The earthquakes that rocked Haiti and Chile this year were caused by the Earth's shifting tectonic plates, which float on the planet's molten core in constant sliding motion. Now, researchers have developed a new model of the Earth - two decades in the making - to predict the movement of one plate relative to another.
The model, called MORVEL for "mid-ocean ridge velocities," describes the relative movements of the 25 interlocking tectonic plates that cover almost the entire surface of the Earth. "Plate tectonics describes almost everything about how the Earth's surface moves and deforms, but it's remarkably simple in a mathematical way," said Chuck DeMets, a geophysicist at the University of Wisconsin-Madison.
DeMets worked with longtime collaborators Richard Gordon of Rice University and Donald Argus of NASA's Jet Propulsion Laboratory to build on their 1990 paper on tectonic plate velocities. Using higher-quality data developed over the past 20 years, the researchers updated their work in a paper available online and due for publication in the April issue of Geophysical Journal International.
"We live on a dynamic planet, and it's important to understand how the surface of the planet changes," Gordon said. "The frequency and magnitude of earthquakes depend upon how the tectonic plates move. Understanding how plates move can help us understand surface processes like mountain-building and subsurface processes like mantle convection."
The model can help scientists predict future tectonic plate movements. "Along the boundaries where plates meet there are lots of active faults," DeMets said. "It's useful to know how quickly the plates are slipping across those faults because it gives you some feeling about how often large earthquakes might occur."