if a sonic boom occurs in the sky what does it sound like from the ground?

   Today president Obama visited my favorite place in seattle, pikes place market. At the same time i was visiting my grandmother 30 miles south of the city, and a cessna 180 coming from eastern washington entered low into restricted air space causing the military to quickly dispatch 2 F-15's (fighter jets) to intercept the plane and assertain if it was a threat or not. my sister, grandmother, dog and i were sitting in the living room chatting, unaware of the potential threat when all of a sudden there was a loud BoOOOoM! as if something heavy had fallen on the roof over our heads. the house shook and windows rattled like in a small earthquake. we shot straight up, the dog started barking, "what the F**K was that?!!!?!" we asked eachother (remembering a small plane crash that happened awhile back) and ran to the back yard to see if anything had landed in the yard. we looked out over the backyards into the distance still hearing dogs and birds barking and sqwaking in alarm when a second BoOOOoM!!!!! occurred. It honestly sounded like something exploded only 100 ft away from us. But still we saw nothing out of the ordinary. we walked back inside and with nothing on the news to explain the low flying plane situation, quickly forgot about the incident. later when my mother came home she asked if i heard the sonic boom of the 2 fighter jets flying overhead. "THATS what that was?!" i exclaimed as she filled me in on the news.

   Those two explosions i heard were the sonic booms of the F-15's sent to save the day. They flew from Portland Oregon to Seattle Washington in T-E-N minutes.