Earth Science: Layers and Natural Disasters
37 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What layer of the Earth is composed of solid rock and serves as the surface layer?

  • Core
  • Lithosphere
  • Crust (correct)
  • Mantle

Which of the following statements about the thickness of the Earth's crust is correct?

  • Oceanic crust is thicker than continental crust.
  • Continental crust is thicker than oceanic crust. (correct)
  • Oceanic crust could be as thick as 60km.
  • The crust is the same thickness everywhere on Earth.

What is the Moho boundary?

  • The separation between oceanic and continental crust.
  • The transition between the outer core and the mantle.
  • The boundary between the crust and the asthenosphere.
  • The boundary between the mantle and the crust. (correct)

What primarily causes the movement of the continents?

<p>Convection currents in the mantle. (D)</p> Signup and view all the answers

What is the asthenosphere?

<p>A liquid layer of the upper mantle that flows. (A)</p> Signup and view all the answers

What shapes do hardened lava forms typically have?

<p>Steep and conical (C)</p> Signup and view all the answers

What are lahars primarily caused by?

<p>Mixing of pyroclastic flows with water (D)</p> Signup and view all the answers

Which of the following events can cause a tsunami?

<p>All of the above (D)</p> Signup and view all the answers

How does the speed and height of tsunami waves change near the coastline?

<p>They become higher and slower (C)</p> Signup and view all the answers

What is a primary characteristic of pyroclastic flows?

<p>They are composed of clouds of gases and ash (A)</p> Signup and view all the answers

What causes the inner core of the Earth to remain solid despite extremely high temperatures?

<p>High pressure from the weight of Earth (A)</p> Signup and view all the answers

Which type of boundary is characterized by plates moving toward one another?

<p>Convergent boundary (D)</p> Signup and view all the answers

What is the primary reason for the creation of new crust at divergent boundaries?

<p>Rising molten rock from the mantle (C)</p> Signup and view all the answers

Which layer of the Earth is both the thickest and hottest?

<p>Inner core (B)</p> Signup and view all the answers

What geological features are typically formed at convergent boundaries where oceanic plates collide?

<p>Ocean trenches (A)</p> Signup and view all the answers

Which property of the asthenosphere allows lithospheric plates to float and drift?

<p>Low viscosity (C)</p> Signup and view all the answers

Which of the following is NOT a feature associated with divergent boundaries?

<p>Subduction zones (B)</p> Signup and view all the answers

Which process is responsible for the movement of plates in plate tectonics?

<p>Convection currents in the mantle (C)</p> Signup and view all the answers

What is the primary composition of the Earth's inner core?

<p>Iron and nickel (C)</p> Signup and view all the answers

Which geological process can lead to the formation of high mountains?

<p>Subduction (C)</p> Signup and view all the answers

How does the density of oceanic crust compare to that of continental crust?

<p>Oceanic crust is more dense (D)</p> Signup and view all the answers

What is the primary reason for the occurrence of earthquakes along transform fault boundaries?

<p>Tectonic plate grinding past each other (C)</p> Signup and view all the answers

What was the name of the supercontinent that existed around 200 million years ago?

<p>Pangaea (D)</p> Signup and view all the answers

What geological feature is primarily associated with earthquakes occurring?

<p>Fault lines (B)</p> Signup and view all the answers

What term describes the point on the Earth's surface directly above where an earthquake originates?

<p>Epicenter (B)</p> Signup and view all the answers

Which type of seismic wave is the fastest and is recorded first on a seismograph?

<p>P wave (D)</p> Signup and view all the answers

What is the primary reason for the formation of magma within the Earth?

<p>Pressure from above rocks (C)</p> Signup and view all the answers

What type of volcano is characterized by gentle slopes and is primarily composed of basalt?

<p>Shield volcano (D)</p> Signup and view all the answers

What does the Richter Scale measure?

<p>Magnitude of earthquakes (B)</p> Signup and view all the answers

Which of the following is NOT a type of volcanic eruption?

<p>Hydrothermal explosion (D)</p> Signup and view all the answers

What is a secondary wave characterized by?

<p>Up and down movement and cannot pass through liquids (A)</p> Signup and view all the answers

Aftershocks are typically caused by what phenomenon?

<p>Sudden release of pressure from the main earthquake (D)</p> Signup and view all the answers

What drives the movement of magma towards the Earth's surface?

<p>Less density compared to surrounding rocks (A)</p> Signup and view all the answers

Which of the following terms refers to a volcano that has not erupted in human history?

<p>Extinct volcano (D)</p> Signup and view all the answers

What causes the trembling on the Earth's surface during an earthquake?

<p>Release of energy from the focus (D)</p> Signup and view all the answers

Which type of volcanic rock forms when lava cools rapidly?

<p>Igneous rock (D)</p> Signup and view all the answers

What geological phenomenon can lead to the creation of volcanic islands like those in Hawaii?

<p>Hotspots in the mantle (D)</p> Signup and view all the answers

Flashcards

Mantle

The layer of Earth below the crust that is about 2800km thick and contains convection currents.

Moho

The boundary between the crust and the mantle, where the composition of the Earth changes.

Asthenosphere

The liquid layer of the upper mantle that flows. It's where the Earth's plates float and move.

Why the outer mantle is melting

The heat coming from the Earth's core causes the rock in the outer 200km of the mantle to be close to its melting point.

Signup and view all the flashcards

Convection currents

Circular movements of heated rock within the mantle, driven by heat from the Earth's core.

Signup and view all the flashcards

Volcanic Cone

A cone-shaped mountain formed by layers of hardened lava, often with steep slopes.

Signup and view all the flashcards

Pyroclastic Flow

Fast-moving, deadly clouds of hot gas, ash, and volcanic rocks that travel away from a volcanic vent.

Signup and view all the flashcards

Lahar

Volcanic mudflows that occur when hot volcanic material mixes with water. They can occur during or even long after volcanic eruptions.

Signup and view all the flashcards

Tsunami

A giant wave caused by a sudden movement of a large volume of ocean water, often triggered by earthquakes or underwater landslides.

Signup and view all the flashcards

What causes a Tsunami?

The rapid rise or fall of a large area of the ocean floor, often triggered by earthquakes, volcanic eruptions, or landslides, can generate a tsunami.

Signup and view all the flashcards

Fault Lines

A deep crack in the Earth's crust where rock masses have moved past each other. These movements cause seismic activity, like earthquakes.

Signup and view all the flashcards

Focus

The point inside the Earth where an earthquake originates, often deep underground.

Signup and view all the flashcards

Epicenter

The point on the Earth's surface directly above the focus of an earthquake, where the strongest shaking typically occurs.

Signup and view all the flashcards

P-wave (Primary Wave)

A type of seismic wave that travels through solids, liquids, and gases, and is recorded first on a seismograph. This wave compresses and expands the rock it passes through.

Signup and view all the flashcards

S-wave (Secondary Wave)

A type of seismic wave that travels only through solids and is recorded second on a seismograph. This wave moves up and down, like ripples in water.

Signup and view all the flashcards

Aftershocks

Smaller earthquakes that occur after a major earthquake, often along the same fault line.

Signup and view all the flashcards

Volcano

An opening in the Earth's crust through which molten rock, ash, and gases erupt onto the surface.

Signup and view all the flashcards

Magma

Molten rock found beneath the Earth's surface. It is less dense than surrounding rock and rises towards the surface.

Signup and view all the flashcards

Volcanic Hotspot

An area in the Earth's mantle where magma is hotter, causing it to rise and create volcanoes.

Signup and view all the flashcards

Active Volcano

A volcano that has erupted in recent history and is likely to erupt again.

Signup and view all the flashcards

Dormant Volcano

A volcano that has not erupted in a very long time but may erupt in the future.

Signup and view all the flashcards

Extinct Volcano

A volcano that has not erupted in human history and is not expected to erupt in the future.

Signup and view all the flashcards

Shield Volcano

A type of volcano with gentle slopes, formed by layers of fluid basalt lava that flows easily.

Signup and view all the flashcards

Cinder Cone Volcano

A type of volcano formed by explosive eruptions of cinders and ash, creating a cone-shaped structure.

Signup and view all the flashcards

What is the Earth's core composed of?

The Earth's core is divided into a solid inner core and a liquid outer core, both primarily composed of iron and nickel.

Signup and view all the flashcards

Why is the inner core solid?

The pressure from the weight of Earth is so immense that it keeps the inner core solid, despite its high temperature.

Signup and view all the flashcards

What is Plate Tectonics?

The theory of Plate Tectonics explains the movement of the Earth's crust, which is divided into large plates that constantly shift.

Signup and view all the flashcards

Why do earthquakes and volcanoes occur?

Earthquakes and volcanoes are primarily caused by the movement and interactions of these tectonic plates at their boundaries.

Signup and view all the flashcards

What happens at Divergent boundaries?

Divergent boundaries occur when tectonic plates move apart, resulting in the creation of new crust at mid-ocean ridges.

Signup and view all the flashcards

What happens at Convergent boundaries?

Convergent boundaries occur when tectonic plates collide. The denser plate subducts beneath the lighter one, leading to volcanic activity and mountain formation.

Signup and view all the flashcards

What happens at Transform fault boundaries?

Transform fault boundaries occur when tectonic plates slide past each other horizontally, causing friction and earthquakes.

Signup and view all the flashcards

Compare the density and thickness of oceanic and continental crust. What is asthenosphere?

Oceanic crust is denser and thinner than continental crust. The asthenosphere is a partially molten layer in the upper mantle.

Signup and view all the flashcards

What is the Mid-Atlantic Ridge?

The Mid-Atlantic Ridge is a prime example of a divergent boundary, where new seafloor is created as plates move apart.

Signup and view all the flashcards

What are Rift valleys?

Rift valleys are examples of divergent boundaries on land, where the Earth's crust stretches and breaks apart.

Signup and view all the flashcards

What is an example of a convergent boundary involving oceanic and continental plates?

The Juan de Fuca plate subducts beneath the North American Plate at a convergent boundary, leading to volcanic activity in the Pacific Northwest.

Signup and view all the flashcards

What is an example of a convergent boundary involving two continental plates?

The Himalayan mountain ranges are a result of the collision of two continental plates, a classic example of a convergent boundary.

Signup and view all the flashcards

What is an example of a convergent boundary involving two oceanic plates?

The Mariana Trench is a deep ocean trench formed by the convergence of two oceanic plates.

Signup and view all the flashcards

What is an example of a transform fault boundary?

The San Andreas Fault in California is a famous transform fault boundary, where the Pacific plate slides past the North American plate, causing earthquakes.

Signup and view all the flashcards

What is Continental Drift?

The theory of Continental Drift suggests that the continents once formed a single supercontinent called Pangaea, which gradually broke apart over millions of years.

Signup and view all the flashcards

Study Notes

Earth's Layers

  • Crust: Solid rock, outermost layer, broken into plates (both major and minor). Oceanic crust is thinner (5 km) than continental crust (60 km). Boundary with the mantle is the Moho.

  • Mantle: Much thicker than the crust (2800 km), contains convection currents (heat circulation). The outer 200 km of the mantle is close to its melting point due to heat from the core, creating the liquid asthenosphere. Rock in the mantle flows, causing plate movement.

  • Core: Center of Earth, thickest and hottest layer (3470 km). Solid inner core and liquid outer core, primarily composed of iron and nickel. Outer core generates Earth's magnetic field. High pressure maintains inner core's solid state despite high temperature.

Plate Tectonics

  • Theory: Explains earthquake, volcano, and mountain formation. Continents are in continual motion due to stress at the surface from internal pressures.

  • Plate Boundaries: Where tectonic plates meet. Active regions for volcanoes and earthquakes.

    • Divergent: Plates move apart, creating new crust (e.g., mid-ocean ridges, rift valleys).
    • Convergent: Plates collide, leading to subduction (one plate moving under another), volcanic activity, and mountain ranges. (Oceanic-continental, Oceanic-oceanic, and Continental-continental).
    • Transform: Plates slide past each other, creating friction and earthquakes (e.g., San Andreas Fault).

Key Properties of Earth's Layers

Layer Thickness (km) Density (g/cm³) Temperature (°C) State of Matter Chemical Composition
Crust 5-70 2.7-3.0 ~0-1,000 Solid Silicates
Mantle ~2,900 3.3-5.7 ~1,000-3,700 Solid (flows slowly) Silicates rich in Fe, Mg
Outer Core ~2,300 9.9-12.2 ~4,000-6,000 Liquid Mostly iron (Fe) and nickel (Ni)
Inner Core ~1,220 ~12.8-13.1 ~5,000-7,000 Solid Mostly iron (Fe) and nickel (Ni)

Continental Drift

  • Pangaea: Ancient supercontinent, one large ocean.
  • Evidence for plate movement and continental drift: Jigsaw fit of continents, similar rocks and fossils across continents, glacial evidence in locations where glaciers would not be expected today, and fossil records.

Earthquakes

  • Causes: Sudden movement along fault lines (fractures in Earth's crust) from sudden release of stress. Occur primarily at plate boundaries.
  • Measuring Earthquakes: Seismometers are used to detect and record earthquake vibrations. Richter and Shindo scales describe earthquake magnitude.
  • Seismic Waves: P-waves (primary) are faster, compressional, and travel through solids, liquids, and gases; S-waves (secondary) are slower, move side-to-side, and cannot travel through liquids or gases.
  • Focus & Epicenter: Focus = point of initial movement; Epicenter = point on surface directly above focus.
  • Aftershocks: Smaller earthquakes after a main earthquake caused by adjustments in the fault lines.

Volcanoes

  • Formation: Divergent and convergent boundaries, and hotspots.
  • Magma vs. Lava: Magma is molten rock below the surface, lava is molten rock released above the surface.
  • Types of Eruptions: Different types of eruptions exist, with some violent and explosive, while others are more gentle and slow-flowing.
  • Types of Volcanic Rocks/Materials: Volcanic dust, ash, cinders, igneous rocks (basalt, pumice).
  • Cones/Crater/Hotspots: Layers of cooled lava accumulate to form cones. Hotspots are areas in the mantle where magma is hotter, which rises. Volcanoes erupt as material is released from an elevated magma chamber.
  • Types of Volcanoes: Active, dormant, and extinct volcanoes. Different subtypes (shield, cinder cone, composite).
  • Pyroclastic Flows & Lahars: Fast-moving clouds of hot volcanic gases, ashes, and volcanic bombs. Lahars = mixed flows of ash and water from a volcano.

Tsunamis

  • Causes: Often from earthquakes but can also be from volcanoes or landslides.
  • Movement: Higher waves near the shore when the water is shallow; Lower, faster speed in deep oceans.
  • Impact: Massive destructive force on coastlines.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Description

Test your knowledge on the Earth's layers, including the crust and asthenosphere, as well as natural disasters such as tsunamis, lahars, and pyroclastic flows. This quiz covers fundamental concepts in geology and earth science, providing a comprehensive overview of the Earth's structure and dynamics.

More Like This

Earth's Layers and Core
18 questions

Earth's Layers and Core

UnquestionableDialect avatar
UnquestionableDialect
Layers of the Earth Flashcards
50 questions

Layers of the Earth Flashcards

SustainableAntigorite1088 avatar
SustainableAntigorite1088
Earth's Layers Overview
10 questions

Earth's Layers Overview

VirtuousConflict avatar
VirtuousConflict
Plate Tectonics and Natural Processes (Study Guide)
25 questions

Plate Tectonics and Natural Processes (Study Guide)

YoungMarigold avatar
YoungMarigold
Use Quizgecko on...
Browser
Open
Browser
Browser