International Journal of Earth Sciences

, Volume 100, Issue 6, pp 1375–1381 | Cite as

Recent plumbing system of the Krakatau volcano revealed by teleseismic earthquake distribution

Original Paper

Abstract

Spatial and temporal analysis of global seismological data 1964–2005 reveals a distinct teleseismic earthquake activity producing a columnar-like formation in the continental wedge between the Krakatau volcano at the surface and the subducting slab of the Indo-Australian plate. These earthquakes occur continuously in time, are in the body-wave (mb) magnitude range 4.5–5.3 and in the depth range 1–100 km. The Krakatau earthquake cluster is vertical and elongated in the azimuth N30°E, suggesting existence of a deep-rooted fault zone cutting the Sunda Strait in the SSW-NNE direction. Possible continuation of the fault zone in the SW direction was activated by an intensive 2002/2003 aftershock sequence, elongated in the azimuth of N55°E. Beneath the Krakatau earthquake cluster, an aseismic gap exists in the Wadati-Benioff zone of the subducting plate at the depths 100–120 km. We interpret this aseismic gap as a consequence of partial melting inhibiting stress concentration necessary to generate stronger earthquakes, whereas the numerous earthquakes observed in the overlying lithospheric wedge beneath the volcano probably reflect magma ascent in the recent plumbing system of the Krakatau volcano. Focal depth of the deepest events (~100 km) of the Krakatau cluster constrains the location of the primary magma generation to greater depths. The ascending magmatic fluids stress fault segments within the Sunda Strait fault zone and change their friction parameters inducing the observed tectonic earthquakes beneath Krakatau.

Keywords

Subduction-related volcanoes Krakatau Earthquake distribution Volcanic plumbing system 

Supplementary material

531_2010_543_MOESM1_ESM.pdf (119 kb)
Supplementary material 1 (PDF 118 kb)

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Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Aleš Špičák
    • 1
  • Jiří Vaněk
    • 1
  • Václav Hanuš
    • 1
  1. 1.Institute of Geophysics, Academy of Sciences of the Czech RepublicPraha 4Czech Republic

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