es ▁So - called ▁" Root less ▁con es " ▁are ▁caused ▁by ▁explos ions ▁of ▁la va ▁with ▁ground ▁ice ▁under ▁the ▁flow . ▁ ▁The ▁ice ▁mel ts ▁and ▁turns ▁into ▁a ▁v apor ▁that ▁exp ands ▁in ▁an ▁explos ion ▁that ▁produces ▁a ▁cone ▁or ▁ring . ▁Fe atures like ▁these ▁are ▁found ▁in ▁I cel and , ▁when ▁la vas ▁cover ▁water - s atur ated ▁substr ates . ▁ ▁M ud ▁vol cano es ▁Some ▁features ▁look ▁like ▁vol cano es . ▁ ▁Some ▁of ▁them ▁may ▁be ▁mud ▁vol cano es ▁where ▁press ur ized ▁mud ▁is ▁forced ▁up ward ▁forming ▁con es . ▁ ▁These ▁features ▁may ▁be ▁places ▁to ▁look ▁for ▁life ▁as ▁they ▁bring ▁to ▁the ▁surface ▁possible ▁life ▁that ▁has ▁been ▁protected ▁from ▁radiation . ▁ ▁Hell as ▁floor ▁features ▁Str ange ▁terrain ▁was ▁discovered ▁on ▁parts ▁of ▁the ▁floor ▁of ▁Hell as ▁Plan it ia . ▁ ▁Scient ists ▁are ▁not ▁sure ▁of ▁how ▁it ▁formed . ▁ ▁Ex hum ed ▁cr aters ▁ ▁Ex hum ed ▁cr aters ▁seem ▁to ▁be ▁in ▁the ▁process ▁of ▁being ▁un cover ed . ▁ ▁It ▁is ▁believed ▁that ▁they ▁formed , ▁were ▁covered ▁over , ▁and ▁now ▁are ▁being ▁ex hum ed ▁as ▁material ▁is ▁being ▁er oded . ▁ ▁When ▁a ▁cr ater ▁forms , ▁it ▁will ▁destroy ▁what ' s ▁under ▁it . ▁ ▁In ▁the ▁example ▁below , ▁only ▁part ▁of ▁the ▁cr ater ▁is ▁visible . ▁ ▁if ▁the ▁cr