[Just mythoughts]

Well we are not told specifically other than flooding what other types of what we call natural disasters took place in Genesis 1:2. However, this earth is marked with all manner and types of 'natural' disasters and we even can see the remains of life that was destroyed eons ago. Also we are told in Genesis 2:5 And every plant of the field before it was in the earth, and every herb of the field before it grew:

for the LORD God had not caused it to rain upon the earth, and there was not a man to till the ground.

This is after the 7th day of rest that the earth was 'watered' without rain. So all that water of Genesis 1:2 had to go someplace.

[dr_lew]

So all that water of Genesis 1:2 had to go someplace.

In Genesis 1:7 God divides the waters and creates the firmament, which should not be confused with the common notion of "firm ground". The firmament, ( See Webster's ) means "The vault or arch of the sky," and it created a protective enclosure within the waters of chaos.