10:05 AM - 10:20 AM
[SSS02-05] Chemical fingerprints of earthquake event deposits in the Japan Trench
Keywords:Paleoseismology, Japan Trench, event-stratigraphy
Three prominent seismo-turbidite sequences, related to the 2011 Tohoku-oki, the AD 869 Jogan and an earlier prehistoric earthquake, are widespread and exhibit in all records the same lithology as well as specific, unique elemental characteristics. In combination with reported rupture areas and incorporated calcareous nanno fossils, the deposited turbidity currents seem to originate from slope areas shallower than ~4500 m water depth. Further two chemical correlative seismo-turbidites have been deposited solely in an isolated basin in the deep trench and might be related to an historical earthquakes in AD 1454 (or AD 1611) and a prehistoric event ~2400 years BP. Other turbidite units do not reveal similarities in the elemental characteristics, but may also be the result of seismic triggered slope failures, deposited at locally restricted sites. It is observed that the frequency of turbidite deposition in the deep Japan Trench is higher during the past 1500 years, than during the period from ~15 ka to 2 ka, and might provide hints on the paleoseismic activity along the Japan Trench off Tohoku.