“What you’re going to be hearing in Haleakala,” Gordon Hempton, a Grammy-winning natural-sounds recording artist had told me, “is just a sense of presence, a low frequency that the ears will not be aware of but the body will measure, arising from either deep in the earth with the volcano or the distant ocean surf.”

Although during its last eruption sometime in the past 500 years, Haleakala might have blown more than 250 decibels (enough to turn living things into soup with its very sound wave), no one knows precisely how quiet it is today. At certain places on the crater floor, says Liz Gordon, the cultural resources manager for Haleakala National Park, “It gets so quiet, it exceeds the technical capabilities of the microphones.” On some days, park managers measuring the sound level can’t get a decibel reading at all, and what they end up measuring, in fact, is not the hushed soundscape of the crater, but the sound of metal fatigue in the recording equipment itself.

Part of why the crater is so quiet is because it’s been cordoned off, protected from the works of man. Haleakala was originally set aside in 1916 as part of Hawaii National Park, which also included Kilauea and Mauna Loa on the Big Island; in 1961 they split into Haleakala and Hawai‘i Volcanoes national parks. Of course, national park status alone isn’t enough to make a place quiet, as any visit to Yellowstone will prove. But here an unusual mix of other factors comes into play: Huge sections of Haleakala are almost devoid of life, so there are no leaves or animals to make sound; the bowl and the cinder cones offer shelter from the wind; even the altitude, which keeps the crater cooler than the lowlands, slows and changes the way sound moves across the landscape.

Liz points to a spot on the map near the Halali‘i cone but doesn’t want to get more specific. Nor do I ask: Quiet is a matter of discovery, something to home in on.