The Massive 2005 Dabbahu (Afar, Ethiopia) rifting event: Capturing the birth of oceanic lithosphere with InSAR. Abstract

abstract

  • Between 20 September and 8 October 2005, 162 earthquakes (m_b >4) occurred within the ~60 km long Dabbahu magmatic segment of the Afar rift, a nascent seafloor spreading centre in stretched continental lithosphere (Barberi and Varet, 1970; Hayward and Ebinger, 1996). Early InSAR results suggest this was the largest rifting event to have occurred in the era of satellite geodesy; simple elastic modelling shows that the entire magmatic segment opened by up to 8 m, yet seismic deformation can account for less than 10% of the observed deformation. First-order models of the interferograms indicate magma was injected along a dyke between depths of 2 and 8 km, corresponding to a total intrusion volume of ~2.5 km^3. Approximately 20% of the magma was sourced from shallow chambers beneath Dabbahu and Gabho stratovolcanoes at the northern end of the segment, where an explosive fissural eruption occurred. Although comparable in magnitude to the 1975-1984 Krafla (Iceland) events (Tryggvasson. 1984), seismic data suggest that most of the Dabbahu dyke intrusion occurred in

authors

publication date

  • 2006

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