GEOLOGY OF HAWAII
Formation of the Hawaiian Island Chain
The Hawaiian islands were created over millions of years by the movement of the the Pacific tectonic plate over a "hot spot"
in the earth's mantle. Periodic eruptions from the sea floor formed an island chain of more than 20 islands and atolls stretching
along thousands of miles. The hot spot is currently off the south east coast of the Big Island. As the islands move northwest,
they become inactive and are eroded away by wind, rain and ocean waves.
Kauai is the oldest of the main Hawaiian Islands, formed 5 million years ago, and is considered extinct. Oahu and Maui are next in the
chain. The volcanos on Oahu including famous Diamondhead are extinct but Haleakala on Maui erupted about 10000 years ago and may not be extinct.
The youngest and most active in the chain is our Big Island home where Kilauea is still very active. Loihi, 20 miles to the southeast and under
about 3000 feet of water, will be the next Hawaiian island to form.
Hawaiian volcanoes are referred to as "shield volcanoes," because they resemble the shape of a warrior's shield.
Molten lava rises from a hot spot in the Earth's crust, erupting through various vents and rifts on the surface,
and proceeds to move down the gentle slopes toward the ocean, building up layer upon layer over millions of years.
Big Island Volcanoes
The Big Island of Hawaii was formed from five volcanoes. Each has its own unique characteristics that create the natural beauty of each part of the island.
Kohala is the northwestmost and oldest volcano of the Big Island and last erupted about 60,000 years ago. Because of its age, the Kohala volcano is the most eroded
and has many steep valleys plunging all the way to the ocean. The famous Waipaio Valley is here as is the town of Hawi. There are a gerat many
luxury resorts along the spectacular Kohala Coast on the west side. Its eastern side is characterized by deep valleys, spectacular waterfalls, and dramatic sea cliffs
created by an ancient landslide that extended 50 miles out to sea. The summit elevation is 1,670 meters, or 5,480 feet.
Mauna Kea is the tallest mountain in Hawaii at 4,205 meters, or 13,796 feet, and
measured from its base off the ocean floor is the tallest mountain in the world. It last erupted around 4,500 years ago,
and the oldest exposed lava is about 250,000 years old. A climb to the summit passes through several climatic zones and biomes.
Mauna Kea is also the home of one variety of the rare silversword plant. It has several cinder cones, two glacial valleys
an alpine glacier lake near the summit, which is often covered with snow. It is also home to the greatest astronomical complex on earth.
Our vacation rental condo is on the slopes of Hualalai which rises to a height of 2,521 meters (8,271 feet) and last erupted in 1801, creating
the lava at the Kona International Airport and at Kekaha Kai State Park. The oldest exposed lava is from the Pu'uwa'awa'a and Pu'uanahula
eruptions which occurred 120,000 years ago. Hualalai is home to a native forest, hostile dry lowlands, pit craters, eruptive vents,
lava tubes, stark cinder highlands, a collection of archeological sites, and thousands of acres of remote backcountry.
Mauna Loa is the world's largest mountain and is one of the most active volcanoes on earth, last erupting in 1984.
It constitutes more than half of the surface area of the Big Island and rises 4,136 meters, 13,570 above sea level.
As the volcano has built itself off the ocean floor, it has pushed down a mirror image into the earth's crust.
This depression extends 26,000 feet from the ocean floor. From this deepest point to its summit, Mauna Loa rises 56,000 feet.
Kilauea is the youngest on the island, and is one of the world's most active volcanoes, with a large summit caldera.
Over ninety percent of its surface area is covered with lava less than 1500 years old. Its summit rises to only 1,248 meters, or 4,093 feet.
It is still growing and may completely cover its giant neighbor Mauna Loa in the future. It has been erupting continuously for more than two decades.
One of its vents, Mauna Ulu, last erupted nearly continuously between 1969 and 1974, filling the `Alo`i and `Alae craters along the old Chain of Craters Road.
A hike to the top provides a spectacular view of expansive lava flows.
The Big Island of Hawaii was formed from five volcanoes. Hawaiian lava is made primarily of basalt, a rock with low silica
content, which allows it to flow smoothly and non-explosively, creating low-sloping shield volcanoes. Common minerals in basalt
include the beautiful green mineral olivine, and pyroxene and plagioclase. Look for small green crystals of Hawaiian diamond within the hardened lava.