Natural calamities - class-VIII

Radar is a primary tool used by meteorologists to track the movement, intensity, and structure of cyclones.

Lightning is caused by the buildup of static electricity in clouds, which occurs due to the collision of ice crystals and water droplets within the turbulent air.

• 108 is a free telephone number for emergency services in India.
• The 108 Emergency Response Service is a free emergency service providing integrated medical, police and fire emergency services.
• Hence 108 contact number is important at the time of disaster.
• So, the correct answer is '108'.

After a cyclone, downed power lines are a major hazard; avoiding them is a critical safety precaution to prevent electrocution.

Magma is the term used for molten rock that is located beneath the Earth's surface.

Once magma reaches the Earth's surface through a volcanic eruption, it is referred to as lava.

An anemometer is a type of weather instrument that measures wind speed. Some of these instruments measure both wind speed and wind direction. Anemometers are common at weather stations. A cup anemometer is a type of instrument that uses three or four hemispherical cups mounted on horizontal arms on a vertical rod.

Cyclones are characterized by both intense, strong winds and heavy rainfall, which often lead to flooding.

In India, the pre-monsoon and post-monsoon periods are prone to cyclones, with May and June being common months for these events.

Cyclones, typhoons, and hurricanes are all the same weather phenomenon, just named differently based on the region where they occur.

• A natural disaster is a major adverse event resulting from natural processes of the Earth; examples are floods, hurricanes, drought, landslide tornadoes, volcanic eruptions, earthquakes, tsunamis, etc that causes great damage or loss of life.
• A car accident is not a natural disaster it is caused by human negligence and does not lead to great damage or loss of life. Hence car accident is not a natural disaster.
• Hence All of the following is associated with the natural disaster except car accident.
• So, the correct answer is 'Car accident'.

The Chernobyl disaster in 1986 is widely considered the most severe nuclear accident in history in terms of cost and casualties.

During an earthquake, the standard safety advice is to 'drop, cover, and hold on', which includes taking shelter under a sturdy table to protect against falling debris.

Flooding is globally recognized as one of the most frequent and deadly natural disasters, causing significant loss of life annually.

An exclusively man-made disaster is bomb explosion. Bomb is an explosive weapon that uses the exothermic reaction of explosive material or provide an extremely sudden and evident release of energy. This is invented by humans and any disaster caused by it is exclusively man-made. while fire, floods, and famine are not exclusively man-made disasters. Nature itself trigger or aids in these disasters. Therefore they are not exclusively man-made. 

The word Tsunami is derived from the Japanese words 'tsu' (harbor) and 'nami' (wave).

A tsunami is a series of waves in a water body caused by the displacement of a large volume of water, typically due to earthquakes or volcanic eruptions.

Deforestation reduces natural buffers and soil stability, while global warming increases the frequency of extreme weather, both contributing significantly to disaster risks.

Chernobyl is the site of the world's worst nuclear disaster, which occurred in 1986 in what is now Ukraine.

Earthquakes can cause structural damage to buildings, trigger secondary disasters like floods (via dam failure or tsunamis), and destroy natural habitats.

The Richter scale is a logarithmic scale used to measure the magnitude of earthquakes, typically ranging from 0 to 9, though it is theoretically open-ended.

Seismology is the scientific study of earthquakes and the propagation of elastic waves through the Earth.

The point within the Earth where an earthquake rupture starts is called the hypocenter or focus, while the point directly above it on the surface is the epicenter.

Earthquakes are primarily caused by the movement of tectonic plates, which involves friction and tremors as they slide past or collide with each other.

The Richter scale is a logarithmic scale used to quantify the magnitude of an earthquake. Speedometers measure vehicle speed, and barometers measure atmospheric pressure.

Landslides are triggered by both natural and human-induced factors. Deforestation removes soil-stabilizing roots, while vibrations from machinery or traffic can destabilize slopes.

Cyclones cause widespread damage, including structural failure in communication systems, loss of biodiversity, and vegetation damage. All listed options are common consequences.

Floods cause soil erosion by washing away topsoil and lead to water pollution by carrying sewage, chemicals, and debris into water sources.

Cyclones often disrupt sanitation and water supply systems, creating conditions that facilitate the spread of infectious diseases like cholera or typhoid.

Natural disasters disrupt supply chains and infrastructure, leading to food scarcity, health hazards due to poor sanitation, and water scarcity through contamination.

Tsunami waves are characterized by extremely long wavelengths, often hundreds of kilometers, which allows them to carry massive amounts of energy across the ocean.

Natural disasters cause extensive environmental damage, including the destruction of habitats, loss of topsoil through erosion, and degradation of soil quality.

Landslides occur more frequently in areas with unstable slopes, poor soil strength, or existing erosion, as these factors reduce the slope's resistance to gravity.

Excessive rainfall leads to the accumulation of water beyond the capacity of drainage systems, resulting in floods.

Tsunamis are defined by their long wavelengths and, upon reaching shallow water, their significantly larger amplitudes compared to typical ocean waves.

Forest fires release large amounts of particulate matter, smoke, and greenhouse gases into the atmosphere, making them a significant source of air pollution.

Storms are meteorological phenomena driven by atmospheric pressure differences, where air moves from high-pressure areas to low-pressure areas.

Storms, characterized by high winds and falling debris, frequently damage power lines and infrastructure, leading to widespread electricity supply disruptions.

Forest fires destroy habitats, kill wildlife, and alter vegetation structures, directly and significantly impacting biodiversity.

The severity of damage caused by a cyclone is directly proportional to its intensity, which is measured by wind speed and barometric pressure.

Tornadoes can cause water contamination by damaging sewage systems, flooding wells, and washing pollutants into water supplies.

Tornadoes often cause electrical damage, gas leaks, and structural collapse, which frequently lead to fires in the aftermath.

Cyclones are complex weather systems influenced by sea surface temperature, air humidity, and wind speed, which all contribute to their formation and strength.

A cloudburst is a localized, extreme precipitation event that occurs over a short period, often leading to flash floods and accompanied by intense weather.

A flood is defined as an overflow of water onto land that is usually dry, typically caused by heavy rain, dam failure, or storm surges.

The seismic focus (or hypocenter) is the point inside the Earth where an earthquake rupture starts, while the epicenter is the point on the surface directly above it.

A cyclone is characterized by a low-pressure center around which air rotates in a spiral pattern due to the Coriolis effect.

Roadside villages are often built in low-lying areas or near drainage paths, making them highly vulnerable to flooding compared to deserts or mountain peaks.

• Earthquake is a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earth's crust and the sudden release of energy in the Earth's lithosphere that creates seismic waves.
• Tectonic plates are pieces of Earth's crust. Together with upper mantle, it is called the lithosphere.
  
• Earthquakes are caused due to the shift of the tectonic plates present on the crust of the earth.
  
• So, the correct answer is 'The shift of the tectonic plates present on the earth crust'.

Reforestation is a process of replanting trees in an area, reforestation is an effective way of checking floods, planting trees can reduce the height of flood by 20%.

• Earthquake is a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earth's crust and the sudden release of energy in the Earth's lithosphere that creates seismic waves.
• A seismograph, or seismometer, is an instrument used to detect and record earthquakes. Generally, it consists of a mass attached to a fixed base. During an earthquake, the base moves and the mass does not.
  
• Hence earthquakes recorded by a seismograph.
• So, the correct answer is 'By a seismograph'.

• A tsunami or tidal wave, also known as a seismic sea wave, is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake.
• A tsunami can be caused due to various reasons. Among them, the most destructive Tsunamis are caused by earthquakes 
  
• Hence a tsunami can be caused due to Underwater earthquake.
  
• So, the correct answer is 'Underwater earthquake'.

Earthquakes are caused by the sudden release of accumulated energy when tectonic plates, which have been locked or jammed, finally slip past each other. This release of stress generates seismic waves.

• A tsunami or tidal wave, also known as a seismic sea wave, is a series of waves in a water body caused by the displacement of a large volume of water, generally in an ocean or a large lake.
• Mangroves are forests of salt-tolerant trees and shrubs that grow in the shallow tidal waters of estuaries and coastal areas in tropical regions. Mangroves protect shorelines from damaging storm and hurricane winds and tsunami.
• A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Coral reefs provide protection to our coasts from the tsunami, storms, and floods.
  
• Hence Coral Reefs and Mangroves can act as natural barriers to control Tsunami.
• So, the correct answer is 'Both A and B'.

The Japanese word Tsunami is composed of 'tsu', meaning harbor, and 'nami', meaning wave. It literally translates to harbor wave.

The 2004 Indian Ocean earthquake and tsunami occurred on December 26, 2004, and is recognized as one of the deadliest natural disasters in recorded history.

Slip erosion is a common term used to describe the downward movement of soil and rock, which is scientifically known as a landslide.

Preventive measures for cyclones include advanced prediction technology, effective warning systems for coastal populations, and emergency response infrastructure to restore services.