Relationship between subsidence and volcanic load, Hawaii
- 250 Downloads
A computer analysis of tide-gage records in the northeast Pacific indicates that the active volcanic islands of eastern Hawaii are subsiding at a rate considerably faster than the eustatic rise of sea level. The rate of absolute subsidence increases progressively toward the center of current activity on the Island of Hawaii. Honolulu, Oahu, appears to be stable; Kahului, Maui, is subsiding at 1.7 mm per year; and Hilo, Hawaii, is subsiding at 4.8 mm per year. This subsidence is apparently related to downbowing of the crust throughout a zone 400 km in diameter by the weight of volcanic material added to the crust by active volcanoes, principally Mauna Loa and Kilauea on the Island of Hawaii. The Hawaiian Arch encircles the subsiding zone and may be uplifted by material moving down and outward from the zone of subsidence.
The annual volume of subsidence is about 270×106 m3, whereas the average annual volume of erupted basalt on the Island of Hawaii (based on historic records back to about 1820) is about 50×106 m3. The great excess of subsidence over volcanic addition cannot be reconciled by isostatic models, and is apparently the result of other processes operating in the volcano and its basement thet are poorly understood. Probably the more important of these processes are intrusions and submarine volcanism, both of which are providing additional unseen load on the volcanoes. Furthermore, the rate of eruption may be uplifted by material moving down and outward from the zone of subsidence may be overestimated due to localized downslope movement of the margins of the islands.
KeywordsTide Gage Mantle Material Annual Volume Kilauea Volcano Volcanic Pile
Unable to display preview. Download preview PDF.
- Apple, R. A. andMacdonald, G. A., 1966,The rise of sea level in contemporary times at Honaunau, Kona, Hawaii. Pacific Science, Vol. 20, n. 1, pp. 125–136.Google Scholar
- Bailey, D. K., 1964,Crustal warping a possible tectonic control of alkaline magmatism. Jour. Geoph. Research, Vol. 69, n. 6, pp. 1103–1111.Google Scholar
- Brigham, W. T., 1909,The volcanoes of Kilauea and Mauna Loa on the Island of Hawaii. Memoirs of the Bernice Pauahi Bishop Museum, Vol. 2, n. 4, 222 pp.Google Scholar
- Dietz, R. S. andMenard, H. W., 1953,Hawaiian Swell, Deep, and Arch, and subsidence of the Hawaiian Islands. Jour. Geol. Vol. 61, n. 2, pp. 99–113.Google Scholar
- Eaton, J. P., 1962,Crustal structure and volcanism in Hawaii. inThe Crust of the Pacific Basin, Am. Geoph. Union Mon. 6, pp. 13–29.Google Scholar
- Fiske, R. S. andKoyanagi, R. Y., 1968,The December 1965 eruption of Kilauea Volcano, Hawaii. U. S. Geol. Survey Professional Paper 607, 21 pp.Google Scholar
- Kinoshita, W. T., Drivoy, H. L., Mabey, D. R. andMacdonald, R. R., 1963,Gravity survey of the island of Hawaii. U. S. Geol. Survey Prof. Paper 475-C, pp. C114–C116.Google Scholar
- Macdonald, G. A. andHubbard, D. H., 1965,Volcanoes of the National Parks of Hawaii. Third Edition, Hawaii Natural History Assn., 52 pp.Google Scholar
- Menard, H. W., 1964,Marine geology of the Pacific. McGraw-Hill Book Co., New York, San Francisco, Toronto, London, 271 pp.Google Scholar
- Moore, J. G., 1964,Giant submarine landslides on the Hawaiian Ridge in Geological Survey Research 1964, U. S. Geol. Survey Prof. Paper 501-D, pp. D95–D98.Google Scholar
- ----- andPeck, D. L., 1965,Submarine lavas from the east rift zone of Mauna Kea, Hawaii. Geol. Soc. America Ann. Mtg., April 1965.Google Scholar
- Stearns, H. T., 1966,Geology of the State of Hawaii. Pacific Books, Palo Alto, Calif., 266 pp.Google Scholar
- ----- andClark, W. O., 1930,Geology and water resources of the Kau District, Hawaii. U. S. Geol. Survey Water-Supply Paper 616, 194 pp.Google Scholar
- ----- andMacdonald, G. A., 1946,Geology and groundwater resources of the Island of Hawaii, Hawaii Div. Hydrology, Bull. 9, 363 pp.Google Scholar
- Woollard, G. P., 1951,A gravity reconnaissance of the Island of Oahu. Am. Geoph. Union Trans., Vol. 32, n. 3, pp. 358–368.Google Scholar