[Mission 2024] STATIC QUIZ, 5 March 2024 – Geography

Solution: a)

Only Statement 2 is correct.

Earth’s crust is made up of tectonic plates that are slowly moving, at about the same speed as a fingernail grows. Volcanoes typically occur where these plates either move away from each other or where one pushes beneath another. But volcanoes can also be in the middle of plates, as Hawaii’s volcanoes are in the Pacific Plate.

The crust and mantle that comprise the Pacific Plate cracks at different places as it moves northwestward. Beneath Hawaii, magma can move upward through the cracks to feed different volcanoes on the surface. The same thing happens at Haleakala, on Maui, which last erupted about 250 years ago.

Scientists hypothesize that the mantle is not made of uniform rock. Instead, differences in the type of mantle rock make it melt at different temperatures. Mantle rock is solid at some places, while it starts to melt at other places.

Hawaii is in the middle of an oceanic plate. In fact, it is the most isolated volcanic hot spot on Earth, far away from any plate boundary.

Oceanic magma is very different from continental magma. It has a different chemical composition and flows much more easily. So, the magma is less prone to clog volcanic vents on its ascent, which would ultimately lead to more explosive volcanism.

Solution: b)

Statement 2 is incorrect.

Meteors are usually fragments of comets. As they enter the Earth’s atmosphere at high speed, they burn up, creating a spectacular “shower”.

According to NASA, “Meteors come from leftover comet particles and bits from asteroids. When these objects come around the Sun, they leave a dusty trail behind them. Every year Earth passes through these debris trails, which allows the bits to collide with our atmosphere where they disintegrate to create fiery and colorful streaks in the sky.”

NASA describes the Geminids as “one of the best and most reliable annual meteor showers”.

The Geminids are unique because unlike most meteor showers, they originate not from a comet, but from an asteroid, the 3200 Phaethon. As the 3200 Phaethon moves close to the Sun while orbiting it, the rocks on its surface heat up and break off. When the Earth passes through the trail of this debris, the Geminids are caused.

And why are they called Geminids?

That comes from the constellation Gemini, from whose location in the sky the meteor shower appears to originate.

Solution: b)

Statement 3 is incorrect.

A warming planet is resulting in the loss of the Earth’s cryosphere — parts of the planet where water is permanently frozen such as glaciers and ice sheets, and this could be resurrecting trapped pathogens, giving rise to potential public health threats, find a new study.

Permafrost is any ground that remains completely frozen—32°F (0°C) or colder—for at least two years straight. These permanently frozen grounds are most common in regions with high mountains and in Earth’s higher latitudes—near the North and South Poles.

Permafrost covers large regions of the Earth. Almost a quarter of the land area in the Northern Hemisphere has permafrost underneath. Although the ground is frozen, permafrost regions are not always covered in snow.

Most permafrost is located in high latitudes (in and around the Arctic and Antarctic regions), but at lower latitudes alpine permafrost occurs at higher elevations.

It can also be located in the Southern Hemisphere, just on mountain tops. Permafrost frequently occurs in ground ice, but it also can be presented in non-porous bedrock. Permafrost is formed from ice holding all different sorts of soil, sand, and rock combination together.

There is approximately twice as much carbon in permafrost than is currently in the Earth’s atmosphere.

Solution: b)

Statement 1 is incorrect.

The gas in the magma of Hawaii’s volcanoes tends to escape, and so lava flows down the side of their mountains when they erupt. Hawaii’s volcanoes are called shield volcanoes because successive lava flows over hundreds of thousands of years build broad mountains that resemble the shape of a warrior’s shield.

Shield volcanos are also found in California and Idaho as well as Iceland and the Galapagos Islands. Alaska’s Wrangell-St. Elias National Park has eight shield volcanoes including Mount Wrangell. Volcanoes like Mount St. Helens are called composite or stratovolcanoes. Their steep, conical slopes are built by the eruption of viscous lava flows and rock, ash and gas. Japan’s Mount Fuji is another example of a composite volcano.

How do scientists monitor Mauna Loa?

Scientists use tiltmeters to track long-term changes in the tilting of the ground, helping them identify when the ground is swelling or deflating.

A rapid change in tilt can indicate when an eruption will occur. There’s also a thermal webcam at Mauna Loa’s summit that will identify the presence of heat. And satellite radar can keep track of ground swelling and deflation.

Solution: d)

Coronal Mass Ejections (CMEs) are large expulsions of plasma and magnetic field from the Sun’s corona. They can eject billions of tons of coronal material and carry an embedded magnetic field (frozen in flux) that is stronger than the background solar wind interplanetary magnetic field (IMF) strength. CMEs travel outward from the Sun at speeds ranging from slower than 250 kilometers per second (km/s) to as fast as near 3000 km/s.

The fastest Earth-directed CMEs can reach our planet in as little as 15-18 hours. Slower CMEs can take several days to arrive. They expand in size as they propagate away from the Sun and larger CMEs can reach a size comprising nearly a quarter of the space between Earth and the Sun by the time it reaches our planet.