Evelyn Ngo GEOL 1121L – Section 034 11 November 2022 The Significance of the Pacific Ring of Fire A large horse-shoe pattern of volcanoes resides where coasts of land meet the Pacific Ocean. The 40,000-kilometer ring spans across four continents: North America, South America, Australia, and Asia, and is trailed by numerous island chains. This pattern is not by coincidence. Volcanoes, ocean trenches, and earthquakes are the byproduct of processes between interacting plate boundaries; the Pacific Ring of Fire consists of all these phenomena. It traces the boundaries of an oceanic tectonic plate called the Pacific Plate, the largest among the seven major tectonic plates, and holds the most catastrophic natural disasters in history as a result of volcanic and earthquake activity. Plate tectonic theory was discovered by geophysicist Alfred Wegener in 1915 with his proposal of “continental drift” theory, the idea that the Earth was broken up from one continent into separate masses that slowly move away from each other, but it was not until the 1960s when his theory began to be fully realized. Seismometers designed after WWII revealed a pattern of earthquakes and volcanoes present along the boundaries of tectonic plates. Active geological activities are the result of different types of plate tectonic boundaries that are defined by the interactions between two plates. Tectonic plates are constantly moving away, towards, or against each other and are categorized as divergent, convergent, or transform plates based on these movements. The Pacific Plate consists of all three boundary types. One notable example of a transform plate boundary along the Pacific Plate and the North American Plate is the San Andreas Fault, where if enough stress is built along the fault from colliding rock, the resulting breakage will send vibrations known as earthquakes. The San Andreas Fault produces thousands of earthquakes per year in California, some historically disastrous enough to collapse buildings and claim hundreds of casualties. Similar seismic activity is reflected in other places along the Pacific Plate like Japan and New Zealand. According to the U.S. Geological Survey, the Pacific Ring of Fire hosts about 81 percent of Earth’s largest earthquakes, like the M9.5 Chilean Earthquake, caused by the subduction of oceanic crust. Volcanoes are also formed through divergent and convergent boundaries in addition to hot spots along the Pacific Ring of Fire. The collision of convergent plate boundaries at subduction zones can cause magma to rise to the surface and form volcanic arcs. The state of Alaska hosts the Aleutian Islands and its 40 active volcanoes that trail the boundary between the Pacific and North American tectonic plates. The subduction of these two plates created the deep Aleutian Trench and a cluster of large volcanic islands. Another source of volcanic activity on the Pacific Plate is the hot spot forming the Hawaiian Islands. In the middle of the Pacific Plate, magma melts through the crust and consolidates on the surface to form volcanic islands as the plate slowly moves over the hot spot. Most of Earth’s Evelyn Ngo GEOL 1121L – Section 034 11 November 2022 subduction zones and magma plumes are found along the Pacific Ring of Fire, thus contextualizing the abundance of volcanic arcs caused by movement of the Pacific Plate. The significance of understanding the Pacific Ring of Fire and its processes will help us conceive of necessary precautions in the event of major seismic and volcanic activity. Our knowledge of plate tectonics may not help us fully predict when these disasters will occur, but the work of scientists analyzing the rate of plate movement, changes in Earth’s magnetic field, volcanic gas emissions, and seismic waves will help us prepare our infrastructure in the event of such catastrophe. Evelyn Ngo GEOL 1121L – Section 034 11 November 2022 References Glasscoe, Maggi. “History of Plate Tectonics.” The Southern California GPS Network Education Module, The Southern California GPS Network, 13 Aug. 1998, http://scecinfo.usc.edu/education/k12/learn/plate2.htm. “How Do Scientists Forecast Eruptions?” Edited by E Venske, Global Volcanism Program, Smithsonian Institution, 2022, https://volcano.si.edu/faq/index.cfm?question=eruptionforecast#:~:text=Scientists%20use%20a %20wide%20variety,and%20changes%20in%20gravity%20and. “How Volcanoes Form.” British Geological Survey, British Geological Survey, 23 June 2021, https://www.bgs.ac.uk/discovering-geology/earth-hazards/volcanoes/how-volcanoes-form “Pacific Plate: Movement and Direction of the Pacific Tectonic Boundary.” Earth How, EarthHow, 12 May 2022, https://earthhow.com/pacific-plate/. “Plate Tectonics and the Ring of Fire.” Edited by Jeannie Evers, National Geographic, National Geographic Society, 15 July 2022, https://education.nationalgeographic.org/resource/platetectonics-ring-fire. Schulz, Sandra S., and Robert E. Wallace. “The San Andreas Fault.” USGS, U.S. Geological Survey, 30 Nov. 2016, https://pubs.usgs.gov/gip/earthq3/safaultgip.html. Weisberger, Mindy. “Chain of Alaskan Islands Might Really Be One Monster Volcano.” LiveScience, Live Science, 7 Dec. 2020, https://www.livescience.com/small-islands-one-big-volcano.html. “Where Do Earthquakes Occur?” U.S. Geological Survey, U.S. Geological Survey, https://www.usgs.gov/faqs/where-do-earthquakes-occur. Yeats, Robert S. Plate Tectonics. Oregon State University, 20 Aug. 2018, https://open.oregonstate.education/earthquakes/chapter/plate-tectonics/.
