Sigsbee2 Models

Shot Records

Several sets of data were acquired on the Sigsbee models. The Madagascar repository contains one survey taken on the Sigsbee2A model which was performed with an absorbing surface boundary condition. Two surveys were conducted on the Sigsbee2B models one with a free surface boundary and one without.

The three surveys shared the same acquisition geometry. Each receiver recorded data every .008 seconds for 1 500 timesteps resulting in 12 seconds of data. A 7 950 m (26 100 ft) long streamer cable was deployed with 348 hydrophones spaced 22.86 m (75 ft) apart. Shots were fired every 45.72 m (150 ft) starting at 3 330 m (10 925 ft). Table 5 shows the values that Sigsbee shot headers should contain.

Standard
n1=1500	d1=0.008	o1=0	label1=Time	unit1=s
n2=348	d2=75	o2=0	label2=Offset	unit2=ft
n3=500 or 496	d3=150	o3=10925	label3=Shot-Coord	unit3=ft
Metric
n1=1500	d1=0.008	o1=0	label1=Time	unit1=s
n2=348	d2=.02286	o2=0	label2=Offset	unit2=km
n3=500 or 496	d3=.04572	o3=3.330	label3=Shot-Coord	unit3=km

Table 5. Appropriate header values for Sigsbee shot records. The number of shots; n3, varies slightly between the surveys

Sigsbee2 Models