the smooth, undulating surface of frozen pahoehoe lava

abstract active ash autumn background backgrounds bark basalt beautiful big black caldera cliffs clinker closeup cooling detail dramatic eruption fern field flat flow fold forest form frozen garden geology grass grow growth hawaii hilo island ivy kilauea lava leaf leaves life macro magma mountain natural nature new old outdoor pahoehoe paradise pattern plant rock rough smooth spring sprout stone summer surface texture textured tourism travel tree trip undulating view volcanic volcano wall wood wrinkle