The intriguing paleogeodetic record of deformation
seen in the coral microatolls of the western Sumatra led
us to establish a network of continuously
recording GPS stations there. Between September
2002 and mid-2004 we established 14 stations in the region
of of our coral studies. After the December 2004 earthquake,
we established four additional stations farther north,
in Aceh and North Sumatra. We plan to construct ten more
stations by August 2005.
The coral and the GPS data are enabling more robust
modeling of the behavior of the subduction interface. We are
delineating more fully the nature of rupture during the 1797,
1833, 2004 and 2005 giant earthquakes and the nature of interseismic
and post-seismic slip on the interface (Sieh
et al., 2004; Chlieh
et al., 2004; Subarya et al., in press; Briggs et al., in
press).