Abstract - Good quality 2-D and 3-D seismic data
from the Timor Sea are used to determine the three dimensional geometry,
displacement patterns and development of intersecting conjugate normal
faults. These data are supplemented by data from previous physical modelling
studies. Conjugate structures, which comprise two intersecting opposed-dipping
normal faults or fault sets, form synchronously on a geological time scale
and develop due to the incidental intersection of the faults. Factors which
affect both the formation and imaging of these structures include: the
fault density, the spatial distribution of opposed-dipping faults, the
seismic resolution and the vertical extent of the imaged fault data. Large
conjugate structures grow from smaller ones; larger conjugates are associated
with more numerous and larger faults than small structures. On the scale
of the seismic data (fault throws range from ca 10-400m), synchronous fault
movements are accommodated by a reduction of displacements on discrete
fault surfaces towards the fault intersection zone, and a corresponding
increase in ductile strain of this region. High strains in the volume proximal
to the fault intersection zone are expressed as thinning of stratigraphic
units between the conjugate faults, and are believed to be accommodated
by numerous small sub-seismic faults. Intersection of two opposed-dipping
faults does not prevent their continued synchronous movement and does not
result in mechanical locking of the system.
Journal of Structural Geology 17, 847-862, 1995.