The China Earthquake and Plate Tectonics

Name: _________________________________       Date: _____________

On May 12, 2008, China's Sichuan Province was jolted by a devastating earthquake of magnitude 7.9. Unlike most quakes, which usually strike near the edges of tectonic plates, the Sichuan quake hit hundreds of miles from the nearest plate boundary.

Although less frequent, quakes can and do strike far from plate boundaries. Huge amounts of stress build up along mid-plate faults just as along plate boundaries. In fact, scientists at the Center for Earthquake Research recently predicted Sichuan was due for a big quake. In this Planet Diary activity, you'll find out why they weren't surprised when the quake hit. You'll also explore how widely the shaking was felt and where it was most violent.

1. First, read Planet Diary's Journal Entry Deadly Quake Jolts China. Study the map and read the caption. What does the red line southwest of the epicenter show?
   
   
   
   
2. What happens along this line?
   
   
   
   
3. Read the second to last paragraph. Describe how stress created along the Indo-Australian and Eurasian plate boundary builds up in China's Sichuan Basin.
   
   
   
   
4. Take a look at a NASA elevation map of the Sichuan Basin. What do the green and beige colors show on the map?
   
   
   
   
5. What do the red circles show?
   
   
   
   
6. How close in Chengdu to the largest circle (the magnitude 7.9 quake)?
   
   
   
   
7. The circles are clues to the location of the Beichuan Fault where scientists recently found great stress building up. Describe the fault's location relative to the Tibetan Plateau and mountains (to the west) and Sichuan Basin (to the east).
   
   
   
   
8. Scroll to the third paragraph. What causes most earthquake activity in central and eastern Asia?
   
   
   
   
9. How does the collision of the two plates lead to stress on faults along the Sichuan Basin?
   
   
   
   
10. View this earthquake Intensity Map to see how widely the quake was felt. Look at the color key and map scale. About how far from the epicenter was strong shaking (Intensity VI) felt?
    
    
    
    
11. How far from the epicenter was weak shaking (Intensity II or III) felt?
    
    
    
    
12. For a closer look, check out this earthquake Shake Map near the epicenter. Name the cities most at-risk to violent or extreme shaking.
    
    
    
    
13. View this Population Map. Study the population exposure table and map. About how many people were exposed to violent or extreme shaking (Intensity IX or X)? Note that "k" represents 1,000 people.
    
    
    
    
14. How many were exposed to strong shaking of Intensity VI or higher?