Earthquakes Lecture Review

These flashcards cover key concepts related to earthquakes, including their causes, effects, and significant historical events.

What are aftershocks?

Aftershocks are shocks that people feel for hours or even days after an earthquake.

What is a fault?

A fault is a crack in the Earth’s surface where rocks break and slip.

What is the Earth's outermost layer called?

The crust.

What are tectonic plates?

Tectonic plates are huge rocks broken into large sections that make up the Earth's crust.

How fast do tectonic plates move?

Tectonic plates move slowly at a rate of 2-12 cm per year.

What can happen when two tectonic plates meet?

They can separate, collide, or slide past one another.

What is the focus or hypocentre of an earthquake?

The focus is the place underground where the energy is released during an earthquake.

What is the epicentre of an earthquake?

The epicentre is the point on the Earth's surface directly above the focus of the earthquake.

What determines the ground motions caused by seismic waves?

The depth of the focus, the type of rock found locally, and the magnitude of the earthquake.

What is the Moment Magnitude Scale?

It is the scale used to measure the magnitude of an earthquake based on the energy released.

Where was the largest earthquake ever recorded?

The largest earthquake recorded was in southern Chile in May 1960 with a magnitude of 9.5.

Why are eastern Canada earthquakes felt farther away than western ones?

Due to differences in geology between the areas.

What causes earthquakes in Eastern Canada?

Stresses within the plate, and postglacial rebound can cause earthquakes.

What is postglacial rebound?

It is the process where land rises after being depressed by a glacier.

What is the Pacific Ring of Fire?

A region where approximately 90% of the world's earthquakes and 75% of the world's volcanoes occur.

What was the magnitude of the earthquake that hit Haiti on January 12, 2010?

The magnitude was 7.0.

What earthquake caused severe damage in Saguenay, QC?

The 1988 earthquake with a magnitude of 5.8 caused over $25 million in damage.

What should you develop to prepare for an earthquake?

An emergency plan and an emergency kit to survive for 72 hours.

What is the range of depths for earthquake foci in Canada?

Foci can range from 1 to 100 km deep.

How are earthquakes monitored in Canada?

Using approximately 220 seismograph stations operated by the Geological Survey of Canada.

What type of earthquakes are caused by human activity?

Earthquakes triggered by activities such as mining, dam reservoirs, and nuclear explosions.

What significant earthquake occurred off Vancouver Island in 1700?

It had an estimated magnitude of 9.

What is meant by seismic waves?

Seismic waves are energy waves that radiate out in all directions during an earthquake.

What is the historical significance of the earthquake in Haida Gwaii in 1949?

It was the largest earthquake ever recorded in Canada at a magnitude of 8.1.

Which region in Canada is the most earthquake-prone?

The Pacific Coast.

How often does an earthquake occur in the Western Quebec Seismic Zone?

On average, an earthquake occurs every 5 days.