I live in a top floor apartment which is above the garage (open air, really just a lot). The unit is at the end of the building; the apartment is held up by columns. The building was built around the 1970s. During the last major earthquake in the area (Los Angeles, California), the building only sustained minor damage (a broken window).
The thing is, before I moved in, the landlord installed hardwood floors instead of the carpet that was there before (not a good idea). This has the effect of amplifying all kinds of sound waves and causing vibrations and thumps. There are moments when it's still, but when my next door neighbor (his apartment is also above the garage and has no unit below it) walks around close to my room (his bathroom is adjacent to my bathroom), his footsteps cause minor tremors to ripple through the floor. It's really annoying and it feels like I'm on a boat or in a car that's stopping and braking frequently. It happens in the kitchen and main room too (I live in a one-bedroom apartment).
I got an area rug and put some cut up carpet under the bed legs, and that seems to help a little bit as well as moving the bed away from the wall bordering the neighbor's apartment to the other side of the room. But I still feel the little ripples and shakes from time to time. Will soundproof foam pads under the carpet help?
It can't be that much of a structural deficiency; as I said before, the last major earthquake did not cause major damage to the building.
What can I do to soundproof my bedroom floor outside of stripping the hardwood and installing all the necessary things (can't afford that, landlord won't do it)? I'm pretty sure 99% of the vibrations are caused by my neighbor's footsteps. Perhaps some of it is caused by something else in the building, but this is hard to figure out due to having no unit below me.
My bed frame is also really cheap and flimsy and will shake and sway if you move around on it, so that's not helping. Should I take the headboard and mattress off the frame and just put it on the carpet? The couch in the main room also seems to ripple from time to time, but it feels more pronounced in the bedroom.
Other information: Since there is nothing directly below my apartment there are pipes immediately running underneath the floor and are visible in the garage. Could the pipes be causing the vibrations?