration and Collaboration: Establish inter-agency task forces or committees to coordinate HAPs with other relevant initiatives, such as urban planning, public health, and disaster management.

    Mains PYQ 

    Q Climate change’ is a global problem. How India will be affected by climate change? How Himalayan and coastal states of India will be affected by climate change? (UPSC IAS/2017)

  • India’s Arctic imperative

    Why in the news? 

    The Indian government appears interested in capitalizing on seabed mining and resource exploitation in the Arctic

    About Artice Region:

    • The Arctic region is rich in energy resources, including oil, natural gas, and renewable energy sources such as wind, solar, hydro, geothermal, and tidal power.
    • The Arctic covers an area of approximately 8 million square kilometers, with interests belonging to Denmark, Canada, Iceland, Finland, Russia, Norway, Sweden, and the United States

    The reason behind the growing interest in the Arctic Region:

    • Climate Change Concerns: India’s increased interest in the Arctic stems from scientific data revealing accelerated warming in the region.
    • Trade Route Opportunities: India seeks to capitalize on the opening up of Arctic sea routes, particularly the Northern Sea Route, to enhance its trade efficiency.
    • Geopolitical Considerations: India’s focus on the Arctic is also driven by geopolitical factors, including concerns over China’s expanding presence and Russia’s decisions regarding access to Arctic routes.
    • Historical Engagement: India’s involvement in the Arctic dates back to 1920 with the signing of the Svalbard Treaty.

    Indian Initiatives:

    • Arctic Council: As an Observer in the Arctic Council, India actively participates in various working groups and expert meetings. India’s involvement in these discussions helps in understanding Arctic governance issues and contributes to the development of sustainable policies for the region.
    • INS Himadri: In 2019, India launched its first scientific expedition to the Arctic with the INS Himadri, an ice-class research vessel. The expedition aimed to study climate change, oceanography, and marine biodiversity, furthering India’s expertise in polar research.
    • PAME: India’s commitment to sustainable development in the Arctic is reflected in its engagement with Arctic Council initiatives like the ‘Protection of the Arctic Marine Environment’ (PAME).

    Way Forward – Potential for Collaboration:

    • Green Energy and Clean Industries: India’s current policy emphasizes cooperation with Arctic countries, particularly Norway, in green energy and clean industries. This aligns with India’s goal of positioning itself as a responsible stakeholder in global environmental initiatives.
    • Transformational Partnership: Collaboration with Norway could be transformative for India, offering opportunities for increased participation in Arctic Council working groups
    • Scientific Research and Environmental Protection: A partnership with Norway is expected to focus on scientific research, climate, and environmental protection. These areas align with India’s Arctic Policy pillars, emphasizing the importance of addressing environmental challenges through research and cooperation.

  • Mount Etna’s Volcanic Vortex Rings: A Rare Natural Phenomenon

    Mt. Etna

    Why in the news?

    Mount Etna, located on the east coast of Sicily in Italy recently gained attention for emitting circular rings of vapor from its summit, known as volcanic vortex rings.

    About Mount Etna

    • Mount Etna is located on the east coast of Sicily, Italy.
    • It is an active stratovolcano, characterized by its conical shape formed by layers of hardened lava, ash, and volcanic rocks.
    • It is Europe’s tallest active volcano, standing at approximately 3,329 meters (10,922 feet) above sea level.
    • It is one of the most active volcanoes in the world and has been erupting for thousands of years, with the first recorded eruption dating back to around 1500 BCE.
    • Mount Etna and its surrounding area have been designated as a UNESCO World Heritage Site since 2013, recognizing its geological significance and natural beauty.
    • It boasts five craters responsible for eruptions, alongside numerous vents along its slopes.

    What are Volcanic Vortex Rings?

    • Volcanic vortex rings are a rare phenomenon observed when gas, primarily water vapor, is rapidly released through a vent in the volcano’s crater, forming circular rings of smoke above the mountain.
    • This phenomenon, similar to smoke rings blown by cigarette smokers, occurs when gas is expelled through a nearly perfect circular vent in the crater.
    • These rings can rise in the air for up to 10 minutes but may disintegrate quickly under windy conditions.

    Volcanism in Italy

    • The volcanism of Italy is due chiefly to the presence, a short distance to the south, of the boundary between the Eurasian Plate and the African Plate.
    • Italy is a volcanically active country, containing the only active volcanoes in mainland Europe (while volcanic islands are also present in Greece, in the volcanic arc of the southern Aegean).
    • The lava erupted by Italy’s volcanoes is thought to result from the subduction and melting of one plate below another.
    • Other active volcanoes include Mt. Stromboli and Vesuvius.

    Historical and Recent Observations

    • Etna produces more vapor rings than any other volcano on Earth, making it a hotspot for studying this phenomenon.
    • The occurrence of volcanic vortex rings was first documented in 1724 at Mount Etna and Vesuvius in Italy, and has since been observed at various volcanoes worldwide.
    • Recent observations of this phenomenon have been reported at volcanoes in Alaska, Ecuador, Guatemala, Iceland, Italy, Japan, Vanuatu, New Zealand, and Nicaragua.

    Recent Volcanic Eruptions in News:

    Many of the world’s most active volcanoes are concentrated in the Pacific Ring of Fire, encompassing regions like New Zealand, Southeast Asia, Japan, and the western coast of the Americas. This volatile area also experiences about 90% of all earthquakes globally.

    • Kilauea, Hawaii: The Kilauea volcano in Hawaii captivated the world with a nearly nonstop eruption that began in 1983 and continued for an astonishing 35 years until 2018. Remarkably, it rekindled in 2021, with the eruption still ongoing.
    • Dukono, Indonesia: Erupting since August 1933, Dukono volcano in Indonesia stands as a testament to long-term volcanic activity, defying the passage of time.
    • Santa Maria, Guatemala: The eruption of Santa Maria in Guatemala commenced in June 1922 and persists to this day, underscoring the enduring nature of certain volcanic phenomena.
    • Yasur, Vanuatu: Yasur in Vanuatu first erupted around 1270 and has maintained its volcanic activity, continuing as of June 9, 2023.

    Understanding Volcanoes

    • Volcanoes are geological features characterized by openings or vents through which lava, tephra (small rocks), and steam erupt onto the Earth’s surface.
    • They result from both their own eruptions and the broader processes of tectonic plate movement.
    • Volcanic eruptions are essentially the result of magma, or molten rock, beneath the Earth’s surface rising, bubbling, and ultimately overflowing, much like boiling milk spilling out of a pot on a stove.
    • The magma seeks pathways to vents within the volcano, where it erupts and is expelled across the land and into the atmosphere, a phenomenon referred to as lava.

    Appearance Formation Eruption Style Notable Examples
    Cinder Cones Small, steep, conical Formed from basaltic magma with high gas content Often explosive eruptions with cinders/scoria Paricutin (Mexico), Sunset Crater (USA)
    Composite/Stratovolcanoes Tall and symmetrical Result from alternating layers of lava, ash, etc. Both explosive and effusive eruptions Mount St. Helens (USA), Mount Fuji (Japan)
    Shield Volcanoes Broad and gently sloping Primarily formed from basaltic magma Primarily non-explosive with extensive lava flows Mauna Loa, Mauna Kea (Hawaii)
    Lava Domes Rounded dome-like shape Formed from slow extrusion of viscous magma Typically non-explosive but can be dangerous Novarupta Dome (Alaska), Mount St. Helens’ Lava Dome (USA)

     

    PYQ:

    [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?

    (a) 1 only

    (b) 2 and 3

    (c) 3 only

    (d) 1 and 3

  • In news: Total Solar Eclipse

    Why in the news?

    A rare Total Solar Eclipse will be visible across North America on April 8.

    What are Eclipses?

    • Eclipses are astronomical events that occur when the sun, moon, and Earth align in specific ways.
    • There are two primary types of eclipses: solar and lunar.
    1. A solar eclipse happens when the moon comes between the sun and Earth during a new moon, blocking out the sun’s light.
    2. Conversely, a lunar eclipse occurs when the Earth is positioned between the sun and the moon during a full moon, casting a shadow on the moon.

    What is a Total Solar Eclipse?

    • During a total solar eclipse, the moon passes between the sun and Earth, entirely covering the face of the sun along a small path of our planet’s surface.
    • This is called the “path of totality.”
    • The daytime sky turns dark, similar to dusk or dawn, and nocturnal animals have been known to wake up, confused into believing night has arrived.

    Stages of a Total Solar Eclipse

    A total solar eclipse unfolds in several distinct stages.

    1. It starts with a partial eclipse phase as the moon begins to pass between Earth and the sun, partially blocking it and leaving the sun looking like it has a crescent shape.
    2. In the subsequent Baily’s Beads phase, points of light from the sun shine around the moon’s edges because of the irregular lunar topography, producing small beads of light.
    3. In the diamond ring phase, a single bright spot appears along the lunar edge even as the sun’s atmosphere leaves a ring of light around the moon. This phenomenon precedes totality.
    4. After totality, the other phases repeat as the moon keeps moving along its path until the eclipse ends.

    Other types of solar eclipses:

    1. Partial Solar Eclipse
    • This happens when the sun, moon and Earth are not exactly lined up.
    • The sun appears to have a dark shadow on only a small part of its surface.
    1. Annular Solar Eclipse
    • An annular eclipse happens when the moon is farthest from Earth. Because the moon is farther away from Earth, it seems smaller. It does not block the entire view of the sun. The moon in front of the sun looks like a dark disk on top of a larger sun-coloured disk. This creates what looks like a ring around the moon.
    • During a solar eclipse, the moon casts two shadows on Earth. The first shadow is called the Umbra. This shadow gets smaller as it reaches Earth. It is the dark centre of the moon’s shadow.
    • The second shadow is called the Penumbra. The penumbra gets larger as it reaches Earth. People standing in the penumbra will see a partial eclipse. People standing in the umbra will see a total eclipse.

    Why don’t solar eclipses happen at every New Moon?

    • The reason is that the Moon’s orbit tilts 5° to Earth’s orbit around the Sun.
    • Astronomers call the two intersections of these paths nodes.
    • Eclipses only occur when the Sun lies at one node and the Moon is at its New (for solar eclipses) or Full (for lunar eclipses) phase.
    • During most (lunar) months, the Sun lies either above or below one of the nodes, and no eclipse happens.

    PYQ:

    2013:

    Consider the following phenomena

    1. Size of the sun at dusk

    2. Colure of the sun at dawn

    3. Moon being visible at dawn

    4. Twinkle of stars in the sky

    5. Polestar being visible in the sky

    Which of the above are optical illusions?

    (a) 1, 2 and 3

    (b) 3, 4 and 5

    (c) 1, 2 and 4

    (d) 2, 3 and 5

     

    Practice MCQ:

    Which of the following statements best characterizes a Total Solar Eclipse?

    (a) A total solar eclipse occurs when the Moon partially blocks the Sun, leaving a visible ring of sunlight around the Moon’s silhouette.

    (b) During a total solar eclipse, the Moon completely covers the Sun, casting a shadow on a narrow path on the Earth’s surface called the umbra.

    (c) Total solar eclipses occur more frequently than partial solar eclipses due to the precise alignment of the Sun, Earth, and Moon.

    (d) Total solar eclipses can only be observed from specific locations on Earth, making them rare and highly sought-after astronomical events.

  • In news: Ramapo Fault

    Why in the news?

    • An earthquake of magnitude 4.8 hit the New York City in a rare event.
    • The Ramapo Fault in Appalachian Mountains near New Jersey is a being considered as a reason behind this earthquake.

    Appalachian Mountains

    • The Appalachian Mountains extend from the Canadian province of Newfoundland and Labrador in the north to central Alabama in the southern US.
    • The total length of the Appalachian Mountain range is approximately 2,200 miles (3,500 kilometers), making it one of the longest mountain chains in the world.
    • Geologically, it is one of the oldest mountain ranges on Earth, formed over 480 million years ago during the Ordovician Period. They are considered a Paleozoic mountain range.
    • They were formed through a series of tectonic collisions and uplift events, including the assembly of the supercontinent Pangaea.
    • The highest peak in the range is Mount Mitchell in North Carolina, standing at an elevation of 6,684 feet (2,037 meters) above sea level.
    • The Appalachian Mountains hold cultural significance for various indigenous tribes, including the Cherokee, as well as early European settlers who established communities in the region.

    About Ramapo Fault

    • Fault lines are fractures in the Earth’s crust that facilitate movement of tectonic plates, triggering earthquakes.
    • The Ramapo Fault is resulted from tectonic activity associated with the breakup of the supercontinent Pangaea during the Mesozoic Era.
    • It is primarily a right-lateral strike-slip fault, formed by horizontal movement along the fault line due to the ongoing motion between the North American and Eurasian plates.
    • While the Ramapo Fault is not as seismically active as faults in other regions, it has experienced earthquakes in the past and remains a potential source of seismic hazards.

    Geographical Distribution:

    • The fault extends across three states in the northeastern United States: Pennsylvania, New Jersey, and New York.
    • The fault crosses various topographic features, including rift valleys, hills, and ridges, reflecting the diverse geological history of the region.
    • It intersects with the Appalachian Mountains, influencing the overall topography of the surrounding areas.

    PYQ:

    [2012] When you travel in Himalayas, you will see the following:

    1.    Deep gorges

    2.    U-turn river courses

    3.    Parallel mountain ranges

    4.    Steep gradients causing land-sliding

    Which of the above can be said to be the evidences for Himalayas being young fold mountains?

    (a) 1 and 2 only

    (b) 1, 2 and 4 only

    (c) 3 and 4 only

    (d) 1, 2, 3 and 4

     

  • Taiwan’s Earthquake and the Pacific Ring of Fire

    Why in the news?

    • Taiwan was struck by its most powerful earthquake in at least 25 years.
    • Its susceptibility to earthquakes is attributed to its location along the Pacific “Ring of Fire” where a majority of the world’s seismic activity occurs.
    • Taiwan is primarily influenced by the collision of the Philippine Sea Plate and the Eurasian Plate.

    What is the Pacific ‘Ring of Fire’?

    • The Pacific ‘Ring of Fire’ or Pacific Rim, or the Circum-Pacific Belt, is an area along the Pacific Ocean that is characterized by active volcanoes and frequent earthquakes.
    • Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire.
    • It is home to about 75 per cent of the world’s volcanoes – more than 450 volcanoes.
    • Also, about 90 per cent of the world’s earthquakes occur here.

    Its spread

    • Its length is over 40,000 kilometres and traces from New Zealand clockwise in an almost circular arc covering Tonga, Kermadec Islands, Indonesia.
    • It is moving up to the Philippines, Japan, and stretching eastward to the Aleutian Islands, then southward along the western coast of North America and South America.

    Seismic activity of the region

    • The area is along several tectonic plates including the Pacific plate, Philippine Plate, Juan de Fuca plate, Cocos plate, Nazca plate, and North American plate.
    • The movement of these plates or tectonic activity makes the area witness abundant earthquakes and tsunamis every year.
    • Along much of the Ring, tectonic plates move towards each other creating subduction zones.
    • One plate gets pushed down or is subducted by the other plate.
    • This is a very slow process – a movement of just one or two inches per year.
    • As this subduction happens, rocks melt, become magma and move to Earth’s surface and cause volcanic activity.

    PYQ:

    2020: Discuss the geophysical characteristics of Circum-Pacific Zone.