02554nas a2200265   4500000000100000008004100001653001600042653001500058653001400073653001900087653002200106653002300128100001700151700001500168700001800183700001800201700001200219700001900231245011500250856005100365300002100416490000800437520182900445022001402274       2016                            d10aEarthquakes10aGeohazards10asea level10aSediment cores10aSubmarine canyons10aturbidity currents1 aJoshua Allin1 aJames Hunt1 aPeter Talling1 aMichael Clare1 aEd Pope1 aDouglas Masson00aDifferent frequencies and triggers of canyon filling and flushing events in Nazar\ e Canyon, offshore Portugal  uhttp://dx.doi.org/10.1016/j.margeo.2015.11.005  a89\textendash1050 v3713 a<p>Submarine canyons are one of the most important pathways for sediment transport into ocean basins. For this reason, understanding canyon architecture and sedimentary processes has importance for sediment budgets, carbon cycling, and geohazard assessment. Despite increasing knowledge of turbidity current triggers, the down-canyon variability in turbidity current frequency within most canyon systems is not well constrained. New AMS radiocarbon chronologies from canyon sediment cores illustrate significant variability in turbidity current frequency within Nazar\ e Canyon through time. Generalised linear models and Cox proportional hazards models indicate a strong influence of global sea level on the frequency of turbidity currents that fill the canyon. Radiocarbon ages from basin sediment cores indicate that larger, canyon-flushing turbidity currents reaching the Iberian Abyssal Plain have a significantly longer average recurrence interval than turbidity currents that fill the canyon. The recurrence intervals of these canyon-flushing turbidity currents also appear to be unaffected by long-term changes in global sea level. Furthermore, canyon-flushing and canyon-filling have very different statistical distributions of recurrence intervals. This indicates that the factors triggering, and thus controlling the frequency of canyon-flushing and canyon-filling events are very different. Canyon-filling appears to be predominantly triggered by sediment instability during sea level lowstand, and by storm and nepheloid transport during the present day highstand. Canyon-flushing exhibits time-independent behaviour. This indicates that a temporally random process, signal shredding, or summation of non-random processes that cannot be discerned from a random signal, are triggering canyon flushing events.</p>  a0025-3227