What is a tectonic hazard?
A tectonic hazard is a natural event caused by the movement of tectonic plates, which can result in disasters such as earthquakes, volcanic eruptions, and tsunamis.
Examples of tectonic hazards include earthquakes, volcanic eruptions, and tsunamis.
Where do earthquakes tend to occur?
Earthquakes tend to occur in distinct zones at the edges of tectonic plates, known as plate boundaries.
Intraplate earthquakes can also occur in regions like the Great Rift Valley and Tibet.
What influences the magnitude of an earthquake?
The magnitude of an earthquake is influenced by the type of plate boundary.
Examples include convergent and divergent boundaries.
What is the distribution of active volcanoes?
Most active volcanoes (about 75%) occur around the ‘Ring of Fire’ surrounding the Pacific Ocean, at convergent and divergent plate boundaries, and at hot spots.
An example of a hot spot is Hawaii.
How do tsunamis primarily form?
Tsunamis primarily form along convergent plate boundaries due to undersea earthquakes caused by subduction.
High-risk areas include Japan and Indonesia.
What is mantle convection?
Mantle convection is the process by which heat from the Earth’s core causes the movement of semi-solid rock within the asthenosphere, driving tectonic plate movement.
This process creates convection currents.
What is slab pull?
Slab pull is the dominant force in tectonic plate movement, occurring when dense oceanic plates sink into the mantle at subduction zones, pulling the rest of the plate with them.
Ridge push is another force, occurring at mid-ocean ridges.
What is the significance of paleomagnetism?
Paleomagnetism is the study of changes in the Earth’s magnetic field recorded in rocks, providing evidence for seafloor spreading and plate tectonics.
It shows symmetrical bands of normal and reversed polarity in rocks.
What are constructive plate margins?
Constructive plate margins are where two tectonic plates move apart, allowing magma to rise and form new crust, creating mid-ocean ridges or rift valleys.
Examples include the Mid-Atlantic Ridge.
What happens at destructive plate margins?
Destructive plate margins occur where two plates collide, leading to subduction, deep ocean trenches, and explosive volcanic activity.
An example is the Andes mountain range.
What are the primary hazards of earthquakes?
Primary hazards of earthquakes include:
* Crustal fracturing
* Ground shaking
* Liquefaction
* Landslides
* Tsunamis
What are the secondary hazards of volcanoes?
Secondary hazards of volcanoes include:
* Ash falls
* Gas eruptions
* Lahars
* Jökulhlaups
What is the definition of a fault?
A fault is a fracture or zone of fractures between two blocks of rock, which can lead to earthquakes.
Faults can vary in size and activity.
What is the difference between the hypocenter and epicenter of an earthquake?
The hypocenter is the point within the Earth where an earthquake rupture starts, while the epicenter is the point directly above it on the Earth’s surface.
These terms are crucial for understanding earthquake impacts.
What causes the explosive nature of some volcanic eruptions?
The explosive nature of volcanic eruptions is influenced by magma viscosity and gas content, with high-viscosity magma trapping gases and leading to explosive eruptions.
Low-viscosity magma typically results in gentler eruptions.
What is the Wadati-Benioff zone?
The Wadati-Benioff zone is a region of seismicity corresponding with the subduction of an oceanic plate beneath another plate, where earthquakes can occur at varying depths.
It is crucial for understanding earthquake depth and magnitude.
What is a primary hazard?
A primary hazard is a direct result of a tectonic event, such as ground shaking during an earthquake.
Examples include crustal fracturing and tsunamis.
What is a secondary hazard?
A secondary hazard is an indirect result of a primary hazard, such as landslides triggered by ground shaking.
Other examples include ash falls from volcanic eruptions.
What was the magnitude of the 2004 Indian Ocean earthquake?
The magnitude of the 2004 Indian Ocean earthquake was between 9.1 and 9.3.
This earthquake triggered one of the deadliest tsunamis in history.
What were the impacts of the 2004 Indian Ocean tsunami?
The impacts included:
* Over 230,000 deaths
* 1.7 million people displaced
* Economic devastation in fishing and tourism sectors
* Environmental damage including saltwater contamination
Fill in the blank: The _______ is the solid inner layer of the Earth composed mostly of iron and nickel.
inner core
Fill in the blank: The _______ is the semi-molten part of the upper mantle that allows plate movement.
asthenosphere
Which countries were among the hardest hit by the 2004 Indian Ocean tsunami?
Indonesia, Sri Lanka, India, Thailand
These countries faced significant devastation and loss of life due to the tsunami.
How many people were killed in the 2004 Indian Ocean tsunami?
More than 230,000 people
The tsunami caused one of the deadliest natural disasters in history.
