tectonics theory

Convergent Boundary (destructive subduction)

Oceanic crust meets continental crust, causing the denser oceanic crust to dive into the magma chambers, leading to volcanic activity.

Convergent Boundary (continental collision)

Two continental plates collide, causing the land between to buckle and rise, forming fold mountains.

Divergent Boundary

Plates move apart, allowing magma from the mantle to rise and create new crust; this can cause earthquakes and form shield volcanoes.

Conservative Boundary

Two plates slide against each other along a fault, causing friction that leads to pressure build-up and sudden earthquakes.

Composite Volcano

Characterized by steep, triangular sides and a crater on top, consisting of acidic lava that is thick and leads to violent eruptions.

Shield Volcano

Gentle-sided volcano with basaltic lava that flows easily, resulting in less explosive activity and destruction.

Hotspots

Volcanoes formed from fixed plumes of granitic lava that erupts explosively and are typically round in shape.

Lava Flows

Basalt fissure eruptions that can move at over 50 km/h and spread tens of kilometers from their source.

Pyroclastic Flow

A mixture of hot rock fragments, lava, and ash that can move at high speeds and extend up to 40 km from a volcano.

Ash and Tephra Fall

Volcanic ash that can cause irritation, damage vehicles and buildings, and disrupt water and electrical systems.

Volcanic Gases

Invisible gases emitted by volcanoes that can pose health hazards and affect climate.

Lahars

Volcanic ash mixed with water that creates a dense, slurry flow that can move rapidly downslope.

Volcanic Landslides

Gravity-driven slides of volcanic material, often occurring during eruptions or due to rainfall.

Tsunamis

Large waves generated by explosive volcanic eruptions or submarine caldera collapse.

Earthquake

Vibrations caused by earth movements at plate boundaries and major fault lines.

Focus

The point at which rock moves during an earthquake, resulting in seismic waves.

Epicenter

The point directly above the focus on the Earth's surface, experiencing the worst earthquake effects.

Deep Focus Earthquake

Occurs 70-700 km below the surface, causing powerful seismic waves that affect a small area.

Shallow Focus Earthquake

Occurs at less than 70 km, causing damage over a large area due to horizontally spreading seismic waves.

Moment Magnitude Scale

A logarithmic scale measuring the amount of energy released in an earthquake, where each level is ten times more powerful.

Earthquake Preparedness: Practice Drills

Training that teaches people to respond quickly during an earthquake, improving reaction time and safety awareness.

Emergency Kits

Collections of essential items needed immediately after an earthquake to ensure survival during service disruptions.

Public Education and Training

Programs that inform people about earthquake risks and safe actions to minimize injuries and loss of life.

Earthquake-resistant Building Design

Engineering methods to help buildings absorb seismic shaking and prevent collapse.

Land-use Planning

Avoiding building in hazardous areas to reduce earthquake risk.

Retrofitting Old Buildings

Upgrading structures built before modern safety standards to enhance their earthquake resilience.

Historical Seismic Records

Analysis of past earthquakes to identify patterns and estimate future quake likelihood.

GPS & Plate Motion Monitoring

Using GPS to detect how tectonic plates move and build up stress along faults.

Foreshocks

Small earthquakes that sometimes precede larger quakes but are often unreliable indicators.

Ground Deformation

Measurement of changes in the Earth’s surface caused by stress accumulation, indicating potential earthquake locations.

Early Warning Systems

Technologies that detect seismic waves and send alerts before strong shaking occurs.

Experimental / Unreliable Methods

Unconventional indicators of earthquakes, such as animal behavior and gas emissions, which are not scientifically reliable.