Bathymetry of the Indonesian Sunda margin-relating morphological features of the upper plate slopes to the location and extent of the seismogenic zone

Abstract

Abstract. Earthquake history shows that the Sunda subduction zone of the Indonesian margin produces great earthquakes offshore Sumatra, whereas earthquakes of comparable magnitude are lacking offshore Java and the Lesser Sunda islands. Morphological structures in multibeam bathymetric data across the forearc relate with the extent of the seismogenic zone.

The West Andaman Fault: A complex strain‐partitioning boundary at the seaward edge of the Aceh Basin, offshore Sumatra

“…A combined bathymetry grid (Figure b) allows us to extend our interpretation in space between the 2‐D seismic profiles and to correlate faults that exhibit a seafloor expression from profile to profile. These seafloor data consist of the bathymetry collected during the SUMUT survey, the grid from the German/Indonesian SEACAUSE and SUMATRA cruises [ Berglar et al ., ; Franke et al ., ; Krabbenhoeft et al ., ], and a grid acquired by the HMS Scott in 2005 [ Henstock et al ., ].…”

Seismoturbidite record as preserved at core sites at the Cascadia and Sumatra–Andaman subduction zones

“…Continental margin morphology west of Sumatra is dominated by the upper plate structure of a Tertiary and Quaternary accretionary prism with structural highs and forearc slope basins. Uplifted Tertiary-Quaternary Bengal and Nicobar fan sediments form the core of the duplexed accretionary prism offshore Sumatra, which acts as a local backstop (Fisher et al, 2007;Kopp et al, 2008;Singh et al, 2010;Krabbenhoeft et al, 2010). Topography here is controlled largely by the blocks of sediment up to 4 km thick (Bandopadhyay and Bandopadhyay, 1999;Fisher et al, 2007) uplifted from the India-Australia plate (likely by duplexing of the accretionary complex) to form the upper part of the accretionary prism and marginal plateau (Fisher et al, 2007).…”

Morphology of the Andaman outer shelf and upper slope of the Thai exclusive economic zone

“…In order to detect and characterize possible submarine landslides on the continental slope, detailed bathymetric data are required. At present such data are only available for the Central Basin of the Andaman Sea (Raju et al, 2004) and the southern part of the basin including parts of Mergui Ridge and Mergui Basin (Krabbenhoeft et al, 2010).…”

“…(b) Synthesis tectonic map of the East Andaman Basin redrawn fromCurray (2005) showing pull-apart extension fault in the Central Basin(Raju et al, 2004), strike slip faults with their approximate positions such as the Shan Scarp Fault and the Mergui Faults in the East Basin, strike-slip faults zone between Mergui Ridge and Ranong Ridge, the Ranong and the Klong Marui Fault(Richter et al, 1993;Polachan and Racey, 1993;Curray, 2005), and known detailed bathymetry(Raju et al, 2004;Krabbenhoeft et al, 2010). Boundary of Thai EEZ is shown by red line.…”