Natural Disasters

Vocabulary flashcards covering the key terms, physical principles, and disaster mechanisms described in Chapter 18: Natural Disasters.

Natural Disaster

The losses brought about on humans, animals, and property by a natural process without the interference of man.

Cyclone

A severe atmospheric whirl developed from a depression when local atmospheric pressure near the Earth's surface drops significantly below surrounding pressure over warm oceanic waters.

Eye of a Cyclone

The central calm region of a whirlwind spreading $30\text{ - }60\,\text{km}$ from the center, characterized by low wind, an absence of rain and clouds, and appearing as a black circle in satellite photographs.

Eye Wall

The cylindrical cluster of clouds arranged around the eye of a cyclone where heavy rains and fast-blowing winds occur.

Tropical Cyclone

The name given to cyclones formed in the North and South Asian oceans.

Typhoon

The name given to cyclones generated in the Northern Pacific Ocean.

Hurricane

The term used for cyclones produced in the North Atlantic Ocean.

Earthquake

A jolt or shoulder-like movement of the Earth's surface caused by the sudden release of energy stored within the Earth's crust.

Earth Tremor

A less violent earthquake caused by the release of energy stored in the Earth's crust.

Internal Structure of the Earth

The concentric physical organization of the Earth, consisting of the outermost crust, the middle mantle (upper and lower mantle), and the central core (outer and inner core).

Tectonic Plates

Rigid slabs of rock that compose the Earth's crust, which move relative to one another atop the semi-solid magma of the upper mantle.

Divergent Border

A boundary where two tectonic plates move away from each other, allowing magma from the upper mantle to rise and create new crust (e.g., the Mid Atlantic Ridge).

Convergent Border

A boundary where two tectonic plates collide and one plate moves underneath the other, often forming volcanoes (e.g., Saint Helen's mount).

Slip Border

A boundary where two tectonic plates slide past each other while in contact, accumulating stress that can cause violent earthquakes upon release (e.g., Saint Andrea's fault).

Focus

The subterranean point of rock breakage where stored energy is released, initiating an earthquake.

Epicenter

The point on the surface of the Earth located directly above the focus of an earthquake.

Seismic Waves

Waves that convey energy radiating outward in all directions from the focus of an earthquake, travelling through the Earth's interior (body waves) and along its surface (surface waves).

Seismometer

An instrument installed at various points on Earth to measure the strength of seismic waves.

Seismograph

An apparatus that automatically records information and signals related to seismic waves, producing seismograms.

Richter Scale

A quantitative scale introduced by Charles F. Richter in 1953 to classify earthquake magnitude based on seismographic data and observable destruction.

Pacific Ring of Fire

The borderland perimeter of the Pacific tectonic plate where the majority of the world's most severe earthquakes and volcanic eruptions occur.

Tsunami

A devastating series of sea waves caused by the vertical displacement of ocean water, primarily triggered by undersea earthquakes, seabed volcanic eruptions, submarine landslides, or meteorite impacts.

Wavelength

The horizontal distance measured between two successive crests or two successive troughs of a wave.

Amplitude

The vertical height measured from the undisturbed equilibrium midpoint of a wave to its crest.

Wild Fire

A fast-moving, high-temperature column of fire that sweeps through dry forests or jungles due to natural factors such as lightning or through deliberate/accidental human actions.

Global Warming

The sustained increase in the world's average surface temperature over the past 100 years, strongly linked to an increase in the frequency of natural disasters.

Greenhouse Effect

The process where atmospheric gases like carbon dioxide and water vapour absorb and retain part of the heat released from the Earth, maintaining thermal warmth necessary for life.