Modern diatom assemblages from Chilean tidal marshes and their application for quantifying deformation during past great earthquakes

Emma P. Hocking*, Ed Garrett, Marco Cisternas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Tidal marsh sediments from south-central Chile provide evidence for multiple great earthquakes. Diatom transfer functions, statistical models of the relationship between species preserved in the sediment and elevation, provide quantitative estimates of coseismic vertical land-level change associated with individual earthquakes. However, in south-central Chile, our ability to quantify land-level change is currently limited by a lack of understanding of the environmental variables controlling the distribution of diatoms, an essential prerequisite for converting variations in fossil diatom assemblages into quantitative estimates of past elevation changes. We present a new modern diatom dataset for the region and explore the implications of the scale of the dataset used in transfer function models on the reconstructions of land-level change. Modern training sets containing samples from a regional scale are superior to sub-regional and local-scale training sets, providing closer estimates for known deformation during the great 1960 Chilean earthquake, a higher proportion of good modern analogues and uncertainty terms up to 42% smaller than previously published reconstructions.

Original languageEnglish
Pages (from-to)396-415
Number of pages20
JournalJournal of Quaternary Science
Volume32
Issue number3
DOIs
Publication statusPublished - 1 Apr 2017

Bibliographical note

© 2017 The Authors.

Keywords

  • coseismic land-level change
  • modern training sets
  • palaeoseismology
  • relative sea-level change
  • transfer functions

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