Plate Boundary Observatory (PBO)
Have you ever felt the jolt of an earthquake or heard the rumbling of a volcano? Both are caused by slowly moving tectonic plates as they chug along at the rate your fingernails grow: several centimeters per year. The PBO measures how far and how fast the Earth's surface moves under each instrument
Question 1:
What is a plate boundary?
Question 2:
Why do tectonic plates move?
An Example GPS Station Plot
This simplified time series plot is a record of a GPS unit having moved about 20 millimeters (0.79 inches) over a three year period. (Click the image for more information.)
Explore the instruments PBO uses to monitor Earth's Motion