On the border between Israel and Jordan lies the Dead Sea, also known as the Salt Sea, due to its high salt content. This results from the way the lake was formed.
The story goes back to the days when Avram and Lot separated (Genesis 13), being too wealthy in livestock to inhabit the same area. Nowadays northern Israel is green, but the desert that begins just one mile south of Jerusalem makes California’s deserts look like oases! But this text speaks of the plain of Siddim being very well-watered like the Garden of Eden. This is the Jordan valley, in the area of the Dead Sea--certainly no place for livestock and no Eden! Apparently once it had an outlet, flowing all the way into the Gulf of Aqaba, and was a plain all the way down. Now all the salt and minerals carried by the Jordan simply build up there, and no fish can live in it since it is so salty. "Harvesting" them does, incidentally, provide one major source of income for Israel.
It seems the whole region of Sodom and Gomorrah just dropped like a sinkhole in a tremendous earthquake that pushed the mountains up to the south and west of the cities, blocking the outlet with a ridge now known to Arabs as Jabal Asdum ("Mountains of Sodom") and covering the scorched cities permanently with water. That the strata under the lake bed correspond with those of the mountains (really cliffs) on both sides (only much lower) has been confirmed by geological surveys. The land mass east of the plain shifted straight up, further exaggerating the depth of the sunken vale. Now this is a very deep lake (13,500 feet!) though it is narrowing due to evaporation, and its shores are the lowest land on the surface of the earth. They have large quantities of sulfur on the shores, reminding us that Yahweh rained brimstone on it.
But what caused the fire when the earthquake destroyed Sodom? Josephus tells us that the reason Sodom and Gomorrah became so corrupt was that they grew rich was through the trade of bitumen--the “tar”, or “slime pits” or “wells” that the Valley of Siddim was full of (Gen. 14). It is a black, flammable substance that can become viscous. The Jewish Encyclopedia says it was used for mortar and a sealant for ships, including Noah’s ark and the boat that carried Moshe through the bulrushes. They sold it to Egypt to use in mummification. It is the result of the evaporation and carbonation of petroleum. When mixed with other minerals (they poured vinegar on it), it becomes solid enough to cut into blocks for transport. In fact, there are so many chunks of it floating on the Dead Sea that the Romans called it the “Asphaltic Lake”. The Nabateans, Arab spice traders in Roman days, also became very rich and powerful through its trade. They were the ones who built the rock fortress of Petra.
Globs of asphalt occasionally ooze to the surface. They were very common until an 8th-century earthquake sealed off their source. In Josephus' day, this sea was called the "Asphaltic Lake". The Nabateans became wealthy selling these chunks of bitumin as a sealant for ships and as mortar (cf. Gen. 11:3). The desert sun sometimes set them ablaze, and because of the sulphur deposits nearby (the tinder for Sodom's demise?), it was called the "Lake of Fire and Brimstone", furnishing Y'shua with a perfect illustration of hell! The fact that it is 3,000 feet lower than Jerusalem (Zion)--the lowest place on the surface of the earth. incidentally--and that it has no outlet only add to the picture.
These pits were very flammable and explosive; this is how the city would have caught fire in the earthquake. The sea itself caught fire! It was highly combustible. Old maps show black spots on the Dead Sea. Oil seeps up from under it. There are also major sulfur deposits there. In fact, this may be what is referred to as the lake of fire and brimstone (Rev. 19:20) into which the Counterfeit Messiah will be thrown. It is only about 50 miles from Jerusalem, and the location where Azazel (the scapegoat), his prototype, was thrown was only 12 miles from Jerusalem. He won’t be able to dive under the fire, because everything stays afloat on the Dead Sea!
From similar seeps in Iraq, which were only “of slight commercial importance” in the early 1900s when the Jewish Encyclopedia was originally compiled, massive oil fields were later discovered. The Dead Sea itself does have an oily consistency. Until 200 years ago, there was massive seepage in the salt beds of S'dom (Sodom). They are still there, but an earthquake sealed them off in the 1800's.
If the earthquake when Messiah returns--Zech. 14:4-- reopens the fissures, it would probably set the lake ablaze again, making it possible for there to be a literal fulfillment of Rev. 19:20--that the Lamb throws the Beast and False Prophet ALIVE into the Lake of Fire! And the clincher is that, due to the high salt content in the lake, you cannot sink; you float on the surface. I've experienced it! It's effortless! So the two impostors will not be able to dive beneath the oil slicks as you could anywhere else. There will be no escape for them; they will die from it. (Daniel 7:11)
But Ezekiel 47 says that life will be brought back into the lake through the healing waters that flow out of the Temple of Yahweh, and the channel reopened.