GEOG 310 Lab 2 Plate Boundaries and Hazards.docx

GEOG 310 W24 S. Jones Lab 2: Plate Boundaries and Natural Hazards Now that you have had a chance to explore plate tectonics and some associated landforms, let’s consider some of the natural hazards associated with different boundary types. Start by launching National Geographic MapMaker in an internet browser. MapMaker is a tool created by the National Geographic Society and Esri with a CC BY-NC-SA 4.0 International license. - Site address: https://help-mpmkr.hub.arcgis.com/ - Navigate to the site and click “Launch the app.” - Once MapMaker has launched, click the “Open map” option on the menu bar at the bottom and select the map called “Plate Tectonics.” - Orient yourself by practicing zooming and panning. - Click on “Map layers” to view information about the layers currently displayed on the map. You can toggle layers on and off with the eye button next to the title of each layer in the legend. Part 1: Transform boundaries Set up your map: - The plate tectonics map opens with the “Earthquakes (Major)” layer on. Toggle this layer off in the “Map layers” window. - Click “Add layer” in the menu bar, the navigate to the Physical Science ± Natural Hazards category using the list on the right side of the “Add layer” window. - Use the + sign to add “Earthquakes (Last 30 Days)” to your map. Click the x to exit the “Add layer” window and open the “Map layers” window again to view information about the “Earthquakes (Last 30 Days)” layer. - Toggle on the “Plate Boundaries” layer. Question 1.1 : Pan around the map. What do you notice about the distribution of earthquakes? In the western hemisphere (North and South America) The earthquake distribution is pretty light compared to the eastern hemisphere. All the earthquakes appear along the west coasts of both the continents. Compared the the eastern hemisphere all the earthquakes seem to happen around the east and south coasts. Due to the plate boundaries being mostly around these areas Question 1.2 : Zoom into California, USA. The San Andreas fault is a transform plate boundary that runs through California. Recall that plates at transform boundaries are sliding past each other. The Pacific Plate is moving to the NW and sliding along the edge of the North American Plate. The North American Plate is moving to the SW in general, but at this location is moving SE relative to the Pacific Plate. Look at the information in the “Map Layers” window. What do you notice about the magnitude of most of the recent earthquakes in this area displayed on your map? The magnitude of the earthquakes in the California area is quite low on the Richter scale with the strongest being at level 5 magnitude in the past thirty days. Page 1 of 4

GEOG 310 W24 S. Jones Question 1.3 : Toggle on the “Major Earthquakes” layer. Click on any three of the earthquakes close to the San Andreas fault and note the date the earthquake occurred, the magnitude, and the depth. Date Magnitude Depth July 21, 1952 7.5 6 June 28, 1992 7.3 -0 January 18, 2024 1 7 Although most of the earthquakes in this region are relatively small as you noted in the previous question, there are occasional big ones! Question 1.4 : Toggle on the “Volcanic Eruptions (Significant)” layer and zoom out. What do you notice when you compare the locations of volcanic eruptions and the location of the transform plate boundary at the San Andreas fault? The first major observation is that there are no Volcanoes present along the San Andreas fault line. The reason being scenes there's no subduction or ripping occurring along the fault there for no magma can be formed and create volcanoes Part 2: Convergent boundaries Leave the “Volcanic Eruptions (Significant)” and “Major Earthquakes” layers toggled on. Explore the map and select an area that has both large eruptions and large earthquakes. (Do not select Iceland or Hawaii for this part of the lab as they are also influenced by hot spots.) Question 2.1 : Record the location that you chose to focus on. Indonesia Question 2.2 : Click on any three eruptions and any three earthquakes and note the dates, and other info in the tables below. A sample row is completed in each table to get you started. Earthquakes: Date (Year) Magnitude Depth 1996 8.1 33 km January 1, 1996 7.9 24 January 23,1965 8.2 20 March 28,2005 8.6 30 Volcanic eruptions: Date (Year) Name Type * VEI ** Page 2 of 4

GEOG 310 W24 S. Jones Toggle off the “Tectonic Plates” layer. Find Iceland on the map. Hint: Look in the north Atlantic Ocean near Greenland. Iceland is bisected by the Mid-Atlantic Ridge. It is located at a divergent plate boundary where the North American and Eurasian Plates are moving apart! It is also on top of a mantle hotspot. This combo makes for a particularly dynamic volcanic landscape. Question 3.1 : Click on the volcanic eruptions and find the volcano named Katla. There are 15 entries for Katla that you can click through using the back and forward arrows on the info box. What type of volcano is Katla? Hint: Looking for the description listed in parentheses under the volcano name. Katla is a subglacial volcano. Question 3.2 : You are probably imagining that a volcanic eruption under a glacier could be a dangerous event and you would be right. Eruptions under glaciers can cause glacial lake outburst floods (jökulhlaup). View some helicopter footage of the April 14, 2010, glacial flood at Eyjafjallajökull: https://youtu.be/fJII-u-41Lg?si=u-wiMqRgZT6bSojC No other question here. Just write WOW! to confirm you have viewed the content. WOW! Question 3.3 : Watch a few minutes of the drone footage of an eruption in southwest Iceland on the Reykjanes Peninsula in 2021: https://youtu.be/b9Hq6bTBF2A?si=2KJgcTR2haredbta You see the lava flow across the surface and cool into new black rock. This lava is sourced from the mantle. What do you expect the rock composition to be? Hint: Think back to our discussions on mafic and felsic rocks . I would expect the rock composition to be mafic, characterized by high levels of magnesium and iron, resulting in the formation of dark-colored rocks such as basalt. References Global News (2021). “Iceland volcano: Drone footage captures stunning up-close view of eruption.” March 24, 2021. https://youtu.be/b9Hq6bTBF2A?si=VrGb5Ylf3G8Mr9u1 hp jobs (2010). “Eyjafjallajökull glacial flood (jökulhlaup) April 14th 2010.” April 14, 2010. https://youtu.be/fJII-u-41Lg?si=95UgDdXAHXgThhAP NASA (2002). Digital Tectonic Activity Map of the Earth: Tectonism and Volcanism of the Last One Million Years. DTAM – 1. https://eoimages.gsfc.nasa.gov/images/imagerecords/88000/88415/dtam.pdf The National Geographic Society, and Esri. MapMaker [software]. https://esri.com/mapmaker Page 4 of 4