Poet and professor Craig Arnold went missing on a Japanese island three days ago where he had gone to see a local vollcano.
Arnold, a volcano enthusiast and professor at the University of Wyoming in Laramie, has visited many volcanoes around the world and written poems and essays about them.
Professor Peter Parolin, chair of the English Department at the university, says Arnold has always been attracted to extreme places.
"For Craig, poets go and should go where most of the rest of us don't," he says.
The search for Arnold, which went on for three days, has been extended for another three, Parolin says.