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Title
Earthquake, Gravity, and the Origin of the Bali Basin: An Example of a Nascent Continental Fold-and-Thrust Belt.
File
ADA178191.pdf
Author(s)
McCaffrey, R.; Nabelek, J.
Source
Air Force Geophysics Lab., Hanscom AFB, MA., January 10, 1987, 22 p.
Abstract
We infer from the bathymetry and gravity field and from the source mechanisms and depths of the eight largest earthquakes in the Bali region that the Bali Basin is a downwarp in the crust of the Sunda Shelf produced and maintained by thrusting along the Flores back arc thrust zone. Earthquake source mechanisms and focal depths are inferred from the inversion of long-period P and SH waves for all events and short-period P waves for two of the events. The present tectonic setting and structure of the Bali Basin is comparable to the early forelands of the Andes or western North America in that a fold-and-thrust belt is forming on the continental side of an arc-trench system at which oceanic lithosphere is being subducted. The Bali Basin is flanked by the Tertiary Java Basin to the west and the oceanic Flores Basin to the east and thus provides an actualistic setting for the development of a fold-and-thrust belt in which structure and timing of deformation can change significantly along strike on the scale a few hundred kilometers.
Keywords
North america; Depth; Deformation; Seismic waves; Indonesia; Short range (Time); Subduction zones; Sources; Tectonics; Continental drift; Lithosphere; Ocean bottom topography; Basins (Geographic); Gravitational fields; Thrust; Reprints; Oceanic crust; Bathymetry; East (Direction); Bali basin; Gravity; Ocean basins; Primary waves (Seismic waves); Earthquakes