Moho map of South America from receiver functions and surface waves

Simon Lloyd*, Suzan van der Lee, George Sand França, Marcelo Assumpção, Mei Feng

*Corresponding author for this work

Research output: Contribution to journalArticle

61 Scopus citations

Abstract

We estimate crustal structure and thickness of South America north of roughly 40S. To this end, we analyzed receiver functions from 20 relatively new temporary broadband seismic stations deployed across eastern Brazil. In the analysis we include teleseismic and some regional events, particularly for stations that recorded few suitable earthquakes. We first estimate crustal thickness and average Poisson's ratio using two different stacking methods. We then combine the new crustal constraints with results from previous receiver function studies. To interpolate the crustal thickness between the station locations, we jointly invert these Moho point constraints, Rayleigh wave group velocities, and regional S and Rayleigh waveforms for a continuous map of Moho depth. The new tomographic Moho map suggests that Moho depth and Moho relief vary slightly with age within the Precambrian crust. Whether or not a positive correlation between crustal thickness and geologic age is derived from the pre-interpolation point constraints depends strongly on the selected subset of receiver functions. This implies that using only pre-interpolation point constraints (receiver functions) inadequately samples the spatial variation in geologic age. The new Moho map also reveals an anomalously deep Moho beneath the oldest core of the Amazonian Craton.

Original languageEnglish (US)
Article numberB11315
JournalJournal of Geophysical Research: Solid Earth
Volume115
Issue number11
DOIs
StatePublished - Nov 1 2010

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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