This research combines geological data obtained from core samples and geophysical properties in order to investigate how geological and sedimentological parameters affect the velocity of P-waves in near surface marine sediments, The velocity of P-waves (Vp), gamma density, acoustic impedance and magnetic susceptibility were correlated with core geology of four core of the coastal region of Caravelas, Bahia State. Geophysical properties were acquired using the MSCL (MultiSensor Core Logger). Core were opened and described according to grain size, color, compaction degree. Eight different kinds of sediments were recognized: shell, coarse to very coarse sand, medium sand, fine to very fine sand, sandy mud, compact mud, fluid mud, and very fluid mud. The results showed that, in general, the highest values of Vp and density and the lowest values of magnetic susceptibility are related to the coarser sediments. Very coarse sediments and shells showed erratic values basically due to the low compaction of these materials. The acoustic impedance and reflection coefficient profiles were useful to detect sediments interface. More detailed grain size analysis were conducted at the sandy mud section of core JP-112 and corroborated the relationship between Vp and grain size.
P-wave velocity; magnetic susceptibility; shallow sediments; Caravelas
