Hiking Kohala: Visually captivating View of ALL Big Island Volcanoes! Hualālai,Mauna Loa/Kea,Kīlauea

Hiking Kohala: Visually captivating View of ALL Big Island Volcanoes! Hualālai,Mauna Loa/Kea,Kīlauea

USGS
Kohala Volcano is extinct; it consists of shield lavas, including the oldest lavas from the island of Hawaii, dated at about 460,000 years old, and postshield-stage lavas as young as 60,000 years old. Its northwest rift zone extends through an elongate summit depression, apparently an extensional basin at the headwall of the Pololu landslide that moved towards the northeast. Waipi'o and Pololu valleys have formed along faults that bounded this landslide, which occurred before eruption of postshield-stage lavas began about 260,000 years ago. The thick ash cover on Kohala Volcano is derived mostly from Mauna Kea, although some is probably of local origin.

The Kohala volcano is distinguished by its extinct status and significant age, which has led to unique geological and ecological features. Unlike the younger, symmetrical volcanoes of the island, Kohala is heavily eroded and shaped by ancient mega-landslides and massive tsunamis.

Geology and landscape
Massive debris avalanche: Between 250,000 and 300,000 years ago, a catastrophic landslide sheared off the volcano's northeastern flank. This event created the spectacular, sheer cliffs of the windward coast and the deep, verdant valleys, such as Waipiʻo and Pololū.
Foot-like shape: The large landslide is likely responsible for Kohala's distinctive, foot-like shape, which sets it apart from the more classic dome profiles of other Hawaiian shield volcanoes.

Evidence of mega-tsunami: Geological studies have found marine fossils deposited high up on the volcano's flank, far above sea level. This is evidence of a mega-tsunami that occurred approximately 120,000 years ago, likely triggered by a landslide from the neighboring Mauna Loa volcano.

Rich phosphorus soil: Unlike other Hawaiian volcanoes, Kohala's later lava flows are rich in phosphorus. This has created areas with highly fertile soil, which ancient Hawaiians identified and used for extensive dryland agriculture.

Extinct status: As the oldest of the five subaerial volcanoes on the Big Island, Kohala is extinct, with its last eruption occurring about 120,000 years ago. Its low risk for volcanic hazards is a result of it being in the late stage of its volcanic life cycle.

Ecosystem and climate
Vast watershed: Kohala's summit forests and cloud forests act as a natural sponge, absorbing large amounts of the 150 inches of rain the area receives annually. This recharges the island's groundwater and feeds the streams that run through the deep valleys.

Drastic microclimates: The difference in climate between Kohala's wet, windward side and its dry, leeward side is dramatic. The high rainfall on the northeast side sustains lush forests, while the southwest side is much drier.
Isolated ecosystem: The geographical isolation of the Kohala ecosystem has led to the evolution of many unique endemic species of plants and animals, some of which are not found anywhere else.