Activity; Volcanoes and Earthquakes
Volcanoes
Volcanoes are cracks that open in the Earth’s crust through which different materials from the Earth’s interior are expelled. These cracks form when two tectonic plates collide or due to the action of the Earth’s internal forces. That is why there are more volcanoes in areas where plates meet.
Additionally, a volcano can be dormant when it has been inactive for a long time, or active when it erupts frequently.
A volcano erupts when the increasing pressure from the mantle on the Earth’s crust causes magma to rise through the volcano’s chimney to the surface. The opening where magma exits is called the crater, and the volcano can also expel solid materials like ash and gases.
Volcanoes modify the landscape because when lava cools, it creates new formations, expands continents, or even forms new islands.
In the following videos, you can see different images of real volcanoes:
- Volcanic eruption in Mexico
- Lava river in Hawaii
- Exploring the crater of Popocatépetl
Create your own visual diagram in your notebook with the information we have just covered. Here is an example:
Diagram on Volcanoes
Earthquakes
Earthquakes are sudden tremors in the Earth’s crust caused by the collision of two tectonic plates, fault movements, or volcanic eruptions. Their magnitude is measured with a SEISMOGRAPH and quantified using the RICHTER SCALE.
The area on Earth with the most earthquakes is the Ring of Fire, located along the edges of the Pacific Ocean.
The point where the earthquake originates is called the HYPOCENTER, which is located inside the Earth. The point on the surface where the earthquake is most destructive is called the EPICENTER, and tremors spread from the epicenter through SEISMIC WAVES. The farther a place is from the epicenter, the weaker the tremors will be.
When an earthquake or volcanic eruption occurs under the sea, it generates a SEISMIC SEA WAVE or TSUNAMI, which creates enormous waves. These waves grow larger as they approach the coast, causing massive destruction.
Watch these videos to understand it better:
- Exact moments of the 7.1 earthquake in Mexico
- Japan tsunami
Create your visual diagram on earthquakes in your notebook. You can copy it or make your own version.
Earthquake Diagram
Volcanoes and Earthquakes – Group Activity
We will divide the class into four groups. Two groups will research volcanoes, and the other two will research earthquakes. Using the information gathered and your textbook, you will create a poster representing key aspects of earthquakes and volcanoes. Finally, we will present the results to the rest of the class and evaluate the quality of each project, selecting a winner.
And here is the result of the activity…
EARTHQUAKES_VOLCANOES-01
And the winner that you have chosen is…
Earthquake poster
Self-Assessment
- What is a volcano? And how do they form?
- Observe the image and explain how a volcanic eruption occurs.
Source: ITE / Illustrator: José Alberto Bermúdez - Where do most volcanic eruptions occur?
- What do we mean when we say a volcano is dormant?
- Explain one of the main effects of a volcano.
- What is an earthquake? And how do they occur?
- Observe the image and explain earthquakes.
Source: ITE / Illustrator: José Alberto Bermúdez - What phenomenon generates a seismic wave?
- What does it mean when we say earthquakes occur as shakes?
- What is the Richter Scale?
- What is a tsunami?
