Long-period ocean-bottom motions in the source areas of large subduction earthquakes

Takeshi Nakamura, Hiroshi Takenaka, Taro Okamoto, Michihiro Ohori, Seiji Tsuboi

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Long-period ground motions in plain and basin areas on land can cause large-scale, severe damage to structures and buildings and have been widely investigated for disaster prevention and mitigation. However, such motions in ocean-bottom areas are poorly studied because of their relative insignificance in uninhabited areas and the lack of ocean-bottom strong-motion data. Here, we report on evidence for the development of long-period (10-20 s) motions using deep ocean-bottom data. The waveforms and spectrograms demonstrate prolonged and amplified motions that are inconsistent with attenuation patterns of ground motions on land. Simulated waveforms reproducing observed ocean-bottom data demonstrate substantial contributions of thick low-velocity sediment layers to development of these motions. This development, which could affect magnitude estimates and finite fault slip modelling because of its critical period ranges on their estimations, may be common in the source areas of subduction earthquakes where thick, low-velocity sediment layers are present.

Original languageEnglish
Article number16648
JournalScientific Reports
Volume5
DOIs
Publication statusPublished - Nov 30 2015

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subduction
seafloor
earthquake
ground motion
fault slip
strong motion
sediment
mitigation
damage
basin
modeling
land

ASJC Scopus subject areas

  • General

Cite this

Long-period ocean-bottom motions in the source areas of large subduction earthquakes. / Nakamura, Takeshi; Takenaka, Hiroshi; Okamoto, Taro; Ohori, Michihiro; Tsuboi, Seiji.

In: Scientific Reports, Vol. 5, 16648, 30.11.2015.

Research output: Contribution to journalArticle

Nakamura, Takeshi ; Takenaka, Hiroshi ; Okamoto, Taro ; Ohori, Michihiro ; Tsuboi, Seiji. / Long-period ocean-bottom motions in the source areas of large subduction earthquakes. In: Scientific Reports. 2015 ; Vol. 5.
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