Evaluation of the 2012 Indian Ocean Coseismic Fault Model
in 3-D Heterogeneous Structure based on Vertical and
Horizontal GNSS Observation
Cecep Pratama 1, a) Takeo Ito 1 Takao Tabei 2 Fumiaki Kimata 3 Endra Gunawan 4 Yusaku Ohta 5
Tadashi Yamashina 2 Irwandi Nurdin 6 Didik Sugiyanto 6 Umar Muksin 6 Nazli Ismail 6 Irwan Meilano 7
1 Graduate School of Environmental Studies, Nagoya University
D2-2(510), Furo-cho, Chikusa-ku, Nagoya-shi, Aichi, JAPAN 464-8601
2 Department of Applied Science, Faculty of Science, Kochi University
2-5-1 Akebono-cho, Kochi-shi, Kochi, JAPAN 780-8520
3 Tono Research Institute of Earthquake Science Applied Science
1-63 Akiyocho-cho, Yamanouchi, Mizunami-shi, Gifu, JAPAN 509-6132
4 Graduate Research on Earthquake and Active Tectonics, Bandung Institute of Technology
Jalan Ganesha 10, Bandung, West Java, INDONESIA 40132
5 Graduate School of Science, Tohoku University
6-3 Aramaki Aza-Aoba, Aoba-ku, Sendai JAPAN 980-8578
6 Faculty of Physics, Syiah Kuala University
Jalan Syech Abdurrauf no 3, Banda Aceh, Aceh, INDONESIA 23111
7 Faculty of Earth Sciences and Technology, Bandung Institute of Technology
Jalan Ganesha 10, Bandung, West Java, INDONESIA 40132
a) Corresponding author: cecep@seis.nagoya-u.ac.jp
Abstract. Lack of observation network in the vicinity of oceanic intraplate earthquake lead the estimation of coseismic fault slip with high uncertainty. Satriano et al. [2] and Wei et al. [3] found NNE trending left-lateral slip as the primary features. In another hand, Yue et al. [4] and Hill et al. [5] proposed WNW trending right-lateral faults structure as the main characteristic. Here, we investigate the coseismic fault model that could explain the coseismic offset both vertical and horizontal in a 3-D heterogeneous earth structure. We constructed finite element model that include three-dimensional velocity structure, topography/bathymetry, spherical-earth and subducting slab. In this study, we employed scaling slip to adjust slip amount and total seismic moment. Instead of original slip amount, we preserve seismic moment as a basis comparison. Based on vertical and horizontal observation data, WNW trending right-lateral fault could fit better than NNE trending left-lateral fault. The present study demonstrates best-fit calculation using scaling slip optimized to the horizontal or vertical observation lead the both fault model worsen the misfit of vertical or horizontal component, respectively. This result analysis indicates a trade-off between vertical and horizontal component and reflects he importance of revisiting the fault slip modeling incorporating vertical and horizontal data equally.
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