Was it an earthquake?

Was it a giant stomping on the roof?

Or did a truck ram into the building?

None of the above. But until the two loud booms just before 2 p.m. were explained, those were all logical explanations. A common sight Tuesday afternoon was to see others pouring from buildings, trying to figure out what happened.

The two rapid-fire explosions were really sonic booms from two military jets scrambled from Portland after a general-aviation airplane intruded into closed airspace soon to be traversed by President Obama, according to media reports.

The Cessna 150 involved in the intrusion landed at Kenmore Air on Lake Washington, according to the company’s general manager Todd Banks.

“The airplane is moored at our place. He was returning from a long weekend trip from his cabin in Chelan. He has made the same round-trip flight for years. He was unfortunately unaware of the TFR (temporary flight restriction),” Banks wrote in an e-mail to the Reporter.

According to KING5.com, the pilot is Lee Dailey, who was flying with his passenger, Laura Joseph.

Obama was in Seattle for a campaign fund-raising event for Sen. Patty Murray of Bothell. He was to depart from Boeing Field.