Tectonics Topic 2 Quiz

During a geological survey, a team of scientists is studying the Earth's crust to understand seismic activity. They discover a specific point where seismic waves are released, which is identified as the origin of an earthquake. What is this point called?

• Epicentre

• Focus

• Fault

• Seismometer

Answer explanation

The point in the Earth's crust where seismic waves are released, marking the origin of an earthquake, is called the 'Focus'. The 'Epicentre' is the point directly above it on the surface.

During a recent earthquake, Anika was curious about the terminology used in seismology. She learned that the point on the Earth's surface directly above the focus of the earthquake is called what?

• Epicentre

• Focus

• Fault

• Seismometer

Answer explanation

The point on the Earth's surface directly above the focus of an earthquake is called the epicentre. It is where the seismic waves first reach the surface, making it crucial for understanding the earthquake's impact.

Fill in the blank: During a geology field trip, Ava learned that most earthquakes occur along ________, which are systems of deep fractures in the Earth's crust located at plate boundaries.

Answer explanation

Most earthquakes occur along faults, which are deep fractures in the Earth's crust found at plate boundaries. These faults are where tectonic plates interact, leading to seismic activity.

Fill in the blank: When stress exceeds the strength of the fault (or rock), the rocks snap or suddenly move to a new ________.

Answer explanation

When stress exceeds the strength of the fault, the rocks snap or suddenly move to a new position. This term accurately describes the change in location of the rocks after failure.

During a recent geology field trip, Priya and her classmates learned about earthquakes. Their instructor explained how scientists measure seismic waves to determine the magnitude of an earthquake by detecting ground vibrations. Which device did the instructor mention that is used for this purpose?

• Richter Scale

• Seismometer

• Moment Magnitude Scale

• Epicentre

Answer explanation

A seismometer is the device specifically designed to measure seismic waves and detect ground vibrations, allowing for the determination of an earthquake's magnitude. The Richter Scale and Moment Magnitude Scale are methods of quantifying this data.

During a recent earthquake in a small town, the local seismologist, Dr. Smith, used the Richter Scale (ML) to assess the magnitude of the quake. Based on which of the following factors did Dr. Smith calculate the earthquake's magnitude?

• Total energy released

• Height of the largest wave recorded on the seismometer

• Duration of the earthquake

• Number of aftershocks

Answer explanation

The Richter Scale measures earthquake magnitude by the height of the largest wave recorded on a seismometer, which reflects the energy released during the quake. Other options do not directly determine magnitude.

Fill in the blank: During a science fair, Mia presented her project on earthquakes. She explained that the Richter Scale is a ________ scale, where a magnitude 6.0 earthquake releases approximately 32 times more energy than a magnitude 5.0.

Answer explanation

The Richter Scale is a logarithmic scale, meaning each whole number increase on the scale represents a tenfold increase in measured amplitude and approximately 32 times more energy release, making 'logarithmic' the correct choice.

True or False: During a recent geology conference, experts discussed whether the Richter Scale is still commonly used by scientists for all types of earthquakes.

• True

• False

Answer explanation

False. The Richter Scale is largely outdated and has been replaced by the Moment Magnitude Scale (Mw) for measuring larger earthquakes, as it provides a more accurate assessment of seismic energy.

During a recent geological study, Aria learned that the Moment Magnitude Scale (Mw) rates earthquake magnitude based on the ________ released during the earthquake.

Answer explanation

The Moment Magnitude Scale (Mw) measures the total energy released during an earthquake, making 'total energy' the correct choice. This scale provides a more accurate representation of an earthquake's size compared to older scales.

Aiden is hiking in a mountainous region and comes across a large cone-shaped mountain that has smoke rising from its peak. Curious about this natural phenomenon, he wonders what it is.

• A landform created when magma erupts onto the Earth's surface, forming a cone-shaped mountain.

• A type of earthquake.

• A mountain formed by erosion.

• A river valley.

Answer explanation

A volcano is specifically defined as a landform created when magma erupts onto the Earth's surface, forming a cone-shaped mountain. This distinguishes it from earthquakes, erosion, and river valleys.