Vocally and lyrically she often presents herself as a castaway - an isolated human on a strange shore shouting out across the waves in volcanic bursts of anger and exhilaration, and then creeping into a cave to comfort herself with childlike lullabies.
Her last album, 2004’s Medulla, saw her sub-aquatic. On songs such as Oceania and Submarine, she created a soundscape entirely composed of human voices. Released two years after the birth of her daughter, it had a soothing amniotic quality.
And now the beats are back, inspired by more big-scale geography. In January 2005, shortly after the Asian tsunami, the Icelandic madcap made a trip to Indonesia on behalf of Unicef. She was shocked by the force of the event.
"The tsunami just scraped houses away," she said. "You could still see the floor and the people I was with found their mum’s favourite dress kind of in the mud and it was just like, outrageous."
The experience led to a fantasy that "Maybe a tsunami of people would just come and hit the White House and scrape it off the ground and do some justice and spread these people all around the planet." The resulting sound is fiercely, ecstatically tribal : the sound of parties around beach fires.
Over a broad footsteps-on-gravel beat (a collaboration with R&B producer Timbaland), she sings shaman-like of being one of the "Earth intruders/muddy with twigs and branches" bringing "necessary voodoo" and "voltage", "grinding the sceptics into the soil".
It’s characteristically bold stuff, and Volta stays the course, evolving into a pagan symphony of foghorns, brass sections and bells. Malian kora master Toumani Diabaté adds beautiful - almost bioluminescent - sprinkles of delicate plucking, while Antony Hegarty (of Antony and the Johnsons) provides rich, smooth, melancholic eddies of vocal in a lovely contrast to Björk’s own more seismic style.
It should have the ground shaking all summer.