you are watching the kilowea volcano creating new land as it destroys old land. these are pictures of what was the world famous black sand beach on the big island of hawaii. the beach doesn't exist anymore. it's now buried under 75 feet of harden lava. just eight months ago this house was at the edge of that beach look at it now. more than 1/3 of a mile from the new lava shoreline. >> when you have a lava flow it changes completely. you can go stand out there and say, now, where was it? i mean where was my house? you can't tell. >> reporter: long lava tubes that form right underneath cooled lava flow are carrying molten rock all the way to the ocean. >> it gets here by a tube about 7 miles long. comes right on down the slope and it's insulated. that's the only way it can remain liquid. 200,000-degrees. >> so it's covered until it gets to the ocean. >> right it formed its own tube. until it gets to the ocean. >> reporter: flying up slope over hardened lava you can sense the 12-foot diameter tubes underneath. steam escapes through cracks in the sheets of black rock