Natural Hazards: Module Review

Long streams of molten rock from volcanoes are called _____.

• volcanic ash

• a caldera

• lava flows

• a seismic event

Answer explanation

Long streams of molten rock that flow from a volcano are known as lava flows. This term specifically describes the movement of lava, distinguishing it from volcanic ash, which consists of fine particles, and other terms.

Tags

NGSS.MS-ESS2-1

NGSS.MS-ESS2-2

Volcanoes can form on the ocean floor.

• False

• True

Answer explanation

True. Volcanoes can indeed form on the ocean floor, primarily at tectonic plate boundaries or hotspots, where magma rises to the surface, creating underwater volcanic structures.

Tags

NGSS.MS-ESS2-3

Breaks in Earth's lithosphere (crust) are called fractures.

• False

• True

Answer explanation

The statement is false because breaks in Earth's lithosphere are specifically called faults, while fractures refer to any break in the rock, not necessarily involving movement.

Most earthquakes occur in the centers of continents.

• False

• True

Answer explanation

Most earthquakes occur along tectonic plate boundaries, not in the centers of continents. Therefore, the statement is false.

Tags

NGSS.MS-ESS3-2

For the moment magnitude scale, each increase on the scale represents 31.5 times more energy released by the earthquake. Which is a good estimate of about how much more motion there is for a magnitude 7 earthquake than a magnitude 4 earthquake?

• 90 times

• 27,000 times

• 900 times

• 3000 times

Answer explanation

A magnitude 7 earthquake is 3 magnitudes higher than a magnitude 4. Each increase represents 31.5 times more energy, so 31.5^3 = 31.5 * 31.5 * 31.5 ≈ 27,000 times more motion, making 27,000 the correct estimate.

Tags

NGSS.MS-ESS3-2

“We all got scared and ran outside. The house was ok, but our old shed fell over.” This quote would help a researcher to place an earthquake on which scale?

• Richter Scale

• Modified Mercalli Scale

• moment magnitude scale

• all answers are correct

Answer explanation

The quote describes the effects of an earthquake, focusing on human reactions and structural damage. This aligns with the Modified Mercalli Scale, which measures the intensity of shaking based on observed effects, unlike the Richter or moment magnitude scales.

Tags

NGSS.MS-ESS3-2

Earthquakes are associated with _______________.

• hurricanes

• faults

• droughts

• pyroclastic flows

Answer explanation

Earthquakes occur due to the movement of tectonic plates along faults. These faults are fractures in the Earth's crust where stress builds up and is released as seismic energy, causing earthquakes.

Tags

NGSS.MS-ESS3-2

The magnitude of an earthquake is measured by the __________________.

• Richter scale

• Seismic Scale

• Modified Mercalli Scale

• EF Scale

Answer explanation

The magnitude of an earthquake is measured by the Richter scale, which quantifies the energy released during an earthquake. Other scales, like the Modified Mercalli Scale, measure intensity but not magnitude.

Fill in the blank The Richter scale is based on the height of the lines traced by a(n) ____________.

• seismograph

• seismotography

• seismic radiation

• epicenter

Answer explanation

The Richter scale measures the magnitude of earthquakes based on the height of the lines traced by a seismograph, which records seismic waves. Therefore, 'seismograph' is the correct choice.

Which of the following is NOT studied by geologists to predict volcanic eruptions?

• ground deformation

• earthquake swarms

• animal behavior

• change in shape of the volcano

Answer explanation

Animal behavior is not a scientific method used by geologists to predict volcanic eruptions. Instead, they study ground deformation, earthquake swarms, and changes in the shape of the volcano.

Tags

NGSS.MS-ESS3-2