Source process with heterogeneous rupture velocity for the 2011 Tohoku-Oki earthquake based on 1-Hz GPS data

Abstract

Abstract:A rupture model with varying rupture front expansion velocity for the March 11, 2011, Tohoku-Oki earthquake was obtained by the joint inversion of high-rate Global Positioning System (GPS) data and ocean bottom GPS/acoustic (OB-GPS) data. The inverted rupture velocity with a complex distribution gradually increases near the hypocenter and shows rapid rupture expansion at the shallowest part of the fault. The entire rupture process, which lasted 160 s, can be divided into three energy release stages, based on the moment rate function. The preferred slip model, showing a compatible relationship with aftershocks, has a primary asperity concentrated from the hypocenter to the trench and a small asperity located on the southern fault. Source time functions for subfaults and temporal rupture images suggest that repeated slips occurred in the primary rupture, which is consistent with that from seismic waveforms. Our estimated maximum slip and total seismic moment are ~65 m and 4.2 × 10 22 Nm (Mw 9.0), respectively. The large slip, stress drop, and rupture velocity are all concentrated at shallow depths, which indicates that the shallow part of the fault radiated high-frequency as well as low-frequency seismic waves.

Rapid Estimation of Earthquake Magnitude and Source Parameters Using Genetic Algorithms

“…However, the estimated result of each source parameter (length, width, rake, and slip) shown in Table 5 was reasonable according to the 2011 Tohoku Oki earthquake's source model described and analyzed in previous research [40][41][42]. Some fault plane models analyzed in previous research ranged from 600 to 812 km in length and from 109 to 240 km in width [41,42], while the results estimated in this study used 668 km for the length parameter and 234 km for the width parameter in the third fault model tested. The range of estimated width parameter values that resulted from this study was between 153 to 234 km.…”

“…The range of estimated width parameter values that resulted from this study was between 153 to 234 km. The slip estimation value ranged between 25 and 60 m in most previous research [40,41], while this study estimated slips in the range of 10 to 24.598 km.…”

A Decade of Lessons Learned from the 2011 Tohoku‐Oki Earthquake

“…The coseismic slip of the Tohoku‐oki earthquake was estimated from seismic waveform data (Ammon et al., 2011; Hayes, 2011; Ide et al., 2011; Satriano et al., 2014; Shao et al., 2011; Suzuki et al., 2011; Uchide, 2013; Yagi & Fukahata, 2011; Yoshida et al., 2011), geodetic surface deformation measurements (Iinuma et al., 2012; Ito, et al., 2011; Kyriakopoulos et al., 2013; Ozawa et al., 2012; Perfettini & Avouac, 2014; Pollitz et al., 2011; Silverii et al., 2014; Zhou et al., 2014), high‐rate GPS time series (Wang et al., 2016; Yue & Lay, 2011), tsunami wave observations (Fujii et al., 2011; Hossen et al., 2015; Maeda et al., 2011; Saito et al., 2011; Satake et al., 2013), InSAR, and various combinations of these data (Bletery et al., 2014; Gusman et al., 2012; Hooper et al., 2013; Koketsu et al., 2011; Kubo & Kakehi, 2013; Lee et al., 2011; Melgar & Bock, 2015; Minson et al., 2014; Romano et al., 2012, 2014; Wang et al., 2012; Wang et al., 2013; Wei et al., 2012; Yamazaki et al., 2018; Yokota et al., 2011; Yue & Lay, 2013) (Figure 12). Resolution tests of models constrained by individual datasets indicate that the strong motion data alone have limited resolution of slip updip from the hypocenter, while inversions of on‐land static geodetic data can resolve slip out to the hypocenter but have no resolution of slip near the trench (Wei et al., 2012).…”

“…Then, substantial slip continued for more than 100 s in the updip shallow part of the plate boundary (Wang et al., 2016). Some studies suggest repeated rupture of some sections occurred in this shallow updip area (Ide et al., 2011; Lee et al., 2011; Wang et al., 2016). The large slip area reaching to the trench produced seafloor uplift that caused the tsunami and led to the high tsunami runup along the Sanriku Coast and wide inundation in the Sendai plane (Mori et al., 2011; Nakajima & Koarai, 2011).…”

Interplate channel layer controls of slip during and after the 2011 Tohoku-Oki earthquake

“…Seismic and geodetic data have demonstrated that the large coseismic slip in the shallow area that caused the 2011 Tohoku-Oki earthquake was limited to the middle segment 2,3,4 . Additionally, paleoseismological evidence collected along the Japan Trench demonstrated that deep-sea turbidites that originated from large earthquakes potentially similar to the 2011 Tohoku-Oki earthquake are recorded only in the middle segment 5 .…”