JpGU-AGU Joint Meeting 2017

Presentation information

[JJ] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS24] [JJ] Integrated Analysis of Geoscience Observations from the Floor to Surface of the Ocean

Mon. May 22, 2017 3:30 PM - 5:00 PM 202 (International Conference Hall 2F)

convener:Keisuke Ariyoshi(Japan Agency for Marine-Earth Science and Technology), Motoyuki Kido(International Research Institute for Disaster Science, Tohoku University), Daisuke Inazu(Tokyo University of Marine Science and Technology), Narumi Takahashi(National Research Institute for Earth Science and Disaster Resilience), Chairperson:Akira Kuwano-Yoshida(JAMSTEC), Chairperson:Akira Nagano(JAMSTEC)

3:30 PM - 3:45 PM

[MIS24-01] A total station plan combined with “Chikyu” and DONET: simultaneous observation from seafloor to atmosphere

*Keisuke Ariyoshi1, Akiko To1, Yuya Machida1, Shuhei Nishida1, Yasumasa Miyazawa1, Toru Miyama1, Akira Kuwano-Yoshida1, Hiroshi Uchida1, Akira Nagano1, Takuya Hasegawa1, Masahide Wakita1, Tatsu Kuwatani1, Kan Aoike1 (1.Japan Agency for Marine-Earth Science and Technology)

Keywords:subduction zone, megathrust earthquake, ocean current

DONET (Dense Oceanfloor Network system for Earthquakes and Tsunamis) has been developed and installed around Nankai Trough, which is motivated by the 2004 Sumatra-Andaman Earthquake. DONET contains pressure gauges as well as seismometers, which are expected to detect crustal deformations driven by peeling off subduction plate coupling process. From our simulation results, leveling changes are different sense among the DONET points even in the same science node. On the other hand, oceanic fluctuations such as melting ice masses through the global warming have so large scale as to cause ocean bottom pressure change coherently for all of DONET points especially in the same node. This difference suggests the possibility of extracting crustal deformations component from ocean bottom pressure data by differential of stacking data. However, this operation cannot be applied to local-scale fluctuations related to ocean mesoscale eddies and current fluctuations, which affect ocean bottom pressure through water density changes in the water column (from the sea surface to the bottom). Therefore, we need integral analysis by combining seismology, ocean physics and tsunami engineering so as to decompose into crustal deformation, oceanic fluctuations and instrumental drift, which will bring about high precision data enough to find geophysical phenomena. Since “Chikyu” has a plan of operation to connect borehole observations to DONET, we have to discuss the best way to do simultaneous observation from seafloor to atmosphere by taking advantage of this chance.

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