IS SCALING IN TURBIDITE DEPOSITION CONSISTENT WITH FORCING BY EARTHQUAKES

Two hypotheses have been suggested to explain the statistical distribu tion of bed thickness in turbidite sequences: that it is a reflection of turbidite triggering by earthquakes occurring haphazardly in time, and that it is controlled by the intrinsic, nonlinear dynamics of a se dimentary system composed of many downslope transport events that are correlated over a broad range of scales of length and time. In an atte mpt to distinguish between these hypotheses, we have applied five test s to two previously described, Oligocene turbidite sequences from the Izu-Bonin basin of the western Pacific Ocean. We conclude that turbidi te deposition in the Izu-Bonin region is not the outcome of a self-org anized process, nor of a low-dimensional, chaotic system, but Father i s consistent with turbidite emplacement by flows triggered by earthqua kes. At least some recent turbidites are known to have been deposited by such flows, and the tests we have applied demonstrate that no other process is required to explain the statistics of the thickness and th e timing of emplacement of beds in turbidite sequences, If turbidites are indeed related to earthquakes, then changes in the rate of turbidi te emplacement may be used to place important constraints on paleoseis micity.