We investigate thalamo-cortical systems that are modeled by nonlinear Volterra integro-differential equations of convolution type. We divide the systems into smaller subsystems in such a way that each of them is solved separately by a processor working independently of other processors results of which are shared only once in the process of computations. We solve the subsystems concurrently in a parallel computing environment and present results of numerical experiments, which show savings in the run time and therefore efficiency of our approach. For our numerical simulations, we apply different numbers np of processors and each case shows that the run time decreases with increasing np. The optimal speed-up is obtained with np=N, where N is the (moderate) number of equations in the thalamo-cortical model.

Geotechnical boreholes drilled on the north and south river banks detected a laterally varying soil profile. The south-bank hole encountered 9.1 m of granular overburden, followed by 8.5 m of silt with bands of siltstone and arkosic sandstone. The north-bank hole encountered 13.5 m of granular overburden, followed by 4.5 m of arkosic sandstone. The seismic down-hole survey (south bank) determined that the compacted silt was 2.5 times stiffer than the granular overburden. The damping value of the silt was 80% of the granular soil’s damping.

The author interprets subsurface and geophysical data as a granular overburden resting on an angular unconformity. The unconformity truncates layers of silt, siltstone, and arkosic sandstone dipping 19 to 25 degrees down to the north. Hard layers subcropped by the interpreted unconformity have produced two topographic highs on the refractor. Engineers should expect less granular overburden and more resistance to driving H-piles at these locations.

It appears that, in the case of unsaturated soils, the relatively low level of viscous damping in shear may be explained by the low mass of the air in the pores. That is, it is difficult for inertial decoupling to occur between the soil frame and the pore fluid when the pore fluid (air) is of such low density. Thus, a pore fluid in coupled motion with the frame can not produce significant viscous drag. On the other hand, large viscous damping is observed for compressional waves. This larger damping may be due to the larger relative motions between air and frame which can be forced by compression of the frame matrix. These observations may be relevant in areas such as the design of driven piles and the estimation of potential for damages from vibrations due to construction.

In 1994, a seismic refraction study was commissioned by Idaho Power Company to help HAFO upgrade its resource protection program through the identification of additional monitoring well locations. These monitoring wells would also have the potential for serving as dewatering wells. The refraction study was successful in mapping the extent and structure of the Shoestring Road Basalt in the area of the Fossil Gulch Canal and the Horse Quarry. Results of this study suggest that the orientation of the basalt flow funnels the ground waters from the leaking canal towards the cliffs containing the fossil beds.

Significant findings include the following. First, subtraction of oppositely polarized source efforts improves the PCA formulation by enhancing the S-waves. Second, the Swave enhancement is improved by scaling the oppositely polarized source efforts by the vertical (not horizontal) component data, as this provides a better attenuation of non-Swave energy. Third, observation of the tool orientation as it exits the borehole is helpful in resolving the 180 degree azimuthal ambiguity in the PCA approach. Finally, the polarization of the source radiation may drift relative to the axis of the source during a survey, and should not be assumed invariant.