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 only active volcanism in the last 200 years has been on the southeastern island, Hawaiʻi, and on the submerged but growing volcano to the extreme southeast, Kamaʻehuakanaloa (formerly Loʻihi).

The combination of erosional forces, which cause slumping and landslides, with the pressure exerted by rising magma put a great amount of stress on the volcanic flanks.

This type of seismicity is unique because the forces driving the system are not always consistent over time, since rates of volcanic activity fluctuate.

Flank earthquakes typically occur at depths ranging from 5 to 20 km, increasing the hazard to local infrastructure and communities.

Most of the early earthquake monitoring took place in Hilo, by missionaries Titus Coan and Sarah J. Lyman and her family.

Several major roadways became impassable from rock slides, and effects were felt as far away as Honolulu, Oahu, nearly 150 miles (240 km) from the epicenter.

The island of Molokaʻi had a catastrophic collapse or debris avalanche over a million years ago; this underwater landslide likely caused tsunamis.

It was relatively minor, but local emergency management officials utilized the latest technology and ordered evacuations in preparation for a possible major event.

The Kamaʻehuakanaloa Seamount is an active submarine volcano that is expected to become the newest Hawaiian island when it rises above the ocean's surface in 10,000–100,000 years.

Aided by European military technology, Kamehameha I conquered and unified the islands for the first time, establishing the Kingdom of Hawaii in 1795.

American immigration, led by Protestant missionaries, and Native Hawaiian emigration, mostly on whaling ships but also in high numbers as indentured servants and as forced labour, began almost immediately after Cook's arrival.

The government of Japan organized and gave special protection to its people, who comprised about 25 percent of the Hawaiian population by 1896.

Thereafter the Native Hawaiian population in Hawaii increased with every census, reaching 680,442 in 2020 (including people of mixed heritage).

In 1893 Queen Liliʻuokalani was illegally deposed and placed under house arrest by businessmen (who included members of the Dole family) with help from the U.S. Marines.

These included species such as rats and pigs, that have preyed on native birds and invertebrates that initially evolved in the absence of such predators.

[25] The arrival of the Europeans had a more significant impact, with the promotion of large-scale single-species export agriculture and livestock grazing.

This led to increased clearing of forests, and the development of towns, adding many more species to the list of extinct animals of the Hawaiian Islands.

[26] On June 15, 2006, President George W. Bush issued a public proclamation creating Papahānaumokuākea Marine National Monument under the Antiquities Act of 1906.

The Monument encompasses the northwestern Hawaiian Islands and surrounding waters, forming the largest[27] marine wildlife reserve in the world.

[34] The islands receive most rainfall from the trade winds on their north and east flanks (the windward side) as a result of orographic precipitation.

[34] In general, the lowlands of Hawaiian Islands receive most of their precipitation during the winter months (October to April).