Geological Natural Disasters
Earthquakes and volcanic eruptions are overwhelmingly concentrated along these, where tectonic plates meet.
What are plate boundaries?
This gas, released in large quantities during explosive volcanic eruptions, forms aerosols in the atmosphere that reflect sunlight and cause short-term global cooling.
What is sulphur dioxide (SO2)?
This technology measures ground vibrations and is the primary tool for detecting and locating earthquake activity and monitoring volcanic tremor before eruptions.
What is a seismometer (seismograph)?
Gases like carbon dioxide, methane, and water vapour trap outgoing heat in the atmosphere, warming the Earth's surface in this natural process.
What is the (natural) greenhouse effect?
Microscopic plant particles, preserved in sedimentary rock, can be identified by species and used to reconstruct past climate conditions.
What are pollen grains?
This term describes a volcanic eruption that produces relatively gentle, flowing lava rather than violent explosions, typically associated with low-viscosity basaltic magma.
What is an effusive eruption?
This 1991 eruption is a well-studied example of a major volcanic event that cooled global temperatures by about 0.5°C for roughly a year.
What is the eruption of Mount Pinatubo?
This instrument measures tiny deformations in rock, allowing scientists to detect the slow build-up of pressure along a fault line before an earthquake occurs.
What is a strain meter?
Operating over hundreds of millions of years, this process is one of the slowest drivers of natural climate change, altering ocean circulation and CO2 levels.
What is the plate tectonic supercycle?
A shift from rock types like coal (formed in wet, swampy conditions) to rock types like evaporites (formed in dry conditions) within a sequence can indicate this long-term change.
What is climate change (a change in climate conditions)?
This term describes a violent, gas-driven volcanic eruption that ejects ash, rock, and pyroclastic material, typically associated with high-viscosity magma at convergent boundaries.
What is an explosive eruption?
Beyond its cooling effect on climate, Pinatubo's ash fall damaged crops and vegetation, and its impact on rainfall patterns disrupted this large-scale natural system that living things depend on.
What is the biosphere?
Some researchers have investigated unusual changes in this as a possible, though scientifically contested, precursor signal before earthquakes.
What is animal behaviour?
This massive series of volcanic eruptions in present-day India, occurring around 66 million years ago, released huge volumes of CO2 and is linked to significant climate disruption.
What are the Deccan Traps?
Certain species' remains, including microscopic ones, in rock layers can indicate past temperature and environmental conditions, since many organisms are sensitive to specific climate ranges.
What are fossils and microfossils?
This area of increasingly deep earthquake foci, found where an oceanic plate subducts beneath another plate, marks the path of the descending slab.
What is the Benioff (Wadati-Benioff) zone?
Unlike explosive eruptions, this type of eruption releases far less ash and aerosols into the upper atmosphere, generally causing more localised rather than global environmental impact.
What is an effusive eruption?
This method involves using GPS and satellite radar to detect subtle swelling or deformation of a volcano's slopes, which can indicate rising magma before an eruption.
What is ground-movement (deformation) monitoring?
This large series of volcanic eruptions in present-day Russia, occurring around 252 million years ago, is linked to the Permian-Triassic mass extinction event.
What are the Siberian Traps?
This dating technique compares the ratio of different atomic forms of the same element, such as oxygen-18 to oxygen-16, in rocks and deep-sea sediments to infer past temperatures.
What is isotope (ratio) analysis?
The region where tectonic plates move apart, earthquakes are typically shallow-focus, occurring near the surface.
What is a divergent boundary?
This type of severe weather event, caused by strong updrafts within storm clouds carrying water droplets high enough to freeze, can flatten crops and damage ecosystems on a local scale.
What is a hailstorm?
Meteorologists track changes in temperature and this atmospheric measurement, which typically drops significantly as an east coast low intensifies.
What is (atmospheric) pressure?
Cyclical variations in Earth's orbital eccentricity, axial tilt, and precession, which occur over tens to hundreds of thousands of years and influence long-term climate patterns.
What are Milankovitch cycles?
Extracted from places like Antarctica and Greenland, these cylindrical samples contain trapped gas bubbles and oxygen isotopes that provide a direct record of past atmospheric composition and temperature.
What are ice cores?
This point inside the Earth, where an earthquake's energy is released, contrasts with the epicentre, which is directly above it on the surface.
What is the focus (hypocentre)?
This East Australian weather system, an intense low-pressure system that forms off the NSW coast, can bring heavy rainfall, flooding, and coastal erosion.
What is an east coast low?
These regulations dictate structural standards, such as flexible foundations and reinforced materials, designed to help buildings withstand seismic activity.
What are building codes?
This element of Earth's orbit changes shape from more circular to more elliptical over a cycle of roughly 100,000 years, affecting the intensity of seasons.
What is eccentricity?
This technique uses the width and characteristics of annual growth rings in trees to determine past climate conditions, such as rainfall and temperature.
What is dendrochronology?
A large earthquake with its focus under the ocean floor can displace huge volumes of water, generating this fast-moving, destructive ocean wave.
What is a tsunami?
This climatic phenomenon involves a prolonged period of below-average rainfall and can increase the risk and severity of both bushfires and landslides.
What is a drought?
These use sensors and communication networks to alert communities in advance of hazards, allowing time for evacuation before events such as tsunamis or volcanic eruptions.
What are early-warning (disaster warning) systems?
Changes to these global pathways, which redistribute heat around the planet, can occur over decades to centuries and significantly influence regional and global climate.
What are ocean currents (ocean circulation)?
In Australia, these sites depict now-extinct megafauna and environments that no longer exist locally, providing cultural and visual evidence of past climates and ecosystems.
What are Aboriginal art (rock art) sites?
This volcanic hazard is a fast-moving mixture of volcanic ash, debris, and water (often from melting ice or heavy rain) that flows down a volcano's slopes like a slurry.
What is a lahar?
Land clearing, poor water management, and increased ignition sources are all examples of how this factor can increase the frequency and severity of natural disasters such as floods, bushfires, and landslides.
What is human activity?
Beyond physical technology, this strategy, evacuation routes, warning signs, and emergency procedures, is considered one of the most effective tools for reducing casualties from natural disasters.
What is (public) education?
This specific ocean and atmospheric circulation pattern, driven by the sinking of cold, salty water in the North Atlantic, helps regulate climate across Europe and beyond.
What is the thermohaline circulation (or Atlantic Meridional Overturning Circulation/AMOC)?
Isotope ratios in these slow-growing formations in caves and the ocean provide a detailed, layer-by-layer record of past climate conditions.
What are stalagmites, stalactites, and corals?