Using the power of Google Earth, GeoTours take you on flyovers of key locations discussed in the text.
StudySpace student website and ebook icons in each GeoTour connect your to the text and online review materials.
Dialogue boxes accompanying each site include text, figures, photos.
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Geotour 8: Seismically Active Faults
Evidence of Earthquake Activity along a Plate Boundary (San Andreas transform fault)
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| 1a. Check and double-click the placemarks for Problem 1a to fly to the Wallace Creek area along the San Andreas fault in California. Also, in the Layers panel, turn on Gallery > Earthquakes.
Use the Measuring Tool to determine the distance (in m) that Wallace Creek has been offset by recent motion along the San Andreas.
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| 1b. Assume that the present rate of slip along the fault is about 6 cm/yr. How many years has it taken to develop the observed offset of the stream?
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| 1c. What is the sense of offset along the fault (i.e., Walk along either segment of Wallace Creek toward the fault. At the fault, determine the direction you turn to find the offset segment of the stream across the fault.)?
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| 1d. Use the Measuring Tool to determine the orientation (in degrees) of this segment of the San Andreas fault (the first number is relative to north on a compass and the second number is relative to south on a compass [ranging from 000° to 360°; e.g., 045°-225° is a line oriented NE-SW]).
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| 1e. Check and double-click Problem 1e to fly to the Palmdale area of the San Andreas fault. What type of lake is this (one that forms in a depression along a fault trace)?
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| 1f. Check and double-click the placemarks for Problem 1f to fly to another offset stream along the San Andreas. Use the Measuring Tool to determine the distance (in m) that the stream has been offset and then use the present rate of slip along the fault (6 cm/yr) to determine how many years it would take to cause this much offset along the fault.
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| 1g. The physiographic trace of the San Andreas fault passes through the San Francisco/Oakland area and then skirts the shoreline for some distance to the northwest. Check and double-click Problem 1g to fly to the coastal area near Fort Ross. Which of the statements is incorrect?
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Evidence of Intraplate Earthquake Activity (New Madrid, MO)
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| 2a. Turn on the “New Madrid, Mo Seismicity” map overlay and double-click it to fly to the Missouri, Illinois, Kentucky, Arkansas, and Tennessee areas. Also, in the Layers panel, turn on Gallery > Earthquakes. This area is well within the North American plate, yet it has a surprising number of earthquakes (you may recall that this area was the site of three magnitude 8.0-8.5 earthquakes during the winter of 1811-1812).
What is the dominant trend/pattern of earthquakes in this region (i.e., what direction would you assume that most of the faults are oriented)?
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| 2b. What is the best explanation for this intraplate seismicity?
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| 2c. On the overlay, there is a concentration of higher magnitude earthquakes (blue dots) near New Madrid, MO (location of the early 19th century large earthquakes). Which statement is the best hypothesis to explain this observation?
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Stress Transfer and Earthquake Prediction (North Anatolian Fault, Turkey)
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| 3a. Check and double-click the “North Anatolian Fault, Turkey” placemark in the Problem 3 folder to fly to northern Turkey. Also, in the Layers panel, turn on Gallery > Earthquakes. The figure within the placemark shows a historical summary of earthquake activity along the North Anatolian fault (including the segments of the fault that were active during each event).
What is the dominant pattern of major earthquakes along the North Anatolian fault from 1939-1967?
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| 3b. If a pattern exists, what might cause this pattern?
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| 3c. In the lower figure of the placemark, look at the segments of the North Anatolian fault that have slipped (ruptured, white) versus those that have not ruptured recently (black). Where would you predict future earthquakes along this fault?
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Tsunami Devastation (Banda Aceh, Sumatra)
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| 4a. Check and double-click the “Regional Plate Tectonics” map overlay and the Epicenter placemark in the Problem 4 folder to fly to the Sumatra region that was devastated by a tsunami in late 2004. Also, in the Layers panel, turn on Gallery > Earthquakes and Gallery > Volcanoes.
Which tectonic plate was subducted beneath which overriding tectonic plate at this locality to produce this massive earthquake?
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| 4b. Check and double-click the Tsunami Travel-Time Animation placemark in the Problem 4 folder. How long did it take the tsunami to first arrive at Sri Lanka across the Indian Ocean?
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| 4c. Use the Measuring Tool to determine the distance from the earthquake epicenter to
placemark Problem 4c on Sri Lanka in (km). Use your answer from part b to determine the average velocity at which the tsunami traveled across the Indian Ocean (km/hr).
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