Inactive volcanoes are not considered completely extinct because they erupted in the last 10, 000 years. Hualalai, the third of Hawaii's active shield volcanoes, is located northwest and west of its giant neighbors Mauna Loa and Mauna Kea.
Hualalai
volcano last erupted between 1800-1801, when it produced lava flows from 5 fissure vents that reached the sea and buried Hawaiian villages. The Hualalai began to erupt about 800,000 years ago and broke the surface of the sea about 300,000 years ago.The volcano has 3 rift zones, the most prominent being the northwest rift, which is about 40 km long and continues in the sea to a depth of 3000 m. Mauna Kea volcano is one of the most interesting volcanoes on the island of Hawaii. Considered inactive (a sleeping giant), Mauna Kea last erupted about 3,500 years ago. Mauna Kea is the tallest mountain in the world when measured from its base on the seabed.
Just below the summit, the mysterious Lake Waiau is one of the tallest lakes in the United States. Lava flows represent by far the greatest danger in a possible future Hualalai eruption, because although explosive pyroclastic eruptions have occurred during the Holocene epoch (the last 10,000 years), they are relatively rare and cover only limited parts of the volcano. Looking south from Kohala Volcano 40 miles (64 km) north of Kona, the outskirts of Waimea (Kamuela) are visible in the foreground. Hualalai, Mount Hualalai, Hualalai Mountain or Hualalai Volcano: it's just one name, Hualalai.
Lava flows from Hualalai and Kohala volcanoes (along with coral deposits) have buried most of Mahukona volcano. For additional information on Hualalai Volcano, visit the USGS Hawaiian Volcano Observatory (Hualalai) page. However, in 1929 an intense earthquake swarm hit Hualalai for a period of one month, which has been interpreted as due to an intrusion of magma near the surface, without a superficial eruption. Although 200 years have passed since the last Hualalai eruption, it is almost certain that it will erupt again.
Due to this and the fact that more than 200 years have passed since its last eruption, Hualalai volcano is considered a potentially dangerous volcano on the island of Hawaii that is delayed for an eruption. During this period, no microearthquake swarms or harmonic tremors (both indicative of magma migration) have been recorded, although Hualalai experiences several magnitude 4 earthquakes each year. Of course, things can change at any time with an active volcano in Hawaii, depending on the whims of Pelé, the goddess of fire and Hawaiian volcanoes. Hawaiian volcanoes are known as shield volcanoes because of the characteristic shape they take when lava flows out.
All of the volcanoes (both active and inactive) in this long chain were formed due to the Hawaiian hot spot, a stationary plume of superheated material deep in the earth. This also presents a clear danger to the surrounding communities; for example, in the event of an eruption similar to that of 1801, Kailua-Kona, which is 15 miles (24 km) from the summit of the volcano, could be completely covered in a matter of hours.
