Detectability analysis of interplate fault slips in the Nankai subduction thrust using seafloor observation instruments
To help the decision making regarding where to locate new observation instruments on the seafloor, we examined the detectability of interplate earthquakes and slow slips in the Nankai subduction thrust in Japan using seafloor observation instruments. Here, the detectability is defined as the smallest magnitude of the interplate fault slip detected by the assumed observation points based on crustal deformation simulation. In the detectability analyses, we considered the effect of sensor drifts that are particularly associated with seafloor observations. In addition, we introduced high-resolution three-dimensional (3D) finite element modeling of crustal deformation to consider the effect of the topography and 3D heterogeneous crustal structure around the Nankai Trough. The results of the detectability analyses show that introducing new seafloor stations for tilt observation in the Nankai region should increase the detectability of small- or medium-sized interplate earthquakes and slow slips significantly. Based on the obtained results, we also discuss the advantage of both the existing and the new observation instruments in detecting interplate fault slips.
KeywordsSlow slips Detectability analysis Seafloor observation instruments Tilt observation Ocean bottom pressure gauge DONET Finite element analysis Crustal deformation
Part of the results were obtained using the K computer at the RIKEN Advanced Institute for Computational Science (Proposal No.: hp170249 and hp180207). This work was supported by Post K computer project (Priority issue 3: development of integrated Simulation Systems for Hazard and Disaster Induced by Earthquake and Tsunami).
- Agata R, Ichimura T, Hirahara K, Hyodo M, Hori T, Hashimoto C, Hori M (2013) Fundamental research for improving fault scenario -development of a method for crustal deformation analysis using high-fidelity three-dimensional crustal structure-(in Japanese with English abstract). J Jpn Soc Civil Eng Ser 69(6343):I\_767–I\_776Google Scholar
- Aki K (1966) Generation and propagation of G waves from the Niigata Earthquake of June 16, 1964. Part 2. Estimation of earthquake movement, released energy, and stress-strain drop from the G wave spectrum. Bull Earthq Res Inst 44:73–88Google Scholar
- Citak SO, Nakamura T, Nakanishi A, Yamamoto Y, Ohori M, Baba T, Kaneda Y (2012) An Updated Model of Three-dimensional Seismic Structure in the Source Area of the Tokaitonankai- nankai Earthquake. In: AOGS-AGU(WPGM) Joint AssemblyGoogle Scholar
- Kanamori H, Anderson DL (1975) Theoretical basis of some empirical relations in seismology. Bull Seismol Soc Am 65(5):1073–1095Google Scholar
- Kaneda Y, Kawaguchi K, Araki E, Matsumoto H, Nakamura T, Kamiya S, Ariyoshi K, Hori T, Baba T, Takahashi N (2015) Development and application of an advanced ocean floor network system for megathrust earthquakes and tsunamis. In: Favali P, Beranzoli L, De Santis A (eds) Seafloor observatories. Springer, Berlin, pp 643–662CrossRefGoogle Scholar
- Kaneda Y, Kawaguchi K, Araki E, Sakuma A, Matsumoto H, Nakamura T, Kamiya S, Ariyoshi K, Baba T, Ohori M et al (2009) Dense Ocean floor Network for Earthquakes and Tsunamis (DONET)-Development and Data application for the mega thrust earthquakes around the Nankai trough. 1:1453Google Scholar
- Machida Y, Nishida S, Araki E, Matsumoto H, Kimura T, and Kawaguchi K (2016) Assessments of a quartz pressure sensor characteristics for accurate pressure measurements to detect small seafloor displacements. In: IEEE Techno-Ocean (Techno-Ocean), pp 652–655Google Scholar
- Melosh H, Raefsky A (1981) A simple and efficient method for introducing faults into finite element computations. Bull Seismol Soc Am 71(5):1391–1400Google Scholar
- Miyazaki H, Kusano Y, Shinjou N, Shoji F, Yokokawa M, Watanabe T (2012) Overview of the K computer system. Fujitsu Sci Tech J 48(3):255–265Google Scholar
- Obara K (2010) Phenomenology of deep slow earthquake family in southwest Japan: spatiotemporal characteristics and segmentation. J Geophys Res Solid Earth 115(B8):1–22Google Scholar
- Okada Y (1992) Internal deformation due to shear and tensile faults in a half-space. Bull Seismol Soc Am 82(2):1018–1040Google Scholar
- Suito H (2017) Detectability of interplate fault slip around Japan, based on GEONET daily solution F3 (in Japanese with English abstract). J Geod Soc Jpn 62(3):109–120Google Scholar