Every year, Nevada gets a little bigger.

Tectonic forces — movements that cause a change in the Earth's crust — expands the state’s surface by about two acres annually, or about the size of 32 tennis courts. Over millions of years, that has added up to a lot more surface area in the Nevada.

The USA TODAY Network spoke with Jim Faulds, state geologist and director of the Nevada Bureau of Mines and Geology, about why this happens. Here’s what we learned.

Growing on all sides

Nevada has been the fastest growing state for 20 million years.

How much has it grown?

If you stepped back in time 20 million years, the distance from present-day Reno, Nevada, to Salt Lake City, Utah, was only half as far as it is today.

And while the east side of California and the west side of Utah are expanding, Nevada is notable because the entire state is expanding. Northern and western Nevada are expanding more rapidly than the eastern and southern parts of the state.

How do we know the state is growing?

There are 400 GPS stations in the Great Basin region that measure movements in the Earth’s crust.

Active faults in the area allow for that movement, which often add land mass.

Where does that land mass come from?

Around the globe, portions of the earth are shrinking and contracting while others are expanding, again due to tectonic forces, Faulds said. That continual shrinking and expanding balances the Earth.

“That’s what make the Earth unique in the solar system," he said, "it’s always destroying itself and renewing itself.”

What do we do with the knowledge that the state is growing?

Knowing the state is expanding helps scientists estimate earthquake hazards.

The possibility of having an earthquake — and the magnitude of any earthquakes — is highest in western Nevada, although it’s not as high as along California’s San Andreas Fault.

What was the biggest earthquake ever in Nevada?

The largest earthquake to ever strike Nevada was in October 1915, when the Pleasant Valley earthquake ruptured the ground about 50 miles south of Winnemucca. The 7.3-magnitude quake left a scar more than 35 miles long.

The quake was felt as far away as San Francisco, Las Vegas and Salt Lake City.

USA Today