Additional file 1 of Time-dependent modeling of slow-slip events along the Nankai Trough subduction zone, Japan, within the 2018–2023 period
Creators: name: Ozawa, Shinzaburo
name: Muneakane, Hiroshi
name: Suito, Hisashi
Publisher: name: figshare
Year: 2024
Subjects: subject: Geology
subject: FOS: Earth and related environmental sciences

description: Additional file 1.Figure S1.Horizontal viscoelastic relaxation. (a) Calculated horizontal post-seismic deformation owing to the viscoelastic relaxation associated with the 2011 Tohoku earthquake for the 2011–2022 period. (b) Calculated horizontal post-seismic deformation owing to the viscoelastic relaxation associated with the 2016 Kumamoto earthquake for the 2016–2022 period. The deformation in both panels was calculated using the Finite Element Method reported by Suito (2017a; 2017b). The blue circles indicate the Global Navigation Satellite System (GNSS) stations used in the network inversion filter (NIF). Figure S2.Trend period for each region. (1) March 1, 2008–March 1, 2011 (2) January 1, 2006–January 1, 2009 (3) January 1, 2006–January 1, 2009 (4) October 1, 2007–March 1, 2009 (5) January 1, 2006–January 1, 2009 (6) January 1, 2006–January 1, 2009 (7) January 1, 2006–January 1, 2008 (8) January 1, 2006–January 1, 2008 (9) January 1, 2007–January 1, 2009 (10) January 1, 2017–January 1, 2018 (11) January 1, 2017–January 1, 2019. Figure S3.(a) Estimated horizontal trends at GNSS sites. (b) Estimated vertical trends at GNSS sites. Figure S4.(a) Estimated trends based on observation (black) and computation (white). (b) Back slip estimated from the trends shown in (a). Figure S5.Checkerboard test. (a) Synthesized slip. (b) Inverted slip. Figure S6.Time evolution of the synthesized slip (blue) and inverted slip (black). The broken lines indicate 3σ at designated grids in Figure S5. Figure S7.Position time series for the sites in Figure 2 for longer periods. The red arrows indicate trend periods. Figure S8.Observation (black arrows) and computation (white arrows) of crustal deformation for the corresponding period in Figure 4. (a)–(f) Horizontal displacements. (g)–(l) Vertical displacements. Figure S9.Slip distribution for periods denoted by shaded areas in Figure 5(g). Star shows the epicenter of the 2019/5/10 Hyuga-nada earthquake. Figure S10.(a) Afterslip. (b)–(e) Slip distribution of possible short-term slow-slip events off Tanegashima. Star shows the epicenter of the 2019/1/8 Tanegashima earthquake. Figure S11.(a)–(f) Ground displacements for the corresponding transient periods (g) of the northern Hyuga-nada slow-slip event. Figure S12.(a) Position time series at site 021081 in north Kyushu after viscoelasticity correction. (b) Annual correction of (a). (c) Sign reversed time series of modeled viscoelastic relaxation. (d) Location of site 021081 (red circle). Figure S13.(a) Time evolution of the moment release of the afterslip of the 2019 Tanegashima earthquake (black line) and model computation for the entire period (red line). (b) Time evolution of the moment release of the afterslip of the 2019 Tanegashima earthquake (black line) and model computation before the occurrence of short-term slow-slip events.Figure S14.Position time series at sites 940083 and 021051. Figure S15.Observation (black dots) and computation (red line) at four stations in the Kii Peninsula. The eastward transients were observed at sites 041130, 021013, and 021012. Figure S16.(a) Horizontal displacements (black) and computation (white) at stations on the Kii Peninsula. (b) Vertical displacements (black) and computation (white) at stations in the Kii Peninsula. (c) Estimated aseismic slip for the 2018–2023 period. Figure S17.. Changes in Coulomb failure stress (ΔCFS) on the plate interface within the long-term slow-slip events within the 2018–2023 period. (a)–(f) Calculated ΔCFS values based on the aseismic slippage shown in Figure S18 (a)–(f).Figure S18.Aseismic slippage corresponding to changes in Coulomb failure stress (CFS) in (a)–(f) in Figure S17.