Hazards, Weather, and Climate Change

Natural hazard

A natural event that can cause damage, destruction, and death.

Hazard risk

The vulnerability of people or property to a natural hazard, influenced by factors such as magnitude, location, time of day, wealth, education, frequency, natural factors, and population density.

Oceanic crust

A type of tectonic crust that is younger, denser, thinner, and capable of sinking into the mantle.

Continental crust

A type of tectonic crust that is older, less dense, thicker, and cannot sink into the mantle.

Convection current

A circular movement in the mantle where magma heated by the inner core becomes less dense and rises, cools near the crust, becomes denser, and sinks back down, driving continental drift.

Earthquake

A sudden and violent period of ground shaking caused by the sudden release of pressure built up along tectonic plate margins.

Richter scale

A logarithmic scale from $1$ to $10$ measuring the size of seismic waves, where an increase of one whole number indicates a $10\times$ larger earthquake.

Moment Magnitude Scale

A logarithmic scale from $1$ to $10$ that measures the total energy released and the extent of movement along a fault during an earthquake.

Constructive plate boundary

A boundary where two tectonic plates move away from each other, allowing magma to rise, cool, and solidify into shield volcanoes while producing gentle earthquakes (e.g., North American and Eurasian plates forming Iceland).

Conservative plate boundary

A boundary where two plates slide past each other in opposite directions or at different speeds; friction causes them to lock until pressure releases violently as an earthquake (e.g., Pacific and North American plates).

Destructive subduction plate boundary

A plate margin where a denser oceanic plate moves toward and sinks beneath a continental plate, melting into the mantle to produce magma for composite volcanoes, fold mountains, and earthquakes (e.g., Nazca and South American plates).

Destructive collision plate boundary

A plate margin where two continental plates of equal density push into each other, folding the crust upward into fold mountains and releasing seismic waves as earthquakes without volcanic activity (e.g., Indo-Australian and Eurasian plates forming the Himalayas).

Volcano monitoring

The remote detection of volcanic warning signs, such as escaping gases, ground surface bulging, and rising groundwater temperatures.

Earthquake protection design

Structural engineering methods to prevent building collapse, including deep foundations, rubber shock absorbers, counter-weights, and shatterproof windows.

Global atmospheric circulation (GAC)