Examine this map of the Lutgens Archipelago, a chain of ...

[KimWrice]

Examine this map of the Lutgens Archipelago, a chain of hot-spot-related islands atop the Tarbuck Plate in the Tasa Sea. Use the information given to determine the (a) direction and (b) rate of movement of the Tarbuck Plate.
 
  What will be an ideal response?

Question 2

Mount Hood (pictured) is part of the Cascade Range. These active volcanoes are a chain that stretches along the west coast from northern California to southern British Columbia, Canada. The Cascades are ________.
 
  A) evidence of subduction in the Pacific Northwest of the United States
  B) evidence of rifting of the North American continent
  C) a product of the San Andreas Fault
  D) due to a hot spot beneath Seattle

[ebe]

Answer to Question 1

Answer: Students will need to measure the distance from one island's volcanic center to the next, in kilometers, and use the dates for the lava flows in conjunction with the distance to calculate a rate. The plate must be moving toward the southeast over time, dragging the older islands off in that direction. The rate of motion is about 50 km/million years (or 5 cm/year). For instructors' reference, island 2 is 90 km from island 1 atop the hot spot (where the lava is erupting today), and islands 3 and 4 are 170 km and 220 km from island 1, respectively.

Answer to Question 2

Answer: A

[KimWrice]

Thanks for the timely response, appreciate it

[nathang24]

Gracias!