tropical; on the slopes, environments range from tropical rainforest (more than 200 inches or 5,100 millimeters per year), through a temperate climate, to alpine conditions with a cold, dry climate. The rainy climate impacts soil development, which largely determines ground permeability, affecting the distribution of streams and wetlands.
The Hawaiian islands were formed by volcanic activity initiated at an undersea magma source called the Hawaii hotspot. The process is continuing to build islands; the tectonic plate beneath much of the Pacific Ocean continually moves northwest and the hot spot remains stationary, slowly creating new volcanoes. Because of the hotspot’s location, all currently active land volcanoes are located on the southern half of Hawaii Island. The newest volcano, Lōʻihi Seamount, is located south of the coast of Hawaii Island.
The last volcanic eruption outside Hawaii Island occurred at Haleakalā on Maui before the late 18th century, possibly hundreds of years earlier. In 1790, Kīlauea exploded; it was the deadliest eruption known to have occurred in the modern era in what is now the United States. Up to 5,405 warriors and their families marching on Kīlauea were killed by the eruption. Volcanic activity and subsequent erosion have created impressive geological features. Hawaii Island has the second-highest point among the world’s islands.
On the flanks of the volcanoes, slope instability has generated damaging earthquakes and related tsunamis, particularly in 1868 and 1975. Steep cliffs have been created by catastrophic debris avalanches on the submerged flanks of ocean island volcanoes.
The Kīlauea erupted in May 2018, opening 22 fissure vents on its East Rift Zone. The Leilani Estates and Lanipuna Gardens are situated within this territory. The destruction affected at least 36 buildings and this coupled with the lava flows and the Sulfur dioxide fumes, necessitated the evacuation of more than 2,000 local inhabitants from the neighborhoods.
Flora and fauna
See also: Endemism in the Hawaiian Islands and List of invasive plant species in Hawaii
Corvus hawaiiensis, the endemic Hawaiian crow (ʻalalā), is extinct in the wild.
Because the islands of Hawaii are distant from other land habitats, life is thought to have arrived there by wind, waves (i.e. by ocean currents) and wings (i.e. birds, insects, and any seeds they may have carried on their feathers). This isolation, in combination with the diverse environment (including extreme altitudes, tropical climates, and arid shorelines), allowed for the evolution of new endemic flora and fauna. Hawaii has more endangered species and has lost a higher percentage of its endemic species than any other U.S. state. One endemic plant, Brighamia, now requires hand-pollination because its natural pollinator is presumed to be extinct. The two species of Brighamia—B. rockii and B. insignis—are represented in the wild by around 120 individual plants. To ensure these plants set seed, biologists rappel down 3,000-foot (910 m) cliffs to brush pollen onto their stigmas.
The extant main islands of the archipelago have been above the surface of the ocean for fewer than 10 million years; a fraction of the time biological colonization and evolution have occurred there. The islands are well known for the environmental diversity that occurs on high mountains within a trade winds field. On a single island, the climate around the coasts can range from dry tropical (less than 20 inches or 510 millimeters annual rainfall) to wet tropical; on the slopes, environments range from tropical rainforest (more than 200 inches or 5,100 millimeters per year), through a temperate climate, to alpine conditions with a cold, dry climate. The rainy climate impacts soil development, which largely determines ground permeability, affecting the