Answer:
Paleomagnetism is the study of the record of the Earth's magnetic field preserved in rocks, sediment, and archaeological materials. When rocks form, their magnetic minerals align themselves with the Earth's magnetic field, preserving a record of the direction and strength of the magnetic field at the time of the rock's formation.
By analyzing the paleomagnetic data from rocks of different ages, scientists can reconstruct the history of Earth's magnetic field and its fluctuations over millions of years. This information can provide insights into the Earth's geologic history, including plate tectonic movements, volcanic activity, and climate change. Additionally, paleomagnetic data can be used to determine the latitude at which the rocks were formed, as the direction of the magnetic field varies with latitude.
As for the second question, the rate of Pacific plate motion at Kauai, Hawaii, is estimated to be about 7.5 centimeters per year. This estimate is based on a combination of GPS measurements and observations of volcanic activity and geological features in the region. However, it's worth noting that plate motion rates can vary over time and may not be constant over long periods.