Volcanoes and earthquakes notes

What is a volcano?

A volcano is an opening in the Earth where molten rock, ash, and gases escape.

How do volcanoes form?

Volcanoes form when magma from inside the Earth pushes through cracks in the surface.

True or false: All volcanoes erupt.

False, because some volcanoes are dormant and may not erupt for thousands of years.

What causes an earthquake?

Earthquakes are caused by the sudden release of energy in the Earth's crust, usually due to tectonic plate movements.

Difference between magma and lava.

Magma is molten rock beneath the Earth's surface; lava is magma that has reached the surface.

Fill in the blank: The point on the Earth's surface directly above an earthquake's origin is called the _____ .

epicenter.

What is a tectonic plate?

Tectonic plates are large sections of the Earth's crust that move and interact with each other.

What is the Ring of Fire?

The Ring of Fire is a horseshoe-shaped area in the Pacific Ocean known for its high volcanic and seismic activity.

True or false: Earthquakes can only occur near volcanoes.

False, because earthquakes can happen anywhere on Earth, not just near volcanoes.

How do scientists measure earthquakes?

Scientists use a seismometer to detect and record the vibrations caused by earthquakes.

What is an aftershock?

An aftershock is a smaller earthquake that occurs after a larger one in the same area.

Fill in the blank: The scale used to measure earthquake magnitude is called the _____ scale.

Richter.

Difference between a shield volcano and a composite volcano.

A shield volcano has gentle slopes and erupts fluid lava; a composite volcano has steep slopes and erupts more explosive material.

What is a lava flow?

A lava flow is the movement of lava as it erupts and flows down the sides of a volcano.

Fill in the blank: A volcano that has not erupted in a long time is called _____ .

dormant.

What is pyroclastic flow?

Pyroclastic flow is a fast-moving current of hot gas and volcanic matter that flows down from a volcano.

True or false: All earthquakes are strong and destructive.

False, because many earthquakes are too small to be felt.

What is the focus of an earthquake?

The focus is the point inside the Earth where the earthquake originates.

How does a volcanic eruption affect the environment?

Eruptions can cause ash fall, lava flows, and gases that can harm plants, animals, and air quality.