1.
What is the Mohorovičić discontinuity (Moho) primarily associated with?
Correct Answer
A. Crust and Mantle boundary
Explanation
The Mohorovičić discontinuity, colloquially referred to as the Moho, represents a profound boundary between the Earth's crust and the underlying mantle. This seismic discontinuity is characterized by a significant change in seismic wave velocity, typically marking the transition from the relatively rigid and brittle crust to the more ductile and dense mantle beneath. The Moho's depth can vary greatly depending on factors such as tectonic activity, crustal thickness, and geological settings. It plays a crucial role in understanding the composition and structure of the Earth's lithosphere and asthenosphere, offering insights into processes like plate tectonics and crustal deformation.
2.
The Gutenberg Discontinuity is primarily associated with the boundary between which layers of the Earth?
Correct Answer
A. Mantle and Outer Core
Explanation
The Gutenberg Discontinuity is a pivotal boundary separating the Earth's mantle from the outer core. This transition is marked by a drastic reduction in seismic wave velocity, indicating the change from the solid, rocky mantle to the molten, metallic outer core. Situated approximately 2,900 kilometers beneath the Earth's surface, the Gutenberg Discontinuity is crucial for discerning the Earth's internal dynamics and heat transfer mechanisms. It plays a fundamental role in studies related to geomagnetism, geodynamics, and the generation of Earth's magnetic field through the dynamo effect.
3.
Which discontinuity marks the boundary between the Earth's outer core and mantle?
Correct Answer
C. Gutenberg Discontinuity
Explanation
The Gutenberg Discontinuity, known as the boundary between the Earth's mantle and outer core, represents a profound shift in seismic wave behavior, denoting the transition from solid to liquid. This seismic discontinuity, situated at approximately 2,900 kilometers beneath the Earth's surface, holds significant importance in understanding the Earth's internal structure and dynamics. It plays a crucial role in studies related to seismology, geodynamics, and the Earth's magnetic field generation mechanism.
4.
The Lehmann Discontinuity is associated with the boundary between which layers of the Earth?
Correct Answer
B. Mantle and Inner Core
Explanation
The Lehmann Discontinuity, named after Danish seismologist Inge Lehmann, signifies the boundary between the Earth's mantle and inner core. This seismic boundary is characterized by a sudden increase in seismic wave velocity, indicating the transition from the liquid outer core to the solid inner core. Situated approximately 5,150 kilometers beneath the Earth's surface, the Lehmann Discontinuity plays a pivotal role in understanding the Earth's deep interior dynamics, including the generation of the geomagnetic field and the nature of seismic waves propagating through the core.
5.
What is the depth range of the Mohorovičić Discontinuity (Moho)?
Correct Answer
B. 30-60 kilometers
Explanation
The Mohorovičić Discontinuity (Moho) typically resides at depths ranging from 30 to 60 kilometers beneath the Earth's surface, although its depth can vary depending on geological settings and crustal composition. This seismic boundary marks the interface between the Earth's brittle crust and the underlying ductile mantle. The Moho plays a critical role in geological studies, offering insights into crustal thickness variations, crustal composition, and the tectonic processes shaping the Earth's surface.
6.
Which discontinuity marks the boundary between the Earth's crust and mantle?
Correct Answer
A. Mohorovičić Discontinuity
Explanation
The Mohorovičić Discontinuity, commonly known as the Moho, delineates the boundary between the Earth's outermost layer, the crust, and the underlying mantle. This transition is characterized by a distinct change in seismic wave velocity, reflecting the differing physical properties of these geological layers. Understanding the Moho's depth and characteristics is essential for various geological investigations, including crustal structure analysis, earthquake studies, and exploration of natural resources.
7.
What is the approximate depth of the Gutenberg Discontinuity?
Correct Answer
A. 100 kilometers
Explanation
The Gutenberg Discontinuity is typically located at a depth of around 100 kilometers beneath the Earth's surface, although its depth may vary depending on geological factors and regional variations. This seismic boundary separates the Earth's mantle from the outer core and is characterized by a significant decrease in seismic wave velocity. Knowledge of the Gutenberg Discontinuity's depth and properties is crucial for understanding the Earth's internal dynamics, including mantle convection, heat transfer, and the generation of Earth's magnetic field.
8.
The Lehmann Discontinuity is named after who?
Correct Answer
A. Inge Lehmann
Explanation
The Lehmann Discontinuity, named after the Danish seismologist Inge Lehmann, is a seismic boundary marking the transition between the Earth's mantle and inner core. Situated at approximately 5,150 kilometers beneath the Earth's surface, this discontinuity is characterized by a sudden increase in seismic wave velocity, indicating the change from the liquid outer core to the solid inner core. Inge Lehmann's discovery of this boundary revolutionized our understanding of the Earth's deep interior and paved the way for further exploration of its dynamics.
9.
What type of seismic waves do not pass through the Earth's liquid outer core but do pass through the solid inner core?
Correct Answer
B. S-waves
Explanation
S-waves, or secondary waves, are a type of seismic wave that propagates through solid materials. However, they cannot pass through the Earth's liquid outer core due to its fluid nature. S-waves exhibit a shearing motion perpendicular to their direction of travel, making them unable to transmit through fluids. Nevertheless, S-waves can traverse through the solid inner core, although they experience refraction and reduced velocity due to the differences in material properties.
10.
Which discontinuity marks the boundary between the Earth's inner core and outer core?
Correct Answer
D. Conrad Discontinuity
Explanation
The Conrad Discontinuity, situated at the boundary between the Earth's inner core and outer core, represents a significant transition in seismic wave behavior. This boundary is characterized by a change in seismic wave velocity, indicating the shift from the solid inner core to the liquid outer core. The Conrad Discontinuity plays a crucial role in understanding the Earth's internal structure and dynamics, including the generation of Earth's magnetic field and the behavior of seismic waves as they travel through the core-mantle boundary.