In the early 20th century, Alfred Wegener developed a theory of continental drift, indicating that the continents of Earth move and were in different positions than they are currently.
In the 1960s, scientific discoveries about seafloor spreading, combined with earlier theories of continental drift, led to a theory of plate tectonics.
According to the theory of plate tectonics, Earth’s lithosphere is made of plates that move and cause changes to crustal features at plate boundaries.
Features on Earth’s crust can be observed as consequences of plate tectonics. A convergent boundary occurs when two plates collide. Depending upon the type of crustal material at the boundary of the colliding plates, volcanoes, mountains and ocean trenches can form. A divergent boundary occurs when two plates move away from one another creating rift valleys in continental material and ridges in ocean basins. A transform boundary occurs as two plates move past each other causing faulting and earthquake activity.
Mountain ranges, volcanoes, rift valleys and other land features can be observed from space, and these images can be used to support theories about tectonic plate activity.
Topographic maps can be used to examine the elevation of an area. The elevation can be measured and monitored for changes over time.
Satellite technology allows scientists to photograph land and erosional features and study them for changes over time.
Evidence of changes that occurred in the past can be observed from space, allowing scientists to predict changes that might occur in the future due to sediment deposition, glacier movement, and river courses.