Experts say the city of Houston has sunk by two centimetres due to the amount of rain that fell during Hurricane Harvey.
NASA geophysicist Chris Milliner says the earth's crust "flexed" under the weight of widespread floodwaters.
He says the effect will reverse once the water recedes, comparing it to bouncing on a mattress.
Meanwhile, Senate Republicans have almost doubled the size of the disaster relief package for Storm Harvey to more than $15bn.
The first instalment aims to help communities in Texas rebuild from the storm - and stock reserves for looming damage from Hurricane Irma.
The legislation, paired with a short-term increase in the government's borrowing authority and a temporary government funding bill, is on track to pass the Senate.
The federal government's disaster aid reserves are rapidly dwindling as Irma takes aim at Florida.
Senate majority leader Mitch McConnell unveiled the measure late on Wednesday, adding $7.4bn in community development block grants to President Donald Trump's $7.9bn request, which overwhelmingly passed the House on Wednesday.
Mr McConnell also added a temporary extension of the federal flood insurance programme.
"It will provide certainty and stability for first responders, state officials, and the many others involved in preparing for and recovering from these storms, with critically needed emergency resources that will not be interrupted by the prospect of a shutdown or default," Mr McConnell said.
"The recovery effort for a record-setting storm like Harvey has strained resources to the limit already."
The additional community block grant money is to jump-start rebuilding efforts. The money can cover costs the Federal Emergency Management Agency (Fema) cannot.
The $15bn aid package is crafted in such a way to free up another $7bn in Fema disaster relief funds.
The Senate vote came a day after Mr Trump shocked Republican leaders by siding with top Democrats Chuck Schumer and Nancy Pelosi, who demanded a debt ceiling increase only until December.
House speaker Paul Ryan, who opposed the short-term debt limit, said on Thursday that the deal Mr Trump cut with Democrats made sense, with one devastating storm and another looming.
Mr Ryan said the president did not want to have "some partisan fight in the middle of the response".