Lecture 1: Natural Disasters: Overview, Characteristics, and Global Impact

A set of Q&A flashcards covering key concepts from Chapters 1–9, including how disasters are classified, the differences between hazard/disaster/catastrophe, recurrence intervals, magnitude, and regional patterns of natural hazards.

Where do hurricane tracks predominantly occur in the United States?

Along the East Coast and Gulf/Southern coast

—i.e., the eastern half of the U.S.

Where are weather-type (atmospheric) disasters concentrated compared to geologic-type disasters?

Weather-type disasters are concentrated in the eastern half of the U.S., while geologic-type disasters are concentrated in the western half.

What is Tornado Alley?

The central U.S. Great Plains region with a high frequency of tornadoes.

Name the big four tectonic/geologic disaster types.

Earthquakes, volcanic eruptions, landslides, and tsunamis.

Which is the largest storm system on Earth?

A hurricane, which is the biggest cyclone (cyclones are named differently in some basins, e.g., Indian Ocean uses ‘cyclone’).

What does peak ground acceleration (PGA) measure?

The maximum ground acceleration used as a measure of earthquake hazard.

What is a natural event?

Energy release by the Earth.

What is a natural hazard?

A natural event posing a threat to humans or property.

What is a natural disaster?

A hazard that is actualized causing death or destruction.

What is a natural catastrophe?

A natural disaster taken to great proportions (rare).

What is meant by a catastrophe in this course?

A natural disaster taken to great proportions; a very rare, extreme event.

What geologic feature can reverse a major river’s course, illustrating intraplate earthquakes?

The New Madrid Fault Zone (historic earthquakes in the central U.S. that altered the Mississippi River).

Where are faults most concentrated and why?

On the western margins of continents; due to plate boundaries and tectonic activity.

What is a plate boundary?

A location where two or more tectonic plates meet.

Which fault is used in class as the example for a ~200-year recurrence interval for a magnitude ~7.8 earthquake?

The Southern San Andreas Fault.

What is a recurrence interval?

The time between earthquakes of the same size; the reciprocal of frequency.

What is the typical duration of an earthquake?

Seconds to minutes.

Define areal (or aerial) extent in natural disasters.

The geographic area affected by the event.

Why have Asia and the Middle East historically suffered high earthquake death tolls?

High population density and poorer building construction/earthquake codes.

Why are disasters in industrialized nations often costly but not always deadly?

More property and infrastructure to lose; better building codes and evacuations reduce deaths.

What are the two broad categories of natural disasters by event type?

Geologic (tectonic) and atmospheric (weather) events.

What three natural events top the list of deadliest disasters historically, and where do they commonly occur?

Earthquakes, floods, and cyclones/hurricanes; most deadly in Asia and the Middle East due to population density and vulnerability.

What does the map of peak ground acceleration (PGA) illustrate?

Earthquake hazard, showing expected ground shaking intensity

—especially along west margins.

What is the difference between magnitude and energy release in disasters?

Magnitude indicates the energy released by the event; larger magnitude generally means more energy released. Specifically for earthquakes, the magnitude scale is logarithmic, meaning each whole number increase in magnitude represents approximately a 32-fold increase in the energy released.

How long does a hurricane last?

Usually days to about a week, as it moves and weakens inland.

Where are volcanoes especially noted, besides the West Coast?

Pacific Northwest; Hawaii; Alaska; volcanic regions along plate boundaries.

What is the relationship between recurrence interval and frequency?

Recurrence interval is the time between same-sized events; frequency is the number of events per time; they are reciprocals.

What is the primary energy source for hurricanes?

Warm ocean water (>26.5circC>26.5circC) and the latent heat released during condensation of water vapor.This energy drives the storm's strength and intensity.

What is the difference between weather and climate?

Weather describes atmospheric conditions over short periods, while climate describes average atmospheric conditions and patterns over long periods.