4.2 The Earth Moves
In this section of the assignment, you will examine seismic and volcanic activity patterns around the world relative to tectonic plate boundaries, physical features on the earth’s surface, and cities at risk. By the end of this section, you should be able to:
- Locate zones of significant seismic or volcanic activity.
- Describe the relationship between zones of high seismic or volcanic activity and tectonic plate boundaries.
Where are global earthquakes located?
Step 1: Go to the ArcGIS Online map, Earth Moves, and explore the map.
Step 2: Examine the yellow dots on the map that represent earthquakes with a +5.7 magnitude.
- What spatial patterns do you see on the map?
Where are the most significant earthquakes on Earth?
Step 3: With the Details button depressed, click the button, Show Contents.
Step 4: Click the Earthquakes Magnitude 5.7+ layer name, and then click the Show Table button.
Each record in this attribute table represents one point on the map.
Step 5: Click the Magnitude column heading (field) and choose Sort Descending.
Step 6: Highlight the first 20 records (highest magnitude earthquakes). In the table, click a feature in the list to see it highlighted in the map. To select multiple features, press the Shift key and click each feature that you want to highlight.
- Where are the blue highlighted high-magnitude earthquakes located on the map?
Where are the active volcanoes on Earth?
Step 7: In the top-right corner of the table, click the X to close the table.
Step 8: In the Contents pane, uncheck the Earthquakes Magnitude 5.7+ layer box to turn off the layer and turn on the Volcanoes – Active Only layer.
- The observable spatial patterns are that earthquake and volcano locations line up in similar patterns except for the volcanoes in some areas of Africa and the north Pacific Ocean. (T/F)
Where are tectonic plates relative to physical features on Earth?
- Based on the locations of earthquakes and volcanoes, where do you think the tectonic plate boundaries are?
Earth is always changing. The crust of the earth includes several tectonic plates that are always on the move. The effects of movement are most noticeable at the boundaries between tectonic plates.
Step 9: Turn off the Volcanoes – Active Only layer and turn on the Earth’s Tectonic Plates and Major Physical Features layers.
- There are many tectonic areas where physical features, tectonic plate boundaries, and seismic and volcanic activities overlap. They include the eastern part of the map where the Philippine and Pacific tectonic plates meet, eastern Africa, the Mid-Atlantic Ridge, and the western coast of North and South America. NOTE: Turn on earthquakes and volcanoes if needed. (T/F)
Where might there be higher-risk areas for seismic or volcanic activity?
Step 10: Turn off all layers except Major Cities, Continents, Earthquakes, and Volcanoes – Active Only.
Step 11: Pan and zoom the map to find cities near an earthquake or volcano.
- Name three cities and the area in which they are located.