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Dating earthquakes with high-precision thorium-230 ages of very young corals

Edwards, R. Lawrence and Taylor, F. W. and Wasserburg, G. J. (1988) Dating earthquakes with high-precision thorium-230 ages of very young corals. Earth and Planetary Science Letters, 90 (4). pp. 371-381. ISSN 0012-821X. http://resolver.caltech.edu/CaltechAUTHORS:20131025-154223555

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Abstract

Mass spectrometric techniques have recently yielded significant increases in precision and sensitivity over previous methods for measuring ^(230)Th abundance in corals. To assess the accuracy of ^(230)Th ages, three corals from Vanuatu, whose ages were known from counting annual growth bands, were analyzed. For each sample, the date of growth determined by ^(230)Th analysis (A.D.1969 ± 3, 1932 ± 5,and1806 ± 5; 2σ uncertainties based on analytical error) was indistinguishable from the date determined by counting bands (A.D. 1971–1973, 1935–1937, and 1804–1810), indicating that the ^(230)Th dates are accurate. ^(230)Th dates were also determined for two adjacent emerged heads from Santo Is., Vanuatu, which were thought to have died when they were raised above sea level during coseismic uplift. The dates (A.D.1864 ± 4, 1866 ± 4) were the same, indicating that the heads died at the same time and consistent with the idea that they were killed by coseismic emergence around A.D. 1865. The difference between this date and the date of the only major historically documented earthquake that caused uplift (A.D. 1973,M_s = 7.5), suggests a seismic recurrence interval of108 ± 4y for Santo. Analogous emerged corals from Malekula Is., Vanuatu yielded ^(230)Th dates that were similar to each other (A.D.1729 ± 3, 1718 ± 5) and are inferred to have died during coseismic emergence around A.D. 1729. In conjunction with the date of the only large historically documented earthquake that caused uplift (A.D. 1965,M_s = 7.5), the recurrence interval for Malekula is236 ± 3y. If similar emerged corals can be found, this appraoch may be extended back in time and to other localities because it appears that such features can now be dated both accurately and precisely.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/0012-821X(88)90136-7DOIArticle
http://www.sciencedirect.com/science/article/pii/0012821X88901367PublisherArticle
Additional Information:© 1988 Elsevier Science Publishers B.V. Received June 14, 1988; revised version received September 8. 1988. We thank J.H. Chen and D.A. Papanastassiou for advice and support, and K.E. Sieh for stimulating discussion. This document was written while the senior author was at and supported by the Department of Geology and Geophysics at the University of Minnesota. Constructive comments from two anonymous reviewers were beneficial. We thank the crews of the vessels "V au ban" and "Lopevi". The assistance of L. Gilpin, D. Sogari, P. Vuti, J.-L. Laurent, and the people of the villages of Brenwe, Levi amp, and W ounpouku are gratefully acknowledged. J.-L. Saos, J. Bonnemaison, R. Campillo, J. Recy, and C. Reichenfeld are thanked for support with fieldwork. The age determinations were done in the Lunatic Asylum at Caltech, supported by NASA Grant NAG 9-43. The Government of Vanuatu and ORSTOM are thanked for field support. Fieldwork was funded by NSF grant EAR 79-19912 to F.W.T. This is contribution number 1113(2) from the Department of Geology and Geophysics, School of Earth Sciences, University of Minnesota; 751 from the Institute for Geophysics, University of Texas at Austin; and 4632 (623) from the Division of Geological and Planetary Sciences, California Institute of Technology.
Funders:
Funding AgencyGrant Number
NASANAG 9-43
NSFEAR 79-19912
Other Numbering System:
Other Numbering System NameOther Numbering System ID
University of Minnesota Department of Geology and Geophysics, School of Earth Sciences1113
University of Texas at Austin Institute for Geophysics751
Caltech Division of Geological and Planetary Sciences4632
Lunatic Asylum Lab623
Record Number:CaltechAUTHORS:20131025-154223555
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20131025-154223555
Official Citation:R.Lawrence Edwards, F.W. Taylor, G.J. Wasserburg, Dating earthquakes with high-precision thorium-230 ages of very young corals, Earth and Planetary Science Letters, Volume 90, Issue 4, 25 November 1988, Pages 371-381, ISSN 0012-821X, http://dx.doi.org/10.1016/0012-821X(88)90136-7. (http://www.sciencedirect.com/science/article/pii/0012821X88901367)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42080
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:28 Oct 2013 16:04
Last Modified:28 Oct 2013 17:37

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