76 Questions
Which seismic waves are the most damaging of all the seismic waves?
Rayleigh waves
What is the fastest type of seismic wave?
P-waves
What is the seismic wave type that moves across the surface like a wave in the ocean?
Rayleigh waves
Which scale is most useful for measuring mid-range earthquakes?
Richter Scale
What type of seismic wave is more damaging than P-waves?
S-waves
How do geologists measure the strength of earthquakes?
Seismographs
What is the main cause of fires during earthquakes?
All of the above
What is the main difference between magma and lava?
Magma is under the crust, while lava is above the crust
Which type of volcano is the most explosive?
Composite cone
What is the main effect of sulfur dioxide aerosols from volcanic eruptions?
They reflect the sun's rays into space
What is the main component of lava?
All of the above
What is the relationship between the amount of silica in lava and its viscosity?
The more silica, the higher the viscosity
What are the three types of morphologies associated with mafic lava flows?
Pahoehoe, Aa, and pillow
What differentiates nuee ardente flow from pumice flow deposits?
Nuee ardente has block-and-ash flow while pumice is a pyroclastic surge
What is the primary distinguishing feature of intermediate lava?
Blocky morphologies
How are pyroclastic surges different from pyroclastic flows?
Surges have higher gas content and lower rock fragments than flows
How do volcanic plateaus form?
From thick, easily flowing lava spreading over a wide area
What process is responsible for the formation of the Mid-Ocean Ridge?
Sea floor spreading
What is the pattern observed in the magnetic polarity of the oceanic crust near the Mid-Ocean Ridge?
The polarity alternates between normal and reversed as you move away from the ridge
What conclusion did scientists draw from the alternating pattern of magnetic polarity in the oceanic crust?
The Earth's magnetic field has flip-flopped over the years
Which of the following statements about earthquakes is true?
Earthquakes can occur both on land and underwater
Which of the following is NOT a type of fault mentioned in the text?
Thrust fault
What can underwater earthquakes potentially trigger?
Tsunamis
What percentage of the world's volcanoes are located along the Ring of Fire?
75%
Which of the following is NOT considered a volcanic hazard?
Tephra
What is the key difference between pyroclastic flows and pyroclastic surges?
Both a and b are correct.
What is a lahar?
A landslide of volcanic debris and water
Which of the following is the LEAST deadly volcanic hazard?
Lava flows
What can cause a volcanic earthquake?
Both a and b are correct
What is the best preventative measure for protecting against lahars?
Evacuating people and developing a warning system
How can a tsunami be triggered by volcanic activity?
By the volcanic earthquake shaking the ocean floor
What is the main difference between a foreshock and a mainshock?
A foreshock is a smaller quake that occurs before the mainshock, while the mainshock is the largest quake in the series.
What is the main difference between the Richter scale and the moment magnitude scale?
The Richter scale uses the value of the amplitude of the highest seismic wave, while the moment magnitude scale uses the seismic moment to measure intensity.
How does the energy released by earthquakes increase as the magnitude on the Richter scale increases?
The energy released increases by a factor of 1,048,576 from a magnitude 4 to a magnitude 8 earthquake.
What is one of the main effects that an earthquake can have on the landscape?
Earthquakes can cause the ground to liquefy, where wet soil and sediment move and act like a liquid.
What is one of the main effects that an earthquake can have on human-made structures?
Earthquakes can cause power and gas lines to rupture, leading to widespread power outages and fires.
What is the main process responsible for the formation of the Mid-Ocean Ridge?
Sea floor spreading
What pattern is observed in the magnetic polarity of the oceanic crust near the Mid-Ocean Ridge?
The polarity alternates between normal and reversed
What is the main conclusion that scientists drew from the alternating pattern of magnetic polarity in the oceanic crust?
The Earth's magnetic field has reversed direction multiple times
What is the main effect that an underwater earthquake can have?
Cause a tsunami
What are the three main types of faults mentioned in the text?
Reverse, normal, and strike-slip
What is the main cause of earthquakes according to the text?
Plate tectonics
What is the most common gas emitted during a volcanic eruption?
Water vapor
How does the viscosity of lava relate to its silica content?
Higher silica content leads to higher viscosity
What is one of the main negative effects of sulfur dioxide released during volcanic eruptions?
It causes acid rain
What is the main difference between magma and lava?
Magma is underground, while lava is on the surface
Which of the following is NOT a type of volcanic eruption mentioned in the text?
Phreatic
What is the primary effect of carbon dioxide released during volcanic eruptions?
It is a greenhouse gas that traps heat
What is the source of seismic waves during an earthquake?
The release of stress or pressure at the fault rupture
What type of seismic waves travel through the interior of the Earth?
P-waves and S-waves
What is the term used to describe the location on Earth's surface directly above the focus of an earthquake?
Epicenter
Which of the following regions is NOT mentioned as one of the three major areas where most earthquakes occur?
The Mid-Atlantic Ridge
What is the term used to describe the mechanism or device used to measure seismic activity during an earthquake?
All of the above
What is the primary cause of most earthquakes, according to the text?
The slipping of tectonic plates
What is the difference between a foreshock and an aftershock?
A foreshock is a smaller quake that occurs before the mainshock, while an aftershock is a smaller quake that occurs after the mainshock.
What is the relationship between the magnitude of an earthquake and the amount of ground shaking?
As the magnitude increases, the amount of ground shaking increases exponentially.
Which scale is better suited for measuring the magnitude of large earthquakes?
The moment magnitude scale
What is the primary function of a seismograph?
To detect seismic activity and measure the amplitude of seismic waves
What is the main cause of structural damage during an earthquake?
Ground shaking
Which of the following is NOT a potential effect of an earthquake?
Volcanic eruptions
What is the primary factor that determines the viscosity of lava?
Silica content of the lava
Which of the following is NOT a characteristic of pyroclastic flows?
They move very slowly
What is the primary difference between a nuee ardente flow and a pumice flow?
Nuee ardente flows have a higher density of lava fragments
What is the primary distinguishing feature of felsic lava?
It explodes from lava domes
What is the primary mechanism responsible for the formation of a volcanic pipe?
Pressure buildup in a magma chamber
What is the primary difference between a crater and a caldera?
A caldera is a large crater formed by the emptying of a magma chamber
Which region is known for having a high concentration of volcanoes?
The Ring of Fire
Which of the following is NOT considered a volcanic hazard?
Earthquakes
What is the main difference between pyroclastic flows and pyroclastic surges?
Pyroclastic surges contain more gas than pyroclastic flows
What is a lahar?
A flowing mass of volcanic debris and water
How can a tsunami be triggered by volcanic activity?
By a landslide
What is the main reason that lava flows are considered less deadly than other volcanic hazards?
They move at slower speeds
What is the primary reason that pyroclastic surges are considered deadly?
The presence of highly heated toxic gases
What is the main concern associated with tephra?
It can negatively impact respiratory health
What percentage of the world's volcanoes are located along the Ring of Fire?
75%
What is the best preventative measure for protecting against lahars?
Evacuating people and developing a warning system
Test your knowledge on the formation of the Mid-Ocean Ridge and sea floor spreading, where new oceanic crust is created through the upwelling of magma. Learn about the alignment of magnetic fields in younger stripes of ocean floor and the movement of older rocks away from the ridge crest.
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