JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Poster

S (Solid Earth Sciences) » S-SS Seismology

[S-SS04] [EE] Subduction zone dynamics from regular earthquakes through slow earthquakes to creep

Wed. May 24, 2017 3:30 PM - 5:00 PM Poster Hall (International Exhibition Hall HALL7)

convener:Kyuichi Kanagawa(Graduate School of Science, Chiba University), Kazushige Obara(Earthquake Research Institute, The University of Tokyo), Demian M Saffer(Pennsylvania State University), Laura Wallace(University of Texas Institute for Geophysics)

[SSS04-P42] Spatial distribution of long-term slow slip events beneath the Bungo Channel under sparsity constraints

*Ryoko Nakata1, Hideitsu Hino2, Tatsu Kuwatani3, Shoichi Yoshioka4, Masato Okada5, Takane Hori1 (1.R & D Center for Earthquake and Tsunami, Japan Agency for Marine-Earth Science and Technology, 2.University of Tsukuba, 3.Department of Solid Earth Geochemistry, Japan Agency for Marine-Earth Science and Technology, 4.Kobe University, 5.The University of Tokyo)

It is possible that generation mechanisms of slow earthquakes are affected by certain physical and/or chemical thresholds. However, up-dip and down-dip limits of long-term slow slip events have previously been assumed to be smoothly distributed because of prior constraints to inversion analyses. We have applied an inversion method called generalized fused lasso, a type of sparsity constraint, for evaluation function. We analyzed realistic displacement data for long-term slow slip events (L-SSEs) observed at GEONET stations around the Bungo Channel, southwest Japan. Using fused regularization, we estimated the slip distribution of three L-SSEs that occurred on 1997, 2003, and 2010. As a result, we identified three discontinuous boundaries on the subducting plate interface. These findings will help to reveal the transition mechanism from megathrust earthquakes to slow earthquakes on the subducting plate interface.