Large cliffs develop on the Big Island of Hawai'i primarily as a result of gigantic debris avalanches that carry a large portion of the island into the deep ocean, leaving behind cliffs and a scalloped coastline. The Alika debris avalanche did this exact thing about 120,000 years ago, with a runout of about 60 miles across the ocean floor. The slide produced a huge tsunami that dumped chunks of coral more than 1,000 feet above sea level on Lana'i (most tsunamis generated by earthquakes rarely exceed 100 feet in height). If such an event were to happen today, the effects would be unthinkably horrific. Luckily, they are rare, tens of thousands of years apart. There would presumably be many signs of an impending collapse (one would hope, anyway).
|Hikiau Heiau at Kealakekua Bay|
The park at Kealakekua Bay preserves Hikiau Heiau (above), a huge structure dedicated to the war god Ku, and Lono, the god associated with fertility of the land. It has been damaged by a number of tsunamis, but has been repaired and is still sometimes utilized for ceremonies.
The cliff at Kealakekua Bay is of special importance to native Hawaiians. It's called Pali Kapu O Keoua ("the forbidden cliff of Keoua"), and the various holes and caves in the cliff contain the bones of royalty. Such bones are said to possess great power (mana), and so great effort was invested in keeping their location hidden (I seem to remember reading that a trusted servant would dangle from a rope on such cliffs, and when he had hidden the bones, the rope would be cut and the servant would plunge to his death; an honor, I guess, but not a great job benefit).
The effect of European contact cannot be overstated. While the arrival of western technology allowed King Kamehameha I to gain control of the entire island chain, forming the nation of Hawai'i, disease decimated the Hawaiian people (from as many as 1,000,000 to maybe 30,000). Just over a century later the island was taken over by corporate interests, before becoming a territory of the United States. Although the Polynesians had caused the extinction of native species through the introduction of invasive animals and plants, the process was greatly accelerated with the arrival of the Europeans.
|Pu'uhonua o Honaunau|
|Heiau in the sanctuary at Pu'uhonua o Honaunau|
|Fishpond at Pu'uhonua o Honaunau|
Pu'uhonua o Honaunau and Kealakekua Bay exude a sense of peace today, but they mask a turbulent past, both geological, and anthropological. If you are ever on the Big Island, they are two very interesting stops.