Daily Current Affairs Quiz: September 16, 2025

Answer: C [Lava tubes in basaltic flows]
Explanation:

A: Exfoliation domes are formed by the physical weathering process of pressure release, where outer layers of rock peel away due to reduced pressure. This is an exogenic process.

B: Talus slopes are accumulations of rock fragments at the base of cliffs, formed by weathering and rockfalls, driven by gravity and external forces.

C: (Correct Option) Lava tubes are formed during volcanic eruptions as molten lava flows and cools, creating hollow tubes. This is a result of volcanic activity, an endogenic process, not primarily related to weathering.

D: Honeycomb weathering is a type of chemical weathering where differential weathering creates small cavities and pits in rock surfaces, especially in sandstone, primarily due to salt crystal growth.

Answer: C [Both 1 and 2]
Explanation:

Statement 1 is Correct: Ojos del Salado is the highest active volcano in the world. It rises to 6,893 metres (22,615 ft) above sea level. Located in the Andes mountain range, it is higher than all other known volcanoes. It also contains the world’s highest permanent crater lake at about 6,390 m.

Statement 2 is Correct: Geographically, Ojos del Salado lies on the border of Chile and Argentina. The western slopes belong to Chile (Atacama region), and the eastern slopes to Argentina (Catamarca province). It is classified as an active stratovolcano, with its last recorded eruption in the 14th century, though minor fumarolic activity continues today.

Answer: B [2 and 3 only]
Explanation:

Statement 1 is incorrect: Yardangs are formed parallel, not perpendicular, to the prevailing wind direction.  The wind sculpts these elongated ridges over time.

Statement 2 is correct:  Cirques are formed by glacial erosion, and as glaciers carve deeper valleys, tributary glaciers often create hanging valleys that enter the main valley at a higher elevation.

Statement 3 is correct: Stalagmites grow upwards from the cave floor, formed by the dripping of mineral-rich water, the same process that forms stalactites hanging from the ceiling.

Statement 4 is incorrect: Lateral moraines are deposited along the sides of a glacier, not at the snout. Terminal moraines mark the glacier’s furthest extent.

Statement 5 is incorrect: Arcuate deltas, like the Nile, are significantly influenced by wave action, which redistributes the deposited sediment.  They are wave-dominated deltas, not solely fluvial.

Answer: C [Only three]
Explanation:

Statement 1 is correct: The epicenter is indeed the point on the Earth’s surface directly above the focus of an earthquake.

Statement 2 is incorrect: A volcano that has not erupted in the past 10,000 years but is expected to erupt again is considered dormant, not extinct.

Statement 3 is correct: The Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur.

Statement 4 is correct: Most earthquakes happen along the edges of the Earth’s tectonic plates.

Answer: C [Only three]
Explanation:

Statement 1 is Correct: The core-mantle boundary (CMB) is indeed located approximately 2,900 kilometers below the Earth’s surface. This depth is determined by studying the behavior of seismic waves as they pass through the Earth.

Statement 2 is Correct: The CMB separates the Earth’s solid silicate mantle from the liquid iron-nickel outer core. This difference in composition and physical state has significant implications for the Earth’s magnetic field and plate tectonics.

Statement 3 is Incorrect: Seismic waves actually slow down as they cross the core-mantle boundary. This is primarily due to the change in density and rigidity between the solid mantle and the liquid outer core. The presence of post-perovskite, a high-pressure mineral, in the lowermost mantle does not cause seismic waves to travel faster at the CMB.

Statement 4 is Correct: The D” layer, a heterogeneous region just above the CMB, exhibits unusual seismic wave behavior, suggesting variations in temperature, composition, and possibly even the presence of partial melt. Studying this layer provides valuable clues about the dynamics and evolution of the Earth’s deep interior.