Miyamoto International Inc., a Sacramento global structural engineering firm, will move into downtown L.A.’s Aon Center skyscraper.

It sounds like the set-up for a joke: The earthquake mitigation company signed an 11-year lease to take roughly 10,000 square feet on the 51st floor of the 1.1 million-square-foot Class A building at 707 Wilshire Blvd. The lease is valued at roughly $4 million, according to Nathan Pellow, a senior vice president at Colliers International’s downtown office who represented Miyamoto along with associate James Robbins.

“They are earthquake engineers and are comfortable moving into the 51st floor of a high-rise, which makes me feel more comfortable about coming to the 35th floor of my building every day,” Pellow said.

At roughly $42 a square foot a year, Miyamoto landed a deal above the average $39.30-a-square-foot asking rate at Class A high-rise properties in downtown but below the rates of many new buildings which can reach the mid-to-upper-$40 range.

A high vacancy rate might have sweetened the deal. Pellow said because Aon is only 71 percent occupied, the landlord, San Francisco investment firm Shorenstein Properties, is aggressively trying to fill the space, which is only 71 percent occupied, Pellow said.

Richard Chen, a principal at Miyamoto, said the location near public transit and downtown’s center was key to the firm’s decision to relocate. It will move from its L.A. home of eight years at 700 S. Flower St. by November. It now has 20 employees in 5,800 square feet of office space.

“We are anticipating that our office will grow to 30 or 35 people in coming years, so we had to find a bigger space. And the view is awesome (at Aon),” Chen said.

Miyamoto plans to assemble an open layout in the space to make it collaborative, he said.

Tim Miller and Dana Vargas of Jones Lang LaSalle represented Shorenstein.

The brokers and Shorenstein could not be reached for comment.