Earthquake Basics

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What are fault lines?

Fault lines are fracture lines along broken rocks that move.

What causes seismic activity?

Rocks pushing on each other, pulling apart from each other, or rubbing together cause seismic activity.

What are foreshocks?

Foreshocks are ground shaking events that occur before the main earthquake.

Why are aftershocks dangerous?

Aftershocks can be dangerous because they happen unpredictably days or weeks after the main earthquake, and structures may already be damaged and unable to handle more shaking. Signup and view all the answers

What is an aftershock?

An aftershock is a smaller earthquake that occurs after a larger earthquake. Signup and view all the answers

What causes aftershocks?

Aftershocks are caused by the transfer of energy when tectonic plates slip during an earthquake. Signup and view all the answers

What is a foreshock?

A foreshock is a smaller earthquake that occurs before a larger earthquake. Signup and view all the answers

Can foreshocks predict earthquakes?

No, foreshocks cannot predict earthquakes. It is impossible to know if a foreshock is a foreshock or a mainshock when it occurs. Signup and view all the answers

What is the definition of a foreshock?

A foreshock is a smaller earthquake that occurs prior to the mainshock in the same region. Signup and view all the answers

What is the definition of an aftershock?

An aftershock is a smaller earthquake that occurs following a mainshock in the same region. Signup and view all the answers

How are foreshocks and aftershocks different from mainshocks?

Foreshocks and aftershocks are smaller in magnitude than mainshocks. Signup and view all the answers

Can a foreshock be used to predict an earthquake?

No, it is not possible to predict an earthquake by measuring seismic activity from a foreshock. Signup and view all the answers

What are foreshocks and aftershocks?

Foreshocks are the energy release and ground shaking before an earthquake, while aftershocks are the energy release and ground shaking after an earthquake. Signup and view all the answers

Why are foreshocks less likely to do damage than aftershocks?

Foreshocks are smaller in magnitude compared to aftershocks. Signup and view all the answers

Can foreshocks be used to predict earthquakes?

No, foreshocks are usually too small and too close to the time of the main quake to help predict the main quake. Signup and view all the answers

Why can aftershocks continue to do damage to an area that has been hit by the main quake?

Aftershocks can continue to do damage because structures like buildings and roads are already rattled from the previous shaking event. Signup and view all the answers

What is the difference between a foreshock and an aftershock?

A foreshock is a smaller quake that occurs prior to the mainshock, while an aftershock is a smaller earthquake that occurs following a mainshock. Signup and view all the answers

How do geologists determine the strength of earthquakes?

Geologists use machines called seismographs to measure the strength of earthquakes. Signup and view all the answers

What is the mainshock of an earthquake?

The mainshock of an earthquake is the largest quake in a series, and occurs between a foreshock and aftershock. Signup and view all the answers

Why are aftershocks sometimes just as hazardous as the main quake?

Aftershocks may be so strong that they're stronger than the main quake, and they can continue to do damage to an area that has already been hit by the main quake. Signup and view all the answers