My house was built in 1964 and seems well built for its age but after taking up carpet and refinishing the floors there are several high and low spots in the center of the house the stairs even have a slight angle to them.Its a two story house that has a 3/4 basement that has a supporting wall made of cinderblock though the middle length in the basement. We live in an area that is solid limestone and my neighbor said my house was supposed to have been a full basement instead of part crawl space but blasting the rock was a problem at the time. We also live near a quarry that sets off explosions once a day (usually very late at night) this rattles the windows and makes things shake slighty. Its a little like living by an airport or near train tracks , no one seems to notice after a while, but my imagination is saying its like a little earth quake once a day and this maybe some of it. Should I have someone inspect this(who)? Or am I worried about normal settling? Are there any guidelines when its a good idea to call in experts?Any advice is greatly appreciated!