Estimation: Around 96 million tonnes of waste would be instantly generated,they
used the word
around hence suggesting that it was estimated.
Approximately:471,000 homes and buildings would be destroyed, most of them
by fires, or
because of liquefaction, a process where reclaimed land turns to mush.
Explaination: As the result of the no. of homes destroyed is still unknown, it
shows that it is approximated.