Scaling relations for seismic moment M0, rupture area S, average slip D, and asperity size Sa were obtained for large, great, and giant (Mw = 6.7–9.2) subduction‐zone earthquakes. We compiled the source parameters for seven giant (Mw~9) earthquakes globally for which the heterogeneous slip distributions were estimated from tsunami and geodetic data. We defined Sa for subfaults exhibiting slip greater than 1.5 times D. Adding 25 slip models of 10 great earthquakes around Japan, we recalculated regression relations for 32 slip models: S = 1.34 × 10−10 M02/3, D = 1.66 × 10−7 M01/3, Sa = 2.81 × 10−11 M02/3, and Sa/S = 0.2, where S and Sa are in square kilometers, M0 is in newton meters, and D is in meters. These scaling relations are very similar to those obtained by Murotani et al. (2008) for large and great earthquakes. Thus, both scaling relations can be used for future tsunami hazard assessment associated with a giant earthquake.

We applied a new method to compute tsunami Green's functions for slip inversion of the 1 April 2014 Iquique earthquake using both near-field and far-field tsunami waveforms. Inclusion of the effects of the elastic loading of seafloor, compressibility of seawater, and the geopotential variation in the computed Green's functions reproduced the tsunami traveltime delay relative to long-wave simulation and allowed us to use far-field records in tsunami waveform inversion. Multiple time window inversion was applied to tsunami waveforms iteratively until the result resembles the stable moment rate function from teleseismic inversion. We also used GPS data for a joint inversion of tsunami waveforms and coseismic crustal deformation. The major slip region with a size of 100 km × 40 km is located downdip the epicenter at depth~28 km, regardless of assumed rupture velocities. The total seismic moment estimated from the slip distribution is 1.24 × 10 21 N m (M w 8.0).

We proposed a source model for the 16 September 2015 Illapel (Chile) tsunamigenic earthquake using teleseismic and tsunami data. The 2015 epicenter was at the northernmost of the aftershocks zone of the 2010 Mw 8.8 Maule earthquake. Teleseismic body wave inversions and tsunami simulations showed optimum rupture velocities of 1.5–2.0 km/s. The agreement between observed and synthetic waveforms was quantified using normalized root‐mean‐square (NRMS) misfit. The variations of NRMS misfits were larger for tsunami data compared to the teleseismic data, because tsunami waveforms are more sensitive to the spatial distribution of slip. The large‐slip area was 80 km (along strike) × 100 km (along dip) with an average slip of 5.0 m and depth of 12–33 km, located ~70 km to the northwest of the epicenter. We obtained a seismic moment of 4.42 × 1021 Nm equivalent to Mw 8.4. Results may indicate a northward stress transfer from the 2010 Maule earthquake.

We characterized source rupture models with heterogeneous slip of plate-boundary earthquakes in the Japan region. The slip models are inferred from strong-motion, teleseismic, geodetic, or tsunami records. For the identification of asperities in the slip models, we found that the area of subfaults retrieved with slips of >1.5 times the total average slip provides a size approximately equivalent to the characterized asperity by Somerville et al. (1999). We then carried out regression analyses of the size and slip for the rupture area and asperity. The obtained scaling relationship to the seismic moment indicates that rupture area S, average slip D, and combined area of asperities S a are 1.4, 0.4, and 1.2 times larger, respectively, than those of crustal earthquakes. In contrast, the ratios of the size and slip between the asperities and rupture area (S a /S and D a /D) are the same for plateboundary earthquakes as for crustal earthquakes. The above analyses indicate that plate-boundary and crustal earthquakes share similar source characteristics.

The rupture process of the 1946 Nankai earthquake (M JMA 8.0) was estimated using seismic waveforms from teleseismic and strong motion stations together with geodetic data from leveling surveys and tide gauges. The results of joint inversion analysis showed that two areas with large slip are more confined than in previous studies. In our inversion, we assumed spatially varying strike and dip angles and depth of each subfault by fitting those to the actual complex shape of the upper surface of the Philippine Sea plate in the Nankai Trough region. As a result, we calculated the total seismic moment, M 0 = 5.5 × 10 21 Nm; the moment magnitude, M w = 8.4; and a maximum slip of 5.

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Teleseismic body wave analysis revealed that the 7 December 2012 off‐Sanriku earthquake (MW 7.3) at the outer rise of Japan Trench consisted of two successive subevents. The first subevent with reverse‐fault mechanism (Event 1, MW 7.1) at 56 km depth was followed by, approximately 20 s later, the second subevent with normal‐fault mechanism (Event 2, MW 7.2) at 6 km depth. Finite‐fault slip models show that the slip of Event 1 was concentrated around the initial rupture point with the maximum of 2.7 m and that Event 2 had two asperities with the maximum of 4.5 m at both sides of the initial rupture point. The static Coulomb Failure Function analyses suggested that Event 1 triggered Event 2 and that both subevents were promoted by the 2011 Tohoku earthquake (MW 9.1).

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