Images of the East African Rift System by Global Adaptive-Resolution Surface-Wave Tomography

Félicie Korostelev, Yang Lu, Fabrizio Magrini, Lapo Boschi, Sylvie Leroy, William Vétel

Publications: Contribution to journalArticlePeer Reviewed

Abstract

In this study we map the entire East African Rift System (EARS) within a global surface-wave velocity model to better constrain the structure of the underlying mantle, as well as patterns that might be associated with its continuation in the Mozambique Channel. We use all publicly available seismograms from the African continent, amounting to 1296 stations and more than 30 years of recordings. From these data, we obtain dispersion curves using both ambient noise and teleseismic earthquakes. To our measurements, we add global counterparts and jointly invert them for phase-velocity maps. We exploit a linearized inversion based on the ray theory, with an adaptive parameterization that allows for maximizing the resolution of the final maps based on the density of data coverage. We thus image the main African cratons and also some of the Archean blocks within them. We highlight the discontinuous nature of magmatic activity along the EARS and also display low-velocity anomalies beneath the Comores Archipelago, Madagascar and Bassas da India volcanic islands and seamounts. This last low-velocity anomaly is in the direct continuation of the EARS and could unveil an important magmatic system in the Mozambique Channel.

Original languageEnglish
Article numbere2021JB023570
Number of pages18
JournalJournal of Geophysical Research - Solid Earth
Volume127
Issue number6
DOIs
Publication statusPublished - Jun 2022

Austrian Fields of Science 2012

  • 105122 Seismic

Keywords

  • 2-RECEIVER MEASUREMENTS
  • AMBIENT-NOISE
  • CONTINENTAL BREAKUP
  • CRUSTAL STRUCTURE BENEATH
  • East African Rift System
  • MALAWI RIFT
  • PHASE-VELOCITY
  • RUNGWE VOLCANIC PROVINCE
  • SEISMIC TOMOGRAPHY
  • UPPERMOST MANTLE
  • WESTERN BRANCH
  • surface-wave velocity model

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