Hawaiian hotspot in the context of "Mantle plume"

The Hawaiian Islands (Hawaiian: Mokupuni Hawaiʻi) are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some 1,500 miles (2,400 kilometers) from the island of Hawaiʻi in the south to northernmost Kure Atoll. Formerly called the Sandwich Islands by Europeans, the present name for the archipelago is derived from the name of its largest island, Hawaiʻi.

The archipelago sits on the Pacific Plate. The islands are exposed peaks of a great undersea mountain range known as the Hawaiian–Emperor seamount chain, formed by volcanic activity over the Hawaiian hotspot. The islands are about 1,860 miles (3,000 km) from the nearest continent and are part of the Polynesia subregion of Oceania.

A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.

On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and because most of Earth's plate boundaries are underwater, most volcanoes are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes resulting from divergent tectonic activity are usually non-explosive whereas those resulting from convergent tectonic activity cause violent eruptions. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift, the Wells Gray-Clearwater volcanic field, and the Rio Grande rift in North America. Volcanism away from plate boundaries most likely arises from upwelling diapirs from the core–mantle boundary called mantle plumes, 3,000 kilometres (1,900 mi) deep within Earth. This results in hotspot volcanism or intraplate volcanism, in which the plume may cause thinning of the crust and result in a volcanic island chain due to the continuous movement of the tectonic plate, of which the Hawaiian hotspot is an example. Volcanoes are usually not created at transform tectonic boundaries where two tectonic plates slide past one another.

Kīlauea (US: /ˌkɪləˈweɪə/ KIL-ə-WAY-ə, Hawaiian: [kiːlɐwˈwɛjə]) is an active shield volcano in the Hawaiian Islands. It is located along the southeastern shore of Hawaii Island. The volcano is between 210,000 and 280,000 years old and grew above sea level about 100,000 years ago. Since the islands were settled, it has been the most active of the five volcanoes that together form the island and among the most active volcanoes on Earth. The most recent eruption began in December 2024, with episodic lava fountains and flows continuing into 2025.

Kīlauea is the second-youngest product of the Hawaiian hotspot and the current eruptive center of the Hawaiian–Emperor seamount chain. Because it lacks topographic prominence and its activities historically coincided with those of Mauna Loa, Kīlauea was once thought to be a satellite of its much larger neighbor. Kīlauea has a large, fairly recently formed caldera at its summit and two active rift zones, one extending 125 km (78 mi) east and the other 35 km (22 mi) west. An active fault of unknown depth moves vertically an average of 2 to 20 mm (0.1 to 0.8 in) per year.