HR: 0830h
AN: G21B-0262    [PDF]
TI: Diatom-based elevation transfer function along the Pacific coast of eastern Hokkadio, northern Japan - an aid in paleo-seismic study along the coasts near Kurile subduction zone
AU: * Horton, B P
EM: b.p.horton@durham.ac.uk
AF: University of Durham, Department of Geography University of Durham, Durham, DH1 3LE United Kingdom
AU: Sawai, Y
EM: yuki.sawai@aist.go.jp
AF: National Institute of Advanced Industrial Science and Technology, Active Fault Research Center, GSJ/AIST National Institute of Advanced Industrial Science and Technology Site C7 1-1-1 Higashi Japan, Tsukuba, 305-8567 Japan AB: This paper provides a training data set for diatom-based elevation transfer functions, which are applicable to paleoseismic studies at southwestern Kurile subduction zones, northern Japan. Contemporary diatom samples were collected from four transects at Akkeshi and Onnetoh salt marshes along the Pacific coast of eastern Hokkaido. The relationships between diatom species and environmental variables were elucidated by canonical correspondence analysis (CCA) and partial CCAs. Partial CCAs associated with Monte Carlo permutation tests show that elevation accounts for a significant portion of the total variance in the diatom data. Therefore, statistically significant transfer functions quantifying the relationship between contemporary diatom assemblages and elevation can be developed. Diatom-based transfer functions (DBTFs) were developed using weighted averaging and partial least squares (WA-PLS) and applied to fossil diatom assemblages from Onnetoh estuary. The reconstructed curve of elevations contains at least three obvious emergence and DBTFs evaluated the magnitude of the three emergences as approximately 80 cm. The results are consistent with paleoecological data produced by previous studies. If these cycles represent subsidence during an interseismic period and uplift associated with interplate earthquake along the Kurile subduction zones, DBTFs at salt marshes of eastern Hokkaido can contribute to reconstruction of the recurrence intervals and the magnitudes of earthquakes.
DE: 1200 GEODESY AND GRAVITY
DE: 3030 Micropaleontology
DE: 4235 Estuarine processes
DE: 4556 Sea level variations
SC: Geodesy [G]
MN: 2003 Fall Meeting