roughly how fast do most lithospheric plates move?
Most lithospheric plates move at a rate of a few centimeters per year. The movement of lithospheric plates is referred to as plate tectonics, which is driven by the convective flow of the underlying asthenosphere.
To determine the speed at which lithospheric plates are moving, scientists use a variety of techniques. One common method is called GPS (Global Positioning System) measurements, where GPS satellites are used to track the movement of specific points on the Earth's surface. By continuously monitoring these GPS points over a period of time, scientists can calculate the distance moved and therefore determine the plate's velocity. This method provides accurate measurements of plate motion.
Another technique is based on the study of paleomagnetism. Throughout geologic history, Earth's magnetic field has periodically reversed, leaving a record in the rocks. By determining the orientation of the paleomagnetic signature in different rock formations, scientists can estimate the past positions of the continents and the rate at which they have moved over time.
Additionally, geologists analyze features such as mid-oceanic ridges, transform faults, and hotspots to indirectly measure plate movements. For example, by measuring the rate of spreading at mid-oceanic ridges or the rate of offset along transform faults, scientists can estimate the average velocity of lithospheric plate motion.
Overall, while the speed at which lithospheric plates move varies between different plate boundaries and locations, the average rate falls within the range of a few centimeters per year.