Geology and Earth Structure

A subcontinent is a large landmass that is smaller than a continent but is geographically separated from the rest of the continent by physical barriers like mountains. The Indian subcontinent is a prime example, separated from the rest of Asia by the Himalayas.

Subterranean is derived from 'sub' (under) and 'terra' (earth), meaning underground. The other words do not share this definition.

A caldera is a large volcanic crater formed by a major eruption leading to the collapse of the mouth of the volcano. It is distinct from other geological features like faults or hot spots.

An aftershock is a smaller earthquake that follows the main shock of a larger earthquake. They occur in the same region as the primary event.

Geothermal activity refers to the heating of underground water by magma. This process is responsible for features like geysers and hot springs.

A hot spot is an area in the mantle from which heat rises as a thermal plume from deep in the Earth. This heat can melt the crust to form volcanoes even away from plate boundaries.

The Ring of Fire is a major area in the basin of the Pacific Ocean where many earthquakes and volcanic eruptions occur. It is characterized by a horseshoe shape.

A seismogram is the visual record produced by a seismograph. It displays the amplitude and duration of seismic waves.

A tsunami is a series of large ocean waves caused by an underwater earthquake, landslide, or volcanic eruption. They can travel vast distances across the ocean.

The epicenter is the point on the Earth's surface directly above the focus, which is where the earthquake originates.

The focus (or hypocenter) is the point within the Earth where the earthquake rupture starts. It is located beneath the surface.

Seismic waves are the vibrations that travel through the Earth carrying the energy released by an earthquake. They are detected by seismographs.

A syncline is a fold in rock layers that is concave upward, forming a trough or downward fold. It is caused by compressional stress.

An anticline is a fold in rock layers that is convex upward, forming an arch-like shape. It is caused by compressional stress.

A strike-slip fault is a type of fault where the rocks on either side move horizontally past each other, with little to no vertical movement.