Stepping on thunder to see the world's most accessible live volcano

Guide Marc Giraud's question is rhetorical, I hope, because I don't have an answer for it. The world's most accessible active volcano is here, on Tanna, but I'm part of the first tour that makes it less accessible.

Giraud is studying a map he's printed from Google Earth. There are lines in pen crossed off; but there's one in red we seem to be following. Four-wheel-drives pass us on their way to Mount Yasur, along narrow roads cut through thick volcanic ash. We're the only ones on foot, aside from a group of locals carrying sling shots to shoot flying foxes for dinner. Those in vehicles can drive right to the rim of the volcano ... but we're taking the slow road.

Captain Cook was the first European to discover Mount Yasur; its glowing light attracted his ship here in 1774. Yasur has been exploding lava into the air every day for a millennium. Underneath us, the Indo-Australian tectonic plate moves east, while the Pacific plate shifts west - the friction creates one hell of a hot spot.

We're walking across a moonscape mostly devoid of vegetation, led by a little bloke in bare feet, carrying a grapefruit and an umbrella. His name is Daniel Walgain, he's a local, it was his idea - together with Giraud - to make one of the world's once-in-a-lifetime travel experiences even more memorable.

As we walk, the volcano booms, shaking me in my boots. We cross a shallow river, then walk through jungle to a tiny village that appears to be ruled by pigs. This is Green Point, the centre of the John Frum cargo cult. Tanna is an island of customs and legends; locals stick to tradition more than on any other island in Vanuatu.

Green Pointers believe a man (Frum) stepped out of the bushes here in the 1930s offering them great prosperity if they threw away their bibles and returned to their old ways. And so they did ... but so far they haven't got rich.

I'm taking cover beneath a shelter in an outdoor ash quadrangle with the chief as a rainstorm hits. He dances here each Friday night till dawn, enticing Frum to return. I ask the chief how he knows we're safe here from an eruption (the village was last evacuated in 2008).

''The volcano is my grandfather,'' he says. ''He will tell us if we have to leave.'' Grandpa belches loudly and the earth below moves. When the rain stalls, we push on through thick forest - Walgain slicing through it with his machete.

I smell methane now, and daylight is waning so the show is starting: a light display from seven kilometres below. I trudge through ankle-deep ash to the summit, and stare down at a 400-metre-wide crater where lava the size of cars launches hundreds of metres into the air around me. I watch the Earth explode below me till the stars shine above and the wind changes, and Walgain orders me off his mountain as the exploding cars get closer and closer.

We won't go far though, just to a treehouse down the road (with a perfect view of Yasur) that shakes and shudders through the night with every explosion. Next day we take to 4WD trails no car should rightly conquer and when the corrugations get too severe, we hike to hot springs set on sand by the ocean on a bay with no one on it (this is Port Resolution, where Captain Cook came to explore Yasur).

I notice the only travellers who linger on this east coast are backpackers; other tourists tend to fly in and out, driving straight to Mount Yasur, then back again. And it gets me thinking: why would you drive up a live volcano when you can hike up it?

Craig Tansley travelled as a guest of Vanuatu Tourism and Air Vanuatu.