module 2 extra credit

.docx

School

Ivy Tech Community College, Indianapolis *

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Course

100

Subject

Geology

Date

Dec 6, 2023

Type

docx

Pages

2

Uploaded by GrandTitanium11150

Question 1 2.5 / 0 pts In your own words, compare and contrast the types of seismic waves. Please be specific & detailed in your answer. Your Answer: Seismic waves are covered on page 133 of our textbook. They are the energy waves generated by earthquakes or other geological events, and they play a crucial role in understanding the Earth's interior and the effects of such events. There are three main types of seismic waves: P-waves (primary waves), S-waves (secondary waves), and surface waves. P-waves and S-waves are both types of body waves. 1. P-Waves (Primary Waves): These are the fastest seismic waves and are the first to arrive at a seismograph station after an earthquake. They travel through solid, liquid, and gaseous materials. These waves travel about 70% faster than S-waves. These waves have a back-and-forth motion and can pass through the Earth's mantle and core. P-waves are responsible for causing the initial, abrupt shaking felt during an earthquake. 2. S-Waves (Secondary Waves): These waves are slower than P-waves and arrive at seismograph stations after P-waves. They are shear waves that can only travel through solid materials. These weaves move side to side or in a transverse motion causing materials to vibrate perpendicular to their direction of travel. S-waves cannot pass through liquids, so they are unable to travel through the Earth's outer core since it is molten. S-waves are responsible for the more significant shaking and ground displacement than the P-waves, however they are not as damaging as the surface waves. 3. Surface Waves: Surface waves are the slowest of all seismic waves, and as the name suggests, they travel along the Earth's surface. There are two types of surface waves. One causes things to move in a side-to-side motion similar to S-waves but are contained to the Earth's surface. The other causes things to move both vertically and horizontally. Surface waves do not penetrate deep into the Earth's interior, but they are responsible for the most destructive shaking during an earthquake and are the primary cause of structural damage due to the large amplitudes. Question 2 3 / 0 pts In your own words, define the Theory of Plate Tectonics. How does ocean drilling help to prove the Theory of Plate Tectonics. Please be specific & detailed in your answer. Your Answer: This subject is covered in our textbooks from page 99-111.
The Theory of Plate Tectonics is a fundamental concept in geology that explains the movement and interactions of the Earth's lithospheric plates, which make up the Earth's outer shell. The theory proposes that the Earth's lithosphere is divided into several rigid plates that float on the semi-fluid asthenosphere beneath them. These plates are in constant motion, and their interactions at plate boundaries are responsible for a wide range of geological phenomena, including earthquakes, volcanic eruptions, the formation of mountain ranges, and the shaping of continents. Plates interact with each other at their boundaries. There are three primary types of plate boundaries. Divergent plate boundaries where plates move away from each other creating new oceanic crust, mid-ocean ridges, and rift valleys. Convergent plate boundaries where plates move towards each other, resulting in subduction zones, where one plate sinks beneath the other, leading to the formation of deep-sea trenches, volcanic arcs, and mountain ranges. Transform plate boundaries where plates slide past each other horizontally, causing strike-slip faults and lateral motion along the boundary. The driving force behind plate motion is because of the convection currents in the asthenosphere. Heat generated from the Earth's interior causes material to rise at mid- ocean ridges, cool, and then sink back into the mantle at the subduction zone. This convective motion propels the plates movement. Ocean drilling has played a significant role in proving the Theory of Plate Tectonics. 1. Mid-Ocean Ridges: Ocean drilling has allowed scientists to study the ocean floor and confirm the existence of mid-ocean ridges, which are underwater mountain ranges where new oceanic crust is formed through volcanic activity. This discovery provided critical evidence for the concept of divergent plate boundaries. 2. Subduction Zones: By drilling into the seafloor at subduction zones, researchers have collected samples of the Earth's crust and upper mantle that provide insights into the processes occurring at convergent plate boundaries. These samples have confirmed the subduction of oceanic plates beneath continental or other oceanic plates. 3. Seafloor Spreading: The analysis of seafloor sediment cores and the age of oceanic crust samples obtained through drilling have supported the idea of seafloor spreading, a key component of plate tectonics. The farther one moves from a mid-ocean ridge, the older the oceanic crust becomes, which aligns with the prediction of the theory. 4. Volcanic Activity: Drilling in oceanic regions has allowed scientists to investigate the composition of volcanic rocks and the presence of hotspots. These findings help explain the formation of volcanic island chains and support the notion that these features are related to the movement of tectonic plates over mantle plumes.
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