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Subject: Geographical Features

  • ‘Churachandpur Mao Fault’ in Mizoram

    Mizoram’s zone of “scary” earthquakes is caught between two subterranean faults called the ‘Churachandpur Mao Fault’.

    Try this question from CSE Mains 2014:

    Q.Why are the world’s fold mountain systems located along the margins of continents? Bring out the association between the global distribution of Fold Mountains and the earthquakes and volcanoes.

    Churachandpur-Mao Fault (CMF)

    • The CMF is named after two places in Manipur and runs north-south into Myanmar along the border of Champhai.
    • The Mat Fault runs northwest-southeast across Mizoram, beneath river Mat near Serchhip.
    • It is defined by straight valleys; most prominent being between Kangpokpi and Maram region of Mizoram.
    • The fault takes a north-easterly trend from Maram where the fault zone is characterized by active landslides during the monsoon.

    Why study CMF?

    • Faults are discontinuities or cracks that are the result of differential motion within the earth’s crust.
    • Vertical or lateral slippage of the crust along the faults causes an earthquake.

  • Rapid Intensification of Cyclones

    Tropical cyclones remain the deadliest natural climate hazard that causes an unacceptably high loss of life, property and infrastructure.  Global warming has already resulted in a detectable increase in the number of higher intensity cyclones as well as their intensification.

    Also read:

    [Burning Issue] Tropical Cyclones and India

    Try this question:

    Q. The Marsupial Theory often seen in news is related to which of the climatic phenomena?

    a) Heatwaves b) Monsoon Variability c) Formation of Cyclones d) Thunderstorms

    What is Rapid Intensification of Cyclones?

    • RI is defined as an increase in maximum sustained winds by at least 55 km/hour in a 24-hour period.
    • Such acceleration can only come with a rapid drop in the pressure in the eye of the cyclone.
    • Rapid intensification (RI) is making cyclone forecasts harder and intense cyclones with RI are expected to grow in number.
    • The lack of understanding of the transition from a seedling of a cyclone, like a low-pressure system to a tropical storm, limits extending the forecast lead times.

    Factors causing RI

    The most important environmental factors for cyclone genesis are-

    • the rotation or vorticity of a low-pressure system at the surface;
    • sea surface temperatures or the volume of warm water available;
    • the vertical motion of air in this low-pressure system;
    • the amount of humidity available in the middle atmosphere and
    • the vertical shear or the change in winds from the surface to the upper atmosphere.

    MJO and Cyclones

    • Madden-Julian Oscillations as they are known, dominate the tropics during October-April by propagating from the western Indian Ocean into the eastern Indian Ocean, across the Indonesian seas into the Pacific Ocean.
    • Referred to as MJOs, these Madden-Julian Oscillations throw seeds of rotational low-pressure systems over the Indian and the Pacific Oceans.
    • And thus, MJOs show a strong association with cyclogenesis, especially for the post-monsoon season.

    Impacts of MISO

    • Monsoon Intraseasonal Oscillations (MISO) are alternating periods of heavy and minimal rainfall, each lasting for about a month or so and tending to follow a cyclical, northward shifting pattern from the equator to southern Asia.
    • While the strong vertical shear suppresses cyclones during the monsoon season, MISOs influence cyclone genesis during the pre-monsoon season.

    Other factors

    • At longer timescales, phenomena like the El Niño and La Niña influence not only the number of cyclone seeds but also the location and the expanse of warm water.
    • For example, during the pre-monsoon season of La Niña year, the region of warm water over the Bay of Bengal increases. This leads cyclones to travel longer and grow stronger than during an El Niño year.
    • Over the Pacific Ocean, on the other hand, it is the El Niño that provides a larger swath of warm water and more intense cyclones.
    • West Africa produces waves called easterly waves that propagate west from land onto the tropical Atlantic Ocean and sow the seeds for most hurricanes.
    • Extensive analysis has produced theories that are evocatively called the Marsupial Theory — a wave pouch that allows cyclones to grow, or waves interacting to produce a Kelvin cat’s eye, which is a ‘sweet-spot’ for the birth of a cyclone.

  • The lost continent of Zealandia

    A new map has revealed the lost continent of Zealandia.

    The ocean relief can be divided into various parts such as Continental Shelf, Continental Slope, Continental Rise or Foot, Deep Ocean basins, Abyssal plains & Abyssal Hills, Oceanic Trenches, Seamounts and Guyots.

    Revise these ocean bottom relief features from your basic references.

    Also revise India’s Deep Ocean Mission.

    About Zealandia

    • Zealandia — or Te Riu-a-Māui, as it’s referred to in the indigenous Māori language — is a 2 million-square-mile (5 million square kilometres) continent east of Australia, beneath modern-day New Zealand.
    • Scientists discovered the sprawling underwater mass in the 1990s, then gave it formal continent status in 2017.
    • Still, the “lost continent” remains largely unknown and poorly studied due to its Atlantean geography.

    Its formation

    • It is a group of submerged pieces of crust that separated from the ancient supercontinent Gondwana about 85 million years ago.
    • Gondwana was formed when Earth’s ancient supercontinent, Pangea, split into two fragments.
    • Laurasia was transformed into North America, Asia, and Europe, while Gondwana became Africa, South America, Australia, and Antarctica.
    • But land masses continued to be rearranged afterwards, with Zealandia breaking off Gondwana.

    Data revealed by the new map

    • The new maps reveal Zealandia’s bathymetry (the shape of the ocean floor) as well as its tectonic history, showing how volcanism and tectonic motion have shaped the continent over millions of years.
    • Data for the bathymetric map was provided by the Seabed2030 project — a global effort to map the entire ocean floor by 2030.

    Why call it a continent?

    • Zealandia was classified as a “microcontinent,” as the island of Madagascar, until 2017.
    • But according to Mortimer, it has all the requirements to be classified as a continent.
    • It has defined boundaries; it occupies an area of over one million square kilometres and is elected above the ocean crust.

    Also read: https://www.civilsdaily.com/news/seabed-2030-project/

  • What is ‘Last Glacial Maximum’?

    Researchers analysed simulations of this past climate and predicted that the ongoing climate change could reawaken an ancient climate pattern of the Indian Ocean Region (IOR).

    Try this question from CSP 2017:

    Q.With reference to ‘Indian Ocean Dipole (IOD)’, sometimes mentioned in the news while forecasting Indian monsoon, which of the following statements is/are correct?

    1. IOD phenomenon is characterized by a difference in sea surface temperature between tropical Western Indian Ocean and tropical Eastern Pacific Ocean.

    2. An IOD phenomenon can influence El Nino’s impact on the monsoon.

    Select the correct Option using the code given below:

    (a) Only 1

    (b) Only 2

    (c) Both 1 and 2

    (d) Neither 1 nor 2

    The Last Glacial Maximum

    • The Last Glacial Maximum (LGM) was the most recent time during the Last Glacial Period that ice sheets were at their greatest extent.
    • Vast ice sheets covered much of North America, Northern Europe, and Asia and profoundly affected Earth’s climate by causing drought, desertification, and a large drop in sea levels.
    • Growth of ice sheets commenced 33,000 years ago and maximum coverage was between 26,500 years and 19–20,000 years ago, when deglaciation commenced in the Northern Hemisphere.
    • It caused an abrupt rise in sea level.

    Shells predict IOR climate variability

    • By studying microscopic zooplankton called foraminifera, the team had published a paper in 2019 which first found evidence from the past of an Indian Ocean El Niño.
    • Foraminifera builds a calcium carbonate shell, and studying these can tell us about the properties of the water in which they lived.
    • The team measured multiple individual shells of foraminifera from ocean sediment cores and was able to reconstruct the sea surface temperature conditions of the past.
    • The Indian Ocean has the capacity to harbour much larger climate variability than observed during the last few decades or a century.

    Lessons to learn

    • There are many lessons to be learnt from this cooler period about our warmer future.
    • As it is, under present-day conditions, changes in the Indian Ocean Dipole and the El Niño–Southern Oscillation strongly affect Indian Monsoon variability from year to year.
    • If the hypothesized ‘equatorial mode’ emerges in the near future, it will pose another source of uncertainty in rainfall prediction and will likely amplify swings in monsoon rainfall.
    • It could bring more frequent droughts to East Africa and southern India and increased rainfall over Indonesia.

    Back2Basics

    What is the Indian Ocean Dipole? Explain its connection with the Indian monsoons

  • What is the Anthropause Period?

    Researchers in the UK are set to study the “Anthropause”, a term they have coined to refer to the coronavirus-induced lockdown period and its impact on other species.

    Practice question for mains:

    Q. What is the significance of declaring Anthropocene epoch? Discuss how it is different from any geological events. Discuss the Anthropause Period.

    Anthropause Period

    • Researchers have suggested the lockdown period, which is also being referred to as the “Great Pause”, be referred to with a more precise term.
    • It is referred specifically to a considerable global slowing of modern human activities, notably travel.
    • The unprecedented curbs imposed on millions of people around the world, mainly due to restrictions in travel, led to reports of unusual animal behaviour.
    • For instance, there were pumas sighted in Chile’s Santiago, jackals in the parks of Tel Aviv in Israel, dolphins in the waters of Italy and even a monkey fight on the streets of Thailand.
    • The researchers believe studying this period will provide valuable insights into the relationship between human-wildlife interactions in the 21st century.

    What do the researchers hope to find?

    • As a result of the lockdown, nature appears to have changed, especially in urban environments, since not only are there now more animals, but also some “unexpected visitors.”
    • In their outline, researchers mention how the scientific community can use these “extraordinary circumstance” provided by global lockdowns to understand how human activity affects wildlife.
    • On the other hand, there are some animals for which the lockdown may have made things more challenging.
    • For instance, for various urban-dwelling animals, such as rats, gulls and monkeys who depend on food provided or discarded by humans, the lockdown would have made life more difficult.

    Why is studying the lockdown important?

    • Expanding human populations continue to transform their environments at unprecedented rates.
    • Further, because the reduction in human activity during the lockdown on both land and sea has been “unparalleled” in recent history, the effects have been “drastic, sudden and widespread”.
    • Essentially, this gives them a chance to study the extent to which modern human mobility affects wildlife.
    • The study can be linked can help provide insights that may be useful in preserving global biodiversity, maintaining the integrity of ecosystems and predicting global zoonoses and environmental changes.

    Back2Basics

    https://www.civilsdaily.com/news/anthropocene-as-earths-new-epoch/

  • Seabed 2030 Project

    The Seabed 2030 Project has finished mapping nearly one-fifth of the world’s ocean floor.

    The ocean relief can be divided into various parts such as Continental Shelf, Continental Slope, Continental Rise or Foot, Deep Ocean basins, Abyssal plains & Abyssal Hills, Oceanic Trenches, Seamounts and Guyots.

    Revise these ocean bottom relief features from your basic references.

    Also revise India’s Deep Ocean Mission.

    The Seabed 2030 Project

    • The global initiative is a collaboration between Japan’s non-profit Nippon Foundation and the General Bathymetric Chart of the Oceans (GEBCO).
    • It is the only intergovernmental organisation with a mandate to map the entire ocean floor and traces its origins to the GEBCO chart series initiated in 1903 by Prince Albert I of Monaco.
    • The project was launched at the UN Ocean Conference in 2017, and coordinates and oversees the sourcing and compilation of bathymetric data from different parts of the world’s ocean.

    What’s so special about this project?

    • In the past, satellites and planes carrying altimeter instruments have been able to provide large swathes of data about the ocean floor.
    • The Seabed 2030 Project, however, aims to obtain higher quality information that has a minimum resolution of 100 m at all spots.
    • It is using equipment such as deepwater hull-mounted sonar systems, and more advanced options such as Underwater Vehicles (AUVs).
    • For this, the project aims to rope in governments, private companies, and international organisations to acquire data.

    Progress of the project

    • Since the launch of the project in 2017, the surveying of the ocean bed as per modern standards has gone up from around 6 per cent to 19 per cent.
    • The project has added 1.45 crore square kilometres of new bathymetric data to its latest grid.

    Why is the study of the ocean floor important?

    • Ocean topography: The knowledge of bathymetry — the measurement of the shape and depth of the ocean floor, is instrumental in understanding several natural phenomena, including ocean circulation, tides, and biological hotspots.
    • Navigation: It also provides key inputs for navigation, forecasting tsunamis, exploration for oil and gas projects, building offshore wind turbines, fishing resources, and for laying cables and pipelines. This data becomes highly valuable during disaster situations.
    • Climate Change study: Importantly, the maps would also ensure a better understanding of climate change, since floor features including canyons and underwater volcanoes influence phenomena ocean currents. These ocean currents act as conveyor belts of warm and cold water, thus influencing the weather and climate.
    • Marine conservation: A map of the entire global ocean floor would also help further achieve the United Nations Sustainable Development Goal to conserve and sustainably use oceans, seas and marine resources.

    Try this PYQ from CSP 2012:

    Q.Consider the following factors:

    1. Rotation of the Earth
    2. Air pressure and wind
    3. Density of ocean water
    4. Revolution of the Earth

    Which of the above factors influence the ocean currents?

    (a) 1 and 2 only

    (b) 1, 2 and 3

    (c) 1 and 4

    (d) 2, 3 and 4

  • ‘Ring of Fire’ Solar Eclipse

    A rare celestial event, an annular solar eclipse popularly called as the ‘ring of fire’ eclipse, will be visible on June 21, 2020 from some parts of Northern India. The first solar eclipse of this year takes place on the summer solstice, which is the longest day in the Northern Hemisphere.

    Try this question from CSP 2019:

    Q. On 21st June, the Sun

    (a) Does not set below the horizon at the Arctic Circle

    (b) Does not set below the horizon at Antarctic Circle

    (c) Shines vertically overhead at noon on the Equator

    (d) Shines vertically overhead at the Tropic of Capricorn

    What is the Solar Eclipse?

    • A Solar Eclipse happens when the moon while orbiting the Earth comes in between the sun and the Earth, due to which the moon blocks the sun’s light from reaching the Earth, causing an eclipse of the sun or a solar eclipse.
    • According to NASA, people who are able to view the total solar eclipse are in the centre of the moon’s shadow as and when it hits the Earth.
    • There are three types of eclipses: one is a total solar eclipse, which is visible only from a small area on Earth. A total solar eclipse happens when the sun, moon and Earth are in a direct line.
    • The second type of a solar eclipse is a partial solar, in which the shadow of the moon appears on a small part of the sun.

    Annular Solar Eclipse

    • The third kind is an annular solar eclipse, which happens when the moon is farthest from the Earth, which is why it seems smaller.
    • In this type of an eclipse, the moon does not block the sun completely, but looks like a “dark disk on top of a larger sun-coloured disk” forming a “ring of fire”.
    • Furthermore, during a solar eclipse, the moon casts two shadows on the Earth; the first one is called the umbra, which gets smaller as it reaches the Earth.
    • The second one is called the penumbra, which gets larger as it reaches the Earth.
    • According to NASA, people standing in the umbra see a total eclipse and those standing in the penumbra see a partial eclipse.

    Why the study of solar eclipse is crucial?

    • One of the reasons that NASA studies solar eclipses is to study the top layer of the sun called the corona.
    • During an annular eclipse, NASA uses ground and space instruments to view this top layer when the sun’s glare is blocked by the moon.

    Back2Basics: Summer Solstice

    • The summer solstice occurs when one of the Earth’s poles has its maximum tilt toward the Sun.
    • It happens twice yearly, once in each hemisphere (Northern and Southern).
    • For that hemisphere, the summer solstice is when the Sun reaches its highest position in the sky and is the day with the longest period of daylight.
    • Within the Arctic circle (for the northern hemisphere) or Antarctic circle (for the southern hemisphere), there is continuous daylight around the summer solstice.
    • On the summer solstice, Earth’s maximum axial tilt toward the Sun is 23.44°. Likewise, the Sun’s declination from the celestial equator is 23.44°.

  • Lonar Lake colour changes to pink

    The colour of water in Maharashtra’s Lonar Lake, formed after a meteorite hit the Earth some 50,000 years ago, has changed to glaring.

    Make a note of all saltwater lakes in India. Few of them are Pulicat, Pangong Tso, Chilika, and Sambhar Lakes etc.

    About Lonar Lake

    • Lonar Lake, also known as Lonar crater, is a notified National Geo-heritage Monument, saline (pH of 10.5), Soda Lake, located at Lonar in Buldhana district, Maharashtra.
    • It was created by an asteroid collision with earth impact during the Pleistocene Epoch.
    • It is one of the four known, hyper-velocity, impact craters in basaltic rock anywhere on Earth.
    • It sits inside the Deccan Plateau—a massive plain of volcanic basalt rock created by eruptions some 65 million years ago.
    • Its location in this basalt field suggested to some geologists that it was a volcanic crater.

    Why there’s a color change?

    • The salinity and algae can be responsible for this change.
    • There is no oxygen below one meter of the lake’s water surface.
    • There is an example of a lake in Iran, where water becomes reddish due to increase in salinity.
    • The level of water in the Lonar Lake is currently low as compared to the few past years and there is no rain to pour fresh water in it.
    • The low level of water may lead to increased salinity and change in the behaviour of algae because of atmospheric changes.

  • Challenger Deep: the deepest spot in the ocean

    On June 7, astronaut and oceanographer Kathy Sullivan, who was the first American woman to walk in space in 1984, became the first woman and the fifth person in history to descend to the deepest known spot in the world’s oceans, called the Challenger Deep in the Mariana Trench.

    The ocean relief can be divided into various parts such as Continental Shelf, Continental Slope, Continental Rise or Foot, Deep Ocean basins, Abyssal plains & Abyssal Hills, Oceanic Trenches, Seamounts and Guyots.

    Revise these ocean bottom relief  features from your basic references.

    Also revise India’s Deep Ocean Mission.

    What is Challenger Deep?

    • The Challenger Deep is the deepest known point in the Earth’s seabed hydrosphere (the oceans), with a depth of 10,902 to 10,929 m.
    • The deepest part is called the Challenger Deep, which is located below the surface of the western Pacific Ocean.
    • The first dive at Challenger Deep was made in 1960 by Lieutenant Don Walsh and Swiss scientist Jacques Piccard on a submersible called ‘Trieste’.
    • The British Ship HMS Challenger discovered Challenger Deep between 1872-1876.
    • In 2012, film director James Cameron reached the bottom of the Mariana trench after a descent that lasted 2 hours and 36 minutes.
    • Cameron reached a depth of about 10,908 metres on a dive in his submersible called the ‘Deepsea Challenger’ and became the first to complete a solo submarine dive to this spot.

    Why explore deep oceans?

    • Ocean exploration, however, is not randomly wandering in hopes of finding something new.
    • It is disciplined and organized and includes rigorous observations and documentation of biological, chemical, physical, geological, and archaeological aspects of the ocean.
    • Most of the existing knowledge of the oceans comes from shallower waters, while deeper waters remain relatively unexplored, even as humans are relying more on these areas for food, energy and other resources.
    • Further, finding out more about the deep ocean areas can potentially reveal new sources for medical drugs, food, energy resources and other products.
    • Significantly, information from the deep oceans can also help to predict earthquakes and tsunamis, and help us understand how we are affecting and getting affected by the Earth’s environment.

    What does it take to reach the deep ocean?

    • Vehicles called Human Occupied Vehicles (HOVs) may be used that carry scientists to the deep sea.
    • Alternatively, there are unmanned Remotely Operated Vehicles (ROVs) that are linked to ships using cables and can be steered by scientists remotely.
    • Even so, it is difficult for most private citizens to travel more than 100 feet below the surface of the ocean.
    • Further, technical divers can go as deep as 500 feet or more, but with an array of tanks filled with different gas blends.

    Why is it so difficult to explore deep oceans?

    • Most recreational divers can’t explore more than about 120 feet down due to the amount of air needed to keep lungs pressurized at depth.
    • Such depths could lead to nitrogen narcosis, the intoxication by nitrogen that starts to set in around that depth (most of our atmosphere is nitrogen, not oxygen).
    • Waters at such depths of several kilometres exert tremendous pressure which human bodies cannot sustain.

  • Permafrost and the hazards of its Thawing

    The principal reason that led to the recent 20,000-tonne oil leak at an Arctic region power plant in Russia that is now being recognised is the sinking of ground surface due to permafrost thaw.

    Try this question from Mains 2017:
    Q. What is Cryosphere? How does the Cryosphere affect global climate?

    What is Permafrost?

    • Permafrost is ground that remains completely frozen at 0 degrees Celsius or below for at least two years.
    • It is defined solely based on temperature and duration.
    • The permanently frozen ground, consisting of soil, sand, and rock held together by ice, is believed to have formed during glacial periods dating several millennia.

    Where are they found?

    • These grounds are known to be below 22 per cent of the land surface on Earth, mostly in polar zones and regions with high mountains.
    • They are spread across 55 per cent of the landmass in Russia and Canada, 85 per cent in the US state of Alaska, and possibly the entirety of Antarctica.
    • In northern Siberia, it forms a layer that is 1,500 m thick; 740 m in northern Alaska.
    • At lower latitudes, permafrost is found at high altitude locations such as the Alps and the Tibetian plateau.

    How climate change is eating away at these grounds?

    • The Earth’s polar and high altitude regions — its principal permafrost reservoirs — are the most threatened by climate change.
    • Arctic regions are warming twice as fast compared to the rest of the planet, its current rate of temperature change being the highest in 2,000 years.
    • In 2016, Arctic permafrost temperatures were 3.5 degrees Celsius higher than at the beginning of the 20th century.
    • A study has shown that every 1 degree Celsius rise in temperature can degrade up to 39 lakh square kilometre due to thawing.
    • This degradation is expected to further aggravate as the climate gets warmer, putting at risk 40 per cent of the world’s permafrost towards the end of the century– causing disastrous effects.

    The threat to infrastructure

    • Thawing permafrost is also ominous for man-made structures overhead.
    • The Russian oil leak occurred recorded temperatures in Siberia at more than 10 degrees Celsius above average, and called them “highly anomalous” for the region where the power plant is located.
    • As temperatures rise, the binding ice in permafrost melts, making the ground unstable and leading to massive potholes, landslides, and floods.
    • The sinking effect causes damage to key infrastructure such as roads, railway lines, buildings, power lines and pipelines.
    • These changes also threaten the survival of indigenous people, as well as Arctic animals.

    A ticking time bomb

    • Beneath its surface, permafrost contains large quantities of organic leftover from thousands of years prior — dead remains of plants, animals, and microorganisms that got frozen before they could rot.
    • It also holds a massive trove of pathogens.
    • When permafrost thaws, microbes start decomposing this carbon matter, releasing greenhouse gases like methane and carbon dioxide.
    • Researchers have estimated that for every 1 degree Celsius rise in temperature, these grounds could release GHGs to the tune of 4-6 years’ of emissions from coal, oil, and natural gas.
    • Along with greenhouse houses, these grounds could also release ancient bacteria and viruses into the atmosphere as they unfreeze.

    Back2Basics
    https://www.civilsdaily.com/news/thawing-of-permafrost/

    Also read:

    Ambarnaya River Oil spill in Russia