Haʻakulamanu (Sulphur Banks)

Haʻakulamanu (the Sulphur Banks) is a volcanic thermal field on Kīlauea where gases and groundwater steam seep through fissures, leaving yellow sulfur and red-brown altered ground. Keep it in your day if you want to see volcanic chemistry at trail level; it's an unusual, close-up stop, not a big crater panorama. The odor is part of the visit, and it can be strong. NPS advises people with heart or respiratory conditions, including asthma, and pregnant women, infants, and young children to avoid the walk.

The established trail is an easy 1.2-mile round trip, starting from Kūkamāhuākea (Steam Vents) parking. Expect paved path and boardwalk sections with interpretive signs as the trail takes you from the starting area to the colorful deposits. The sulfur banks are reached on the walk, so this takes more than a pullout pause.

At nearby Wahinekapu, the Steam Vents, heated groundwater mainly escapes as steam. Haʻakulamanu's deeper fractures also bring volcanic gases to the surface. Sulfur dioxide and hydrogen sulfide react to form pure yellow sulfur; acid breaks down lava into clay, and iron oxide stains it red and brown. That chemistry is why the banks look different from the neighboring steam vents.

Visitors were already calling it the Sulphur Banks in the early 1800s. The yellow sulfur is known as kūkaepele, translated as “the waste of Pele.”

Two test holes drilled here in 1922 showed 205°F (96°C) at depths down to 50 feet (15 m), the deepest point they reached. That steady heat helps explain why the gas-and-steam system alters the exposed rock.

Once you reach the banks, look for a frame that holds the vapor above the pale yellow and red-brown ground; the contrast is what makes these close views distinctive. You'll see it from the trail rather than directly beside the parking area.