Mauka · Hualālai
Hualālai still sleeps.
Above Kaʻūpūlehu rises Hualālai, the third-most-active of Hawaiʻi Island's volcanoes. Its last eruption — in 1800–1801 — sent two lava flows toward the sea. The mountain has been quiet since, but USGS still classes it as active.
Mid · the flow
The 1801 flow buried a village.
Hawaiian oral history records that the 1801 Kaʻūpūlehu flow advanced toward the village over weeks. Kamehameha himself is said to have offered a lock of his hair to Pele to turn the flow aside. The flow eventually stopped — but the village was lost.
Walking the trail here means crossing a fresh-on-geological-time ʻaʻā field. The cinder cone source is visible mauka; the ocean accepts the flow's terminus makai.
Open this section in the map (lava layer on) →Coast · the lava shore
Where lava meets the Pacific.
The 1801 flow reached the coast in two lobes. The terminus is now an anchialine pool complex and a rocky shore — exactly the geological raw material out of which a new fishpond, in another century, might be built.
Reef · young coral
Young coral on young lava.
Coral colonies establish on submerged lava on a timescale of decades. The reef offshore of Kaʻūpūlehu is, by geological standards, an infant — recovery and resettlement still actively underway.
Ocean · kai
The deep channel is right here.
Within a mile offshore the seafloor drops past 600 m. Humpback singers favor this drop-off: their song carries clean into the deep canyon.