Several authors have recognized the Importance of anisotropy of the 

 sea floor to power spectral studies. Hayes and Conolly (1972) recog- 

 nized distinct peaks in their spectral analysis of the bathymetry of the 

 Australian-Antarctic Discordance. These groups were normalized to two 

 linear trends by projecting the data to simulate north-south and east- 

 west samples. Distinct trends were successfully identified, however, in 

 longer wavelengths than the high spatial frequency band of interest in 

 this study. Bell (1978) also recognized the importance of anisotropic 

 features in his study of abyssal hills in the north Pacific Ocean. One 

 result reported in his study of the aspect ratios of features in this 

 province is that the degree of anisotropy tends to decrease in the 

 higher spatial frequencies. Whether or not this is a true relationship 

 or the result of resolving limitations will be discussed further in 

 Chapter 6. 



Figure 4-7 shows the sample locations for two spectra from the lin- 

 ear Mendocino Fracture Zone In the northeastern Pacific Ocean. Figure 

 4-8 presents the profile and amplitude spectrum for line A-A' , which was 

 sampled perpendicular to strike, reflecting the long wavelength fracture 

 zone. Figure 4-9 is the corresponding plots for line B-B' , which paral- 

 lels strike and is located in the zone of disturbance. The exponential 

 form of both spectra is evident, however Figure 4-10, which shows a com- 

 posite of the trend of both spectra, illustrates the differences in 

 slope (exponent) of the two spectra. Segment A-A' contains more power 

 in the low spatial frequencies, while segment B-B' contains more power 

 in the high spatial frequencies. 



Both spectra are valid representations of the spatial frequency 

 distribution in this physiographic province, but neither spectrum indi- 



35 



