This PowerPoint presentation can be used in conjunction with the Earthquake Location activity. Use Slide Show mode to step through illustration of: (1) determining the arrival times of the P and S seismic waves at station GLA (Yuma, Arizona); (2) calculating the distance of the earthquake from station GLA; (3) determining the earthquake epicenter using the distance of the earthquake from station GLA and the other three seismic stations.
This PowerPoint presentation covers the basics of Cascade volcanoes and volcanic hazards. The presentation was developed by Beth Pratt-Sitaula and Jenda Johnson with assistance from Denise Thompson. Before veiwing this PowerPoint presentation, viewers are encouraged to review the PDF Introduction to Pacific Northwest Plate Tectonics, Earthquakes, and Volcanoes under the Cascadia Earthquakes and Tsunamis topic.
The basics of reading GPS time series plots are explained in this step wise, thorough, and nicely illustrated PowerPoint presentation developed by Shelley Olds at UNAVCO. This PowerPoint presentation can be used to support the Cascadia GPS Gumdrop Lesson Plan or simply for additional information for the teacher.
This PowerPoint presentation contains GPS time series plots for 10 Plate Boundary Observatory stations across the states of Washington and Oregon. These include four coastal stations (Neah Bay, Pacific Beach, Tillamook, and Newport); three stations in the urban corridor (Tumwater, Kelso, and Corvallis); and three stations located east of the Cascade Mountains (Othello, Wasco, and La Grande). Line fits to the north and east components of motion of these stations are shown and rates of north and east motion are provided for each station. Slide #1 is a map of the GPS station locations; Slide #32 is the same map with GPS velocity vectors plotted on the map; Slide #33 is a grid that can be used to plot the north and east components of motion and graphically add the components to determine the velocity vector in the horizontal plane.
This file is a zipped collection of PowerPoint Presentation along with associated QuickTime animations. The PowerPoint is 36 slides on the Japan magnitude 9.0 earthquake and resulting tsunami with comparisons to Cascadia past and future great earthquakes and tsunamis. You are welcome to download the zipped archive and use any or all elements for your own educational purposes. Please acknowledge Teachers on the Leading Edge as the source.
NOTE: If you download the PowerPoint and QuickTime files to a PC, you will likely need to reinsert the animations into the PowerPoint slides OR perhaps run the QuickTime animations in a MediaPlayer window rather than within PowerPoint.
This PDF provides a brief (12 page) introduction to regional plate tectonics, earthquakes, and volcanoes of the Pacific Northwest. The focus is mainly on the subduction zone (coast to Cascade Mountains) because that is where most of the earthquakes and volcanoes occur, and where tsunamis can be generated. This information was gathered and repurposed by Jenda Johnson and Bob Butler from the Pacific Northwest Seismograph Network (www.pnsn.org/), the U.S. Geological Survey (www.usgs.gov), and from two books: Orphan Tsunami of 1700, by Brian Awtater and others, and At Risk: Earthquakes and Tsunamis on the West Coast by John Clague and others.
Roger Groom, Mt Tabor Middle School, developed this activity while working with Becca Walker at UNAVCO in Boulder, Colorado. Through this activity, students can learn about an exciting discovery made possible by invention of high-precision GPS receivers and deployment of these receivers across the Pacific Northwest. This activity can be used to illustrate how invention of new technologies can lead to new scientific discoveries that would have been impossible without the new instruments; a good lesson in how science works.
Some background: The friction between a subducting and an overriding plate of a subduction zone changes with depth. At shallow depths from the surface to 20 km depth, friction is high and the subducting boundary remains locked between very large earthquakes that occur every few decades or centuries. Deeper than about 40 km, friction on the subduction zone is very low and the subducting plate slides into the mantle without major earthquakes on the interface between the two converging plates. In some subduction zones, there is a transitional behavior called “episodic tremor and slip” (ETS) that takes place at intermediate depths of 20 to 40 km. ETS events on the Cascadia subduction zone occur when the Juan de Fuca Plate slips a centimeter or two farther beneath the North American Plate over a time interval from a few days to about two weeks in duration. This “slow slip” is accompanied by release of seismic waves (tremor) that are much longer in duration than seismic waves released by standard earthquakes. Because this process increases the stress on the locked shallow portion of the subduction zone, the probability of a great subduction zone earthquake may be higher during ETS events than at other times so this discovery has important implications for earthquake risk.
This PowerPoint presentation covers basics of Cascadia earthquakes and tsunamis. Before veiwing this PowerPoint presentation, viewers are encouraged to view the PowerPoint presentations under the Introduction to Plate Tectonics and Earthquakes topic.
You are invited to download and modify this PowerPoint presentation for your own classroom teaching.
This PowerPoint presentation covers basics of tsunami hazards using the December 2004 Indian Ocean tsunami as an example. Before veiwing this PowerPoint presentation, viewers are encouraged to view the PowerPoint presentations on Plate Tectonics and Earthquake Seismology available under the Introduction to Plate Tectonics and Earthquakes topic.
This PowerPoint presentation covers basics of earthquake hazards, damage to structures due to earthquakes, and building designs that can make structures earthquake resistant.