Rate of Movement of the Pacific Plate Using Hot Spots

Using the map of Hawaii and the Emperor Seamounts below, complete the following questions about the Hawaiian-Emperor island chain. Ages are shown in millions of years in parentheses. An example and explanation are provided to help you answer the questions.

Example: What is the distance from Midway Island to Lo’ihi in km? What is the difference between their ages? What has been the rate of movement of the Pacific plate, in cm/yr, over this time frame?

Answer and Explanation:

The distance is approximately 2400km (If you do not know where this number came from refer to the Map Lab from chapter 1 it explains how to get distance from maps).

Midway is 27.7 myrs old (myrs stands for millions of years) and Lo’ihi is zero years old (It is forming today) so the time frame will be 27.7 myrs -0 myrs = 27.7 myrs

Rate = distance/time so, 2400km/27.7myrs = 86 km/myrs

Next you need to convert to mm/yr and you get 86mm/yr (when you convert km/myrs to mm/yr all the zeros cancel out and you get the same number), then convert to cm/yr by dividing by 10 (there are 10 mm per 1 cm, refer to the math skills lab in Chapter 1 if you do not remember how to convert).

86km/myrs = 86mm/yr➗ 10 = 8.6 cm/yr

Questions:

1. What is the distance to the Suiko Seamount to the Koko Seamount, in km? What is the difference between their ages? What has been the rate of movement of this region of the Pacific plate, in cm/yr over this time frame?

2. What has been the rate of movement for the Pacific plate between the Abbott Seamount and Lo'ihi in cm/yr?

3. What has been the rate of movement for the Pacific plate between the Suiko Seamount and Lo'ihi in cm/yr? You should measure the distance between the Suiko Seamount and the Daikakuji Seamount and then measure the distance between the Daikakuji Seamount and Lo'ihi and add them together for the total distance.

4. Has the rate of movement of the Pacific plate been constant over the lifetime of the Hawaiian-Emperor island chain? Which section has been moving faster?

5. The oldest rocks that make up Lo'ihi is an estimated 400,000 years old. Using the rate of plate movement that you calculated in question #2, how far has it traveled in km since its first lava cooled? Hint: you need to rearrange the rate formula to determine distance and then convert cm to km. Rate=distance/time so distance= rate x time.