The Jewish Remnant in Israel will be Protected
Isaiah 26:  Come, my people, enter thou into thy chambers, and shut thy doors about thee: hide thyself as it were for a little moment, until the indignation be overpast.  For, behold, the LORD cometh out of his place to punish the inhabitants of the earth for their iniquity: the earth also shall disclose her blood, and shall no more cover her slain.
At the very end of the Great Tribulation Period, during the last about 45 days, there will be Massive Volcanic Eruptions and Lava Flows throughout the world.
The 144,000 Jewish/Christian Believers in Israel will preach the Gospel to the Jewish people in the Negev Wilderness for 3 ½ years. During this about 45 day time period, they will hide themselves in the war bunkers in the Negev wilderness.
They will be allowed to enter into the Millennial Reign of the Lord Jesus Christ. All of the “True Christian Believers” will have been already killed by Earthquakes, Volcanoes and Tsunamis or Raptured at the 7th Trumpet, along with the 144,000 Jewish/Christian Believers; who will probably be mostly young Jewish men, similar to the Jewish men that the Lord Jesus Christ called during His personal ministry while He was alive on earth.
All of the rest of humanity will be non-believers, including children below the age of accountability and they will be going through a Global Volcanic Holocaust, as the majority of humanity will be burned off the surface of the earth as punishment for their iniquity; their immorality; their sinfulness.
Lava refers both to molten rock expelled by a volcano during an eruption and the resulting rock after solidification and cooling. This molten rock is formed in the interior of the Earth.
When first erupted from a volcanic vent, lava is a liquid at temperatures from 700 to 1,200 °C (1,292 to 2,190 °F).
The Holocaust (from the Greek ὁλόκαυστος holókaustos: hólos, “whole” and kaustós, “burnt”). The term holocaust comes from the Greek word holókauston, referring to an animal sacrifice offered to a god in which the whole (olos) animal is completely burnt (kaustos).