Lab #12 - Earthquakes and Subduction Boundaries Cover Page 1. Problem Statement: What is the relationship between the age of a tectonic plate and the rate of its subduction? 2. Hypothesis: 3. Experiment a. Materials: b. Procedures: 4. Data: Earthquake Summary Earthquake Type Shallow
Earthquake Depth
Tonga Total
Chile Total
< 70 km
Intermediate
70-300 km
Deep
> 300 km Total Number of Earthquakes
5. Analysis: 1. Locate Tonga on a map. Which plate is subducting? What plate is it subducting under? 2. Locate Chile on a map. Which plate is subducting? What plate is it subducting under? 3. Locate the East Pacific Rise on the map. Is Tonga or Chile farther from the East Pacific Rise? 4. The East Pacific Rise is a mid-ocean ridge, where new oceanic crust is formed. Based on the distance from the ridge, is the subducting plate near Tonga younger or older than the subducting plate near Chile? 5. Look at the values in the Earthquake Summary Table. How does the depth of the majority of the earthquakes at Tonga compare with those at Chile? 6. Look at the graphs. The lines represent profiles of the subducting plates for the two areas. a. In which area is the subducting plate moving westward? b. Which plate is subducting at a steeper angle? 7. For the Chile data region, the deepest earthquake occurred at longitude 61.7W and at a depth of 540 km. If the rocks at that earthquake began subducting 10 million years ago, and are now 1000 km from their original position, what is the average rate of descent (in cm/year) of the subducting plate? Show your work to receive credit. 8. Would you expect the rate of subduction at Tonga to be greater or less than the rate at Chile? Explain your answer. 6. Conclusion: 1. Summarize the differences between the subducting plate at Chile and Tonga by comparing the following: a. distance from the mid-ocean ridge b. age c. angle of descent d. number of deep earthquakes
Background: Most earthquakes occur at plate boundaries. The deepest earthquakes occur at subduction boundaries where the lithosphere is plunging down into the mantle. Deep earthquakes are defined as having a depth of 300 km or more. Shallow earthquakes are less than 70 km in depth. Earthquakes between 70 km and 300 km are considered to have moderate depth. Behavior of a subducting plate is determined by the age of the rocks composing the plate. Older crust is cooler and therefore denser than younger crust. Older, cooler, denser crust subducts faster and at a steeper angle than younger, warmer, less dense crust.
Procedures: 1. Count the number of shallow earthquakes (less than 70 km) for both Tonga and Chile. Record your values in the Earthquake Summary Table. Repeat counting the number of intermediate and deep earthquakes for each area and record your results in the summary table. 2. Add the numbers in both columns of the Earthquake Summary Table and record your results. 3. Plot the data from Tonga on the Tonga graph and plot the data for Chile on the Chile graph. 4. Do not connect the dots. Instead, draw a best-fit line for the points. A best-fit line is a single line that shows the trend of the data without having to pass though all points. 5. Assume the line you have drawn is the upper surface of a subducting plate. 6. Complete the analysis and conclusion questions.
Critical Infrastructure and Urban Resilience. April 21, 2015 .... University of Canterbury (Dr. S. Giovinazzi; Dr. D. Hart, & others). â« Japan. â« Japan Society of Civil ...
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[1] Our 3D modelling study shows that the presence of lithospheric plates around a subducting plate has a significant influence on subduction dynamics, in particular on trench retreat rate, slab dip, and lateral shortening of the subducting plate. Ne
O STRUCTURES O Time : 3 hours Maximum Marks : 70. Note : Attempt any five questions. All questions carry equal. marks. 1. (a) Describe the Earth's structure ...
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significance. 10. b) What is the significance of moment magnitude scale of measuring an. earthquake ? During a major earthquake, the depth of fault rupture was.
4Faculty of Earth and Life Sciences, VU University, Amsterdam, Netherlands, ... of Geological Engineering, Middle East Technical University, Ankara, Turkey ...... Hawkins, J. W., S. H. Bloomer, C. A. Evans, and J. T. Melchior (1984), Evolution of ...
Oct 23, 2012 - Both geophysical and petrological data suggest that large amounts of water are released in subduction zones during the burial of oceanic lithosphere through metamorphic dehydration reactions. These fluids are generally considered to be
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Consequently, a strong public interest exists in Minnesota regarding. earthquakes, as does some concern about the ... example, the deadly 1994 Northridge earthquake near Los Angeles occurred. along a previously unknown off-shoot of the .... Red Lake
catastrophic release of years of built up stress, triggering a magnitude 9 earthquake â the largest ever. recorded near Japan, and the fifth largest every recorded anywhere on Earth. In less than 2 minutes, literally hundreds of thousands of cubic
Retrying... Whoops! There was a problem previewing this document. Retrying... Download. Connect more apps... Try one of the apps below to open or edit this item. EARTHQUAKE PROTECTION OF Non--Structural Elements in Buildings.pdf. EARTHQUAKE PROTECTIO
