 In spite of their fresh appearance , the oldest flows in the Craters of the Moon Lava Field are 15 @,@ 000 years old and the youngest erupted about 2000 years ago , according to Mel Kuntz and other USGS geologists . Nevertheless , the volcanic fissures at Craters of the Moon are considered to be dormant , not extinct , and are expected to erupt in less than a thousand years . There are eight major eruptive periods recognized in the Craters of the Moon Lava Field . Each period lasted about 1000 years or less and were separated by relatively quiet periods that lasted between 500 and as long as 3000 years . Individual lava flows were up to 30 miles ( 50 km ) long with the Blue Dragon Flow being the longest . 
