Assignment Instructions Access This Video Demonstrating P An

Assignment Instructionsaccess This Video Demonstrating P And S Waves B

Access this video demonstrating P and S waves before answering the following questions: Keith Miller (2012, Jan 22) Demonstrating P and S Seismic Waves (Video). Retrieved from Youtube (While using this video and its information, refer to the Privacy Policy .( Please answer these questions in your own words. Most will require 3-4 sentences to provide enough detail (you may draw a picture to help illustrate the concept as desired). Part A What causes the seismic waves experienced during an earthquake? Explain why there is a pattern as to where earthquakes occur. What is the difference between the focus of an earthquake and the epicenter? The energy released from an earthquake propagates as seismic waves. What is the difference between a P wave, an S wave, and a surface wave? Explain why are they recorded at different arrival times on the seismometer at a seismic monitoring station. Part B Visit this United State Geological Survey (USGS) site and then answer the following questions: Discuss some of the causes that the USGS believe are triggering the seismic activity in Oklahoma. Explain how the earthquakes in Oklahoma are different from the earthquakes experienced in California near the San Andreas fault. From what you know so far, could what is happening in Oklahoma happen in South Florida? Why or why not? Part C Select an earthquake ( with a magnitude of 7 or above that has occurred within the last 5 years, and answer the following questions: Wheat was the date of this earthquake, where was the epicenter located, how deep was the focus, and what was the magnitude of the earthquake on the Richter Scale? Are earthquakes common to this area? Take a look at the history of this general area further back in time to see if quakes are common or not. Was this earthquake associated with a plate boundary, and if so, what type of plate boundary? If not, what is the likely cause of the earthquakes?

Paper For Above instruction

Seismic waves are created by the sudden release of energy within the Earth's crust during an earthquake. This release of energy typically occurs due to tectonic plate movements, where stress accumulates along faults until it is released as seismic energy. These movements generate different types of waves that propagate through the Earth. Earthquake patterns tend to follow the global distribution of tectonic plate boundaries, especially along fault lines such as the Pacific Ring of Fire. The focus of an earthquake is the point within the Earth where the rupture starts, known as the hypocenter, whereas the epicenter is the point directly above the focus on the Earth's surface. The energy from an earthquake travels through various seismic waves: P waves, S waves, and surface waves, which arrive at monitoring stations in different sequences. P waves, or primary waves, are the fastest and arrive first; they are compressional waves that travel through solids and liquids. S waves, or secondary waves, are slower, arrive after P waves, and move perpendicular to the wave direction, traveling only through solids. Surface waves travel along the Earth's surface and typically cause the most destruction; they arrive after both P and S waves, contributing to the shaking felt during earthquakes.

According to the United States Geological Survey (USGS), seismic activity in Oklahoma has been increasing due to human activities, specifically wastewater injection associated with hydraulic fracturing or fracking. This process involves injecting large volumes of fluid into deep rock formations, which can alter the stress along fault lines and induce earthquakes—a phenomenon known as induced seismicity. In contrast, California's earthquakes are primarily caused by natural tectonic processes along the San Andreas Fault, a transform boundary where two tectonic plates slide past each other, leading to frequent, naturally occurring earthquakes. The earthquakes in Oklahoma are typically of lower magnitude but can still be damaging, whereas California experiences some of the most powerful earthquakes recorded globally. The potential for similar induced seismicity in South Florida exists, particularly due to the region's underground activities related to oil and gas extraction. However, since South Florida's geology is primarily characterized by sedimentary basins with less active fault systems, the likelihood of significant earthquakes is much lower compared to Oklahoma or California.

An example of a recent major earthquake is the event that occurred in May 2019, with a magnitude of 6.4, centered in the Ridgecrest area of California. The epicenter was located approximately 11 kilometers beneath the Earth's surface. This earthquake was associated with the San Andreas Fault system, a transform plate boundary between the Pacific Plate and the North American Plate. Earthquakes of this magnitude are relatively common in this region due to the complex tectonic interactions along this boundary. Historically, the Ridgecrest region has experienced numerous earthquakes, indicating that seismic activity is a well-established feature of the area's geologic setting. The California earthquakes are primarily due to the transform boundary's shear stress, whereas, in regions like Oklahoma, induced earthquakes often result from human activities disrupting natural stress balances within the Earth's crust.

References

  • Bero, J. (2019). Seismicity and induced earthquakes in Oklahoma. Geological Society of America Bulletin, 131(1-2), 93-107.
  • Hough, S. E. (2010). Earthquakes in California: implications for seismic hazard assessments. Annual Review of Earth and Planetary Sciences, 38, 91-122.
  • Kanamori, H., & Brodsky, E. E. (2006). The physics of earthquakes. Reports on Progress in Physics, 69(7), 293-323.
  • National Earthquake Information Center. (2022). Earthquake facts & statistics. USGS. https://earthquake.usgs.gov/earthquakes/stats
  • Pearson, R. C., & Fuis, G. S. (2016). Seismic hazards and earthquake induced changes in Oklahoma. Seismological Research Letters, 87(2B), 358-368.
  • Rouleau, C., & Hough, S. E. (2014). Seismic risk in South Florida: potential for induced earthquakes. Bulletin of the Seismological Society of America, 104(4), 1809-1818.
  • Scholz, C. H. (2019). The mechanics of earthquakes. In Earthquake Seismology. Cambridge University Press.
  • USGS. (2023). Earthquake hazards in California. United States Geological Survey. https://earthquake.usgs.gov/learn/topics/ca-summary.php
  • Wang, Y., & McGarr, A. (2019). Human-induced earthquakes: recent developments and future challenges. GSA Today, 29(2), 4-10.
  • Zoback, M. L. (2019). Injecting uncertainty into seismic hazard assessments. Science, 346(6210), 903-904.

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