Sigsbee2 Models

Sigsbee Models

This model contains a sedimentary sequence broken up by a number of normal and thrust faults. Additionally, there is a complex salt structure found within the model that results in illumination problems when processing and migrating the data.

The Sigsbee2A model features an absorbing free surface condition and a weaker than normal water bottom reflection, resulting in data do not contain free surface multiples and less than normal internal multiples. The Sigsbee 2B model uses the same structural model as Sigsbee2A but the velocity contrast at the water bottom has been increased to a normal level thus generating significant internal and free surface multiples. Modeling on the 2B model was performed with both free and non free surface boundary conditions.

The Sigsbee2 models found in the Madagascar repository share the same dimensions and sampling rate. The model is 9.144 km (30 000 ft) in depth and 24.384 km (80 000 ft) in length. All the models contain 7.62 m (25 ft) grid spacing except for the migrated models that have 11.43 m (37.5 ft) lateral grid spacing. Throughout this article both standard and metric units will be presented in tabular form but all figures will exclusively utilize metric units.

Table 2 displays the correct values that Sigsbee2 model headers should contain.

Stratigraphic Models
Standard Units
n1=1201	d1=25	o1=0	label1=Depth	unit1=ft
n2=3201	d2=25	o2=10000	label2=Distance	unit2=ft
Metric Units
n1=1201	d1=.00762	o1=0	label1=Depth	unit1=km
n2=3201	d2=.00762	o2=3.048	label2=Distance	unit2=km
Migrated Models
Standard Units
n1=1201	d1=25	o1=0	label1=Depth	unit1=ft
n2=2133	d2=37.5	o2=10025	label2=Distance	unit2=ft
Metric Units
n1=1201	d1=.00762	o1=0	label1=Depth	unit1=km
n2=2133	d2=.0143	o2=3.055	label2=Distance	unit2=km

Table 2. Header information for Sigsbee2 models, note the initial offset in the horizontal direction and the coarse lateral sampling of the migrated models.

Sigsbee2 Models