Tectonic Hazards: Earthquakes & Volcanoes
Tectonic hazards, including earthquakes and volcanic eruptions, occur mainly along plate margins where convection currents and slab pull move the Earth's lithospheric plates. Studying constructive, destructive, conservative, and collision plate margins explains both the physical causes of hazards and how monitoring, prediction, protection, and planning reduce risk.
- Tectonic Plate
- A massive, irregularly shaped slab of solid rock that makes up the Earths lithosphere.
- Constructive Margin
- A plate boundary where two plates move apart, allowing magma to rise and form new crust.
- Destructive Margin
- A plate boundary where an oceanic plate subducts under a continental plate, causing friction, melting, and explosive volcanoes.
Tectonic Hazards: Earthquakes & Volcanoes: Flood Hydrographs, Plate Margins & Global Systems
Test how land use changes storm hydrograph lag times, compare plate boundaries, and inspect global atmospheric cells and the Demographic Transition Model.
Destructive Margin (e.g. Nazca Plate subducting under South American Plate)
Dense basaltic oceanic crust subducts beneath lighter continental crust into the mantle, forming a deep ocean trench (Peru-Chile Trench). Friction in the Benioff zone triggers powerful earthquakes, while flux melting of the subducting slab produces viscous, silica-rich andesitic magma that erupts violently from composite stratovolcanoes.
Key Concepts & Exam Definitions (5)
- Tectonic Plate
- A massive, irregularly shaped slab of solid rock that makes up the Earths lithosphere.
- Constructive Margin
- A plate boundary where two plates move apart, allowing magma to rise and form new crust.
- Destructive Margin
- A plate boundary where an oceanic plate subducts under a continental plate, causing friction, melting, and explosive volcanoes.
- Primary Effects
- The immediate damage caused directly by the hazard (e.g., collapsed buildings, ground shaking).
- Secondary Effects
- The knock-on impacts that happen later as a result of primary effects (e.g., tsunamis, disease, fires).
Quick-Fire Flashcards (5)
Click any card to check the answer, then mark it as Known to track your progress.
What is the point on the Earths surface directly above an earthquakes focus called?
What instrument is used to measure earthquakes?
What scale is used to measure the magnitude of an earthquake?
Name the process where one tectonic plate is forced under another.
What are the three P's of hazard management?
Exam-Style Questions & Mark Schemes (3)
Write or think through your answer first, then click Check Mark Scheme to see the exact points examiners award marks for.
- Q1
Describe the movement of plates at a conservative plate boundary.
Click “Check Mark Scheme” to compare your answer, Plates slide past each other in opposite directions, or in the same direction at different speeds.
- Q2
Give two primary effects of a volcanic eruption.
Click “Check Mark Scheme” to compare your answer, Lava flows destroying property; ash clouds burying crops and buildings.
- Q3
Explain one reason why an earthquake in an LIC (Low-Income Country) might have a higher death toll than in an HIC (High-Income Country).
Click “Check Mark Scheme” to compare your answer, LICs often have poor building infrastructure that cannot withstand shaking, and weaker emergency response systems.
Common Exam Questions (3)
What causes an earthquake?
An earthquake occurs when two tectonic plates moving past or toward each other become locked by friction. Stress builds up in the crust until the rock fractures along a fault line, releasing stored seismic energy in shockwaves from the focus.
What are the main types of plate boundaries?
There are four plate margins: constructive (plates move apart, forming shield volcanoes), destructive (dense oceanic crust subducts beneath continental crust, causing earthquakes and composite volcanoes), collision (two continental plates collide, forming fold mountains), and conservative (plates slide past each other, causing earthquakes).
Why do people live in tectonically active areas?
People live near volcanoes and fault lines because weathered volcanic ash produces fertile soils for farming, geothermal energy provides cheap electricity and heating, volcanic landscapes attract tourism jobs, and residents often have strong family ties or limited financial means to relocate.
Need more questions on Tectonic Hazards: Earthquakes & Volcanoes, or want to organise your own notes?
Type a specific exam question you are stuck on, pick one of the prompts below, or paste your class notes to build a custom set of flashcards and practice questions on this page.
Related study guides
Weather, Climate & Climate Change
Global atmospheric circulation transfers thermal energy from low latitudes (the Equator) toward the poles through the Hadley, Ferrel, and Polar cells, governing the world's climate zones and the distribution of tropical storms. This guide covers global circulation, hurricane formation, UK extreme weather, and natural vs human causes of climate change.
Rivers, Flooding & Coastal Landscapes
Rivers shape the land from source to mouth through the fluvial processes of erosion, transportation, and deposition. Understanding how river landforms (waterfalls, meanders, ox-bow lakes, and floodplains) develop and how physical and human factors affect storm hydrographs explains how engineers manage flood risk.