Index properties measurements were made at a resolution of one sample every two sections in the cores from Holes 1122A and 1122C. Index properties were determined by a gravimetric method (see "Physical Properties" in the "Explanatory Notes" chapter). Values of measured index properties (void ratio, porosity, water content, bulk density, and grain density) are presented in Table T15 (also in ASCII format). The properties measured from Holes 1122A and 1122C show cyclic variations downcore resulting from compositional variations typical of turbidite sequences (Figs. F34, F35). In the upper 500 mbsf, there is no apparent change in trend for any of the variables measured. Below 500 mbsf, the index properties show gradual downhole changes in trend, presumably from the effects of increased overburden.
The shipboard physical properties program at Site 1122 included nondestructive measurements of bulk density, magnetic susceptibility, and natural gamma-ray activity on whole sections of all cores using the MST (Figs. F36, F37). Magnetic susceptibility was measured at 4-cm intervals and at high sensitivity (4-s measurement time) in all Site 1122 holes. High-amplitude fluctuations of magnetic susceptibility in Hole 1122A and in the upper part (<110 mbsf) of Hole 1122C are associated with turbidite sequences. The presence of low magnetic susceptibility values with little variation below 110 mbsf in Hole 1122C is probably a result of low recovery of sands by XCB coring. Thus, there is a tendency for recovered core material to be clay rich. Natural gamma radiation was measured with a 15-s count every 14 cm in Holes 1122A and 1122C. Natural gamma radiation ranges from 15 to 42 counts/s. Variations occurring downcore reflect changes in mineral composition between sandy and clayey layers in the turbidite sequence. High values of natural gamma radiation give an indication of the relative abundance of clay. Low natural gamma radiation values shown in Hole 1122A are correlated with low magnetic susceptibility, indicating a possible increase in sand content. Gamma-ray attenuation porosity evaluator bulk density measurements were made at 4-cm intervals at all Site 1122 holes. The GRAPE density data exhibit fluctuations that tend to vary in direction, thickness, and intensity with those observed in the natural gamma radiation record; these fluctuations seem to correspond to variations in the occurrence of sandy and clay-rich sediment layers. A comparison of GRAPE density with the wet-bulk density determined from discrete samples shows a general agreement except in the uppermost part of the hole (Fig. F38).
Measurements of shear strength, using a mechanical vane, were made on split cores from Holes 1122A and 1122C (Fig. F39). Samples were generally taken in fine-grained sediments at a resolution of one per section. No samples were taken from XCB cores. The shear strength measurements show relatively low values, except for peaks just above 35 and 65 mbsf in Hole 1122A and 42, 69, and 92 mbsf in Hole 1122C. These peaks indicate clay-rich intervals (see "Lithostratigraphy"). Shear strength values range from 5 to 60 kPa (maximum value of 57.15 kPa at 65 mbsf in Hole 1122A and 60.525 kPa at 91 mbsf in Hole 1122C). Low values may be associated with the presence of sand-rich intervals (see "Lithostratigraphy"). An indication of the consolidation characteristics of the sediments was made by using the classical relationship between shear strength and sedimentary overburden pressure (see "Physical Properties" in the "Site 1121" chapter). The consolidation data from Site 1122 are similar in character to those from Site 1119 where cyclic variations also occur. Underconsolidation exists downhole as a result of rapid, increasingly sandy deposition. It is likely that the sediment is still undelrconsolidated, that is, still in the process of expelling pore water. The fact that water content and porosity remain relatively constant throughout the section supports this hypothesis.
Compressional-wave (P-wave) velocity was measured parallel to the core axis on split cores from Site 1122. Because the sediment cracked when the transducers of the Digital Sound Velocimeter were inserted into the sandy turbidite sediment, the measurements were only taken in the upper 20 mbsf of Hole 1122A. Values range from 1527 m/s to 1547 m/s. Below 390 mbsf in Hole 1122C, sediments were more tightly compacted, and the Hamilton frame velocimeter was used to measure sound propagation perpendicular to the sediment. A sharp increase in P-wave velocity from 1800 to 2000 m/s occurred around 429 mbsf between Sections 181-1122C-48X-2 and 48X-3, indicating a distinct lithologic horizon.