"Whatever affliction that may visit you is because of what your hands have earned, and He excuses many [an offense of yours]." - (Qur'an 42:30)
This verse does inform the wrongdoers about the result of their bad deeds, but it does not suggest at all that all the natural disasters are results of human actions.
In some cases mentioned in Quran and authentic Hadeeths, natural disasters came on sinners who insisted on major sins, like people of Noah and people of Loot, but not all the natural disasters are same. Natural disasters can fall on Muslims and non Muslims, which means that it is not always a punishment. It is related to natural factors and reasons created by Allah (SWT) who created the Universe. Even those innocents who suffer from natural disasters will not be let with out appropriate compensation from Allah which is much greater that their loss. Those innocents who die from natural disasters will be granted much better and happier life.
The Mercy of Allah is greater than any suffering whatsoever.