能登半島西方沖の堆積作用・完新世堆積速度と活断層の活動間隔

概要

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Five sediment cores were collected from the shelf west of Noto Peninsula where the submarine active fault that generated the 2007 Noto-hanto earthquake is located, to clarify the activity of the fault. A total of 32 radiocarbon age determinations using molluscan and echinoderm shells sug-gested that the average sedimentation rate during the Holocene in the study area was around 200cm/ky. Judging from the sedimentation rate and sediment thickness above a ravinement surface, the age of the surface was calculated to be 11.6－15.8ka. This shows that the surface was formed according to the postglacial transgression after the last glacial maximum. Using the sedimentation rate, the fault activities recorded in the seismic reflection profiles occurred at around 2－3ky intervals in Holocene. Precise age determination allows us to estimate the ages of reflectors in the seismic reflection profiles and give us information on submarine fault activities.
東京大学の論文
2008-03-26