Test: Natural Calamities - 2 - Class 5 MCQ

Earthquakes are caused by the movement and interaction of tectonic plates, which are large sections of the Earth's crust that float on the semi-fluid asthenosphere beneath them. When these plates collide, move apart, or slide past each other, they create stress and build up energy along faults and fractures. When the accumulated energy is released suddenly, it results in seismic waves, causing an earthquake.

Tsunamis are giant sea waves that are primarily triggered by underwater earthquakes. When a powerful earthquake occurs beneath the ocean floor, it can displace a large volume of water, creating a series of waves that travel across the ocean at high speeds. These waves can grow in height as they approach shallower coastal areas, leading to devastating impacts when they reach the shore.

Active volcanoes are those that have erupted recently and are expected to erupt again. These volcanoes frequently show signs of volcanic activity, such as lava flows, ash emissions, and gas releases. Unlike dormant or extinct volcanoes, active volcanoes are in a state of constant change and have the potential to erupt in the future.

The word "tsunami" means "harbour waves" in Japanese. So (A) is the right answer

Tsunamis and cyclones are natural disasters that can have significant impacts on the environment.

• They often lead to floods due to heavy rainfall and rising sea levels.
• They do not cause droughts or earthquakes.

Therefore, the most likely impact of tsunamis and cyclones is flooding.

Excessive rainfall can lead to flooding. When an area receives more rain than the natural drainage system can handle, rivers, streams, and other water bodies overflow their banks, causing flooding in nearby regions. Floods can result in significant damage to properties, infrastructure, and even loss of lives.

Dormant volcanoes have not erupted for a long time but might erupt in the future. These volcanoes are not currently active but still pose a potential risk.

• Dormant volcanoes can remain inactive for hundreds to thousands of years.
• They have a history of eruptions and are not considered extinct.
• Monitoring is essential to predict any possible future eruptions.

During a tsunami, it is crucial to avoid activities that can increase the risk or impact of the event. One such activity is:

• Cutting down mangroves: Mangroves act as natural barriers against waves and storm surges. Removing them can increase coastal vulnerability.

Instead, focus on actions that enhance safety and preparedness:

• Ensure the controlled usage of rations to maintain supplies during the aftermath.
• Set up special alarms to alert communities of impending tsunamis.
• Go to higher ground as a precautionary measure to avoid flooding.

The correct answer is Natural Disaster.

A natural disaster refers to damage or destruction caused by natural forces. Examples include:

• Earthquakes - Sudden shaking of the ground.
• Floods - Overflow of water causing widespread damage.
• Hurricanes - Strong winds and heavy rain.

These events often lead to significant human and environmental impact.

Scientists who study earthquakes are called seismologists.

• Seismologists research and analyse the causes and effects of earthquakes.
• They use instruments like seismographs to measure ground movements.
• Their work helps predict future earthquakes and mitigate potential damage.