Oh fair enough. That thought never crossed my mind. I kinda assumed if it starts leaning then gravity is only going to make it lean further. At least that's what it sounds like each time I read about it. But I don't know anything about structural engineering ¯\_(ツ)_/¯
No one really knows; it's built on landfill that used to be part of the bay and it isn't anchored to bedrock. However the rate of movement will most likely continue to slow over time and the foundation that is present will keep it from falling over anytime soon. Think Leaning Tower of Pisa, which sank and tilted slowly over many years... long enough for corrective measure to be take.
Fixing it will probably require cutting holes and driving down to bedrock, then pouring new concrete. It will have to be carefully done to avoid weakening the foundation and to make sure the new Piles don't poke through the concrete like a bed of nails.
The developer cheaped out... using reinforced concrete is less expensive than steel but it makes the building a lot heavier. Why the city let them skip out on anchoring to bedrock for such a tall building in an earthquake zone I have no idea. I do find it hilarious that all the other big towers going up are happily advertising their bedrock pillar work.
In the US, "reclaimed land" and "on top of literal garbage" are essentially the same thing. Discussion of that very thing is in this really interesting episode of 99% Invisible from last week: http://99percentinvisible.org/episode/making-up-ground/
