The Rise of Sea Level in Contemporary Times at Honaunau, Kona, Hawaii

Abstract

Bait cups, net-tanning tubs, and playing boards for the checker-like game of konani, which were hollowed out by the ancient Hawaiians on the surface of pahoehoe lava flows a short distance above sea level at the City of Refuge, Honaunau, Hawaii, are now submerged and unusable for their original purpose. Increased depth of water over the traditional land route used in approaching the place of refuge, comparisons of old and new photographs, and increasing storm damage to structures, also indicate a relative sinking of the shore, at a rate of about 1 ft per century. The sinking is endangering some of the structures, and imposes a special problem in the preservation of the area. Other evidence indicates sinking of other parts of the island of Hawaii, but by less definite amounts. The rate of change of relative level of land and sea at Honaunau is much greater than that of world wide change of sea level, and must be the result of actual sinking of the island. The logical explanation lies in isostatic adjustment resulting from loading of the earth's crust by the great added mass of the volcanoes. The southern part of the island of Hawaii appears to be sinking isostatically at a rate of about 8 or 9 inches a century.