Vacation Rental in Princeville Kauai
and Kauai Travel Guide
Geology of Kauai and Hawaii
The Hawaiian chain of volcanic peaks–consisting of 132 islands, islets, reefs and shoals–stretches 1,523 miles northwest to southeast across the center of the Pacific Ocean. There is more to the Hawaiian Islands than the land you see. If the ocean was drained of its water, this chain would appear as a lofty mountain range. Kauai, fourth in size, lies at the northwest end of the eight main islands.
Each volcanic cone is built of dark, iron-
Like most of the world’s volcanoes, the Hawaiian cones spawned from a zone of weakness
in the earth's crust. Weaknesses occur where giant, slow-
The stationary hot spot in the earth’s mantle that caused Kauai's birth, and later spawned the island of Oahu and the island cluster of Maui, Molokai, Lanai and Kaho‘olawe, now remains beneath the island of Hawaii. For 70 million years, a plate of the earth’s crust has been moving over that hot spot. Again and again, molten rock has risen from the hot spot to build volcanic islands, and in the seemingly endless procession of geologic time they have drifted away, riding aboard the plate. The oldest volcanoes created by this event are the submerged Emperor Seamounts, which now lie north of the island of Midway. The youngest volcano is a burgeoning seamount named Lo‘ihi, 20 miles southeast of the island of Hawaii. This embryonic island must grow another 3,180 feet before it emerges from the ocean—60,000 years from now.
The volcanoes of the Hawaiian chain are rounded, dome-
Around the rim of the Pacific Ocean more viscous lava flows have produced the classic upswept form of a composite volcano. The lava does not flow far before it solidifies, building higher and higher around its vent. Famous composite volcanoes are Fuji in Japan and Rainier, Hood, Shasta and St. Helens in the United States.
Hawaiian volcanoes generally erupt along cracks in the cone’s flanks. Movement within
the earth’s crust tears open a series of fissures, forming a rift zone. Pressing
through the cracks, magma fountains onto the land as lava. When an eruption is over,
the lava remaining in the fissure hardens into a wall-
Wai‘ale‘ale, the volcano that formed Kauai, had two principal periods of eruptive
activity. Between five and six million years ago, lava flows broke the ocean's surface.
Thin flows of lava, each from 5 to 15 feet thick, piled atop each other to eventually
building a broad, smooth, dome-
Fields of rubble in the ocean floor indicate that massive pieces of the island broke
off and slid into the ocean. A slide split the summit of Wai‘ale‘ale along a north-
Another catastrophic slide later broke a large portion off of the north flank of Wai‘ale‘ale. The towering sea cliff left behind eroded into the Na Pali coastline. Slides of such magnitude must surely have generated big tsunamis.
Eruptions of lava continued after the slides, building a new volcanic shield in the
dropped eastern portion of the island. A caldera formed in the new shield that eventually
eroded into the Līhu‘e depression, a broad basin five miles northwest of Līhu‘e.
Building and rebuilding of the shield that formed Kauai continued until 4.3 million
years ago. Running water shaped the gentle volcanic slopes into a landscape of jagged
ridges and deep valleys. After a time of volcanic quiescence, eruptions began again.
This period of renewed volcanism started 3.65 million years ago and lasted until
half a million years ago. The lava, cinder cones and ash beds produced from these
more modern eruptions are identified as the Koloa volcanic series. The largest volcanic
vent of the newer series is Kilohana, the 1,133-
Kauai, which appeared late in geological history, is doomed to extinction, but on