How was the earth divided? (Gen. 10:25)

The Hebrew word erets (eh'-rets): is translated earth (600+ times) and land (1500+ times) ground (119). It is translated plateau (1), region (1), territories (1), floor (1), region (1), and territories (1).

Palag (paw-lag') is translated to split, divide.

Genesis 10:25New Century Version (NCV)

25 Eber was the father of two sons—one named Peleg,[a] because the earth was divided during his life, and the other was named Joktan.

Footnotes: a.10:25 Peleg This name sounds like the Hebrew word for “divided.”

Genesis 10:25Amplified Bible, Classic Edition (AMPC)

25 To Eber were born two sons: the name of one was Peleg [division], because [the inhabitants of] the earth were divided up in his days; and his brother’s name was Joktan.

Words in brackets were added by translator for clarification.

I don’t have a stringent opinion on this, but it seems to me that although the inhabitants or people were scattered or divided at this time, that other more specific words could have and would have been used.

However, God did tell them in 9:1 to grow in number and fill the earth which they didn’t want to do according to 11:4.

It is plausible that chapter 11 is explaining why and how the events of chapter ten.

It is also possible that changes in the land masses and water disburs*m*nt were occurring at this time from the catastrophic flood. Such changes would help keep the people separated.

When we compare verses 20 and 32 of Genesis 10 we see a similar notion of the division of the sons of Noah into nations, countries, and languages.

But verse 25 seems to be very different from the above-mentioned verses. The fact that Eber names his son Peleg (which means earthquake) and gave the reason why he names his son that name, i.e. "For the earth was divide פּלג (paw-lag) which means to split. This means that before the earth split there was an earthquake that divided the earth into different continents.

This tells us that before the floods, the earth was one continent surrounded by the sea/ocean then after God had made a covenant not to destroy the earth with floods, He brought the strong earthquake which split the earth into different continents and this created more space for water bodies. That in case of flood, reservoirs are prepared by God to contain it. What a wonderful God we serve; so loving, all-wise and He watches over His Word to perform it.

The explanation that I'm familiar with would indicate that this is referring to the division of cultures and tongues at the time of the Tower of Babel.

I can't take credit for the answer on my own. The explanation that makes the most sense to me is the one found here: http://www.answersingenesis.org/articles/cm/v22/n1/peleg

Four generations after Noah, Genesis 10:25 records the birth of Peleg (meaning division) ‘for in his days was the earth divided’. Some suggest the continents of the earth were divided at this time. However, this seems unlikely, as such a process would have had to occur within a very confined time period. The resultant geological violence would be overwhelmingly catastrophic—like another Noahic Flood all over again. Any continental separation thus likely occurred during the Flood. 1

The traditional interpretation, which seems more reasonable, relates this verse to the division of people/nations at the Tower of Babel event in Genesis 11. (Just like the English ‘earth’ can have a variety of meanings, the Hebrew erets can also mean nation(s)—thus erets Yisrael, the land (nation, people) of Israel.) According to the biblical chronology as deduced by Archbishop Ussher, the Flood occurred in 2349–2348 BC, and Peleg was born in 2247 BC about a hundred years later. Do ancient writers shed any light on when this happened? The answer is a resounding yes.

(Much more follows - visit the link for the full article).