Significant tsunami observed at ocean-bottom pressure gauges during the 2011 off the Pacific coast of Tohoku Earthquake (original) (raw)
Related papers
2011
This study was undertaken with reference to the J apan earthquake of 11 March 2011. The aim of the study is to simulate the wave propagation of the tsunami of this earthquake, by comparing with the available deep ocean pressure se nsors (DART) and tide gauge records. Nonlinear shallow water equations are solved with a finite di fference scheme, using a computational grid with different cell sizes over GEBCO30 bathymetry data. Co-seismic source models proposed by different organizations and researchers were carried out to e xplain the tsunami propagation. The source models were used to model the deformation on sea bottom which is translated directly to the water surface. The approach is based on the dislocation algorithm for a finite rectangular fault and empirical scalin g laws for earthquake sources. Based on the various s ource models, arrival times and maximum wave heights are presented here followed by the analysis of the results. The assumption of the average uniform slip model...
Tsunami source of the 2011 off the Pacific coast of Tohoku Earthquake
Earth, Planets and Space, 2011
Tsunami waveform inversion for the 11 March, 2011, off the Pacific coast of Tohoku Earthquake (M 9.0) indicates that the source of the largest tsunami was located near the axis of the Japan trench. Ocean-bottom pressure, and GPS wave, gauges recorded two-step tsunami waveforms: a gradual increase of sea level (∼2 m) followed by an impulsive tsunami wave (3 to 5 m). The slip distribution estimated from 33 coastal tide gauges, offshore GPS wave gauges and bottom-pressure gauges show that the large slip, more than 40 m, was located along the trench axis. This offshore slip, similar but much larger than the 1896 Sanriku "tsunami earthquake," is responsible for the recorded large impulsive peak. Large slip on the plate interface at southern Sanriku-oki (∼30 m) and Miyagi-oki (∼17 m) around the epicenter, a similar location with larger slip than the previously proposed fault model of the 869 Jogan earthquake, is responsible for the initial water-level rise and, presumably, the large tsunami inundation in Sendai plain. The interplate slip is ∼10 m in Fukushima-oki, and less than 3 m in the Ibaraki-oki region. The total seismic moment is estimated as 3.8 × 10 22 N m (M w = 9.0).
Earth, Planets and Space, 2011
Finite-source rupture models for the great 11 March 2011 off the Pacific coast of Tohoku (M w 9.0) Earthquake obtained by inversions of seismic waves and geodetic observations are used to reconstruct deep-water tsunami recordings from DART buoys near Japan. One model is from least-squares inversion of teleseismic P waves, and another from iterative least-squares search-based joint inversion of teleseismic P waves, short-arc Rayleigh wave relative source time functions, and high-rate GPS observations from northern Honshu. These rupture model inversions impose similar kinematic constraints on the rupture growth, and both have concentrations of slip of up to 42 m up-dip from the hypocenter, with substantial slip extending to the trench. Tsunami surface elevations were computed using the model NEOWAVE, which includes a vertical momentum equation and a non-hydrostatic pressure term in the nonlinear shallow-water equations to account for the time-history of seafloor deformation and propagation of weakly dispersive tsunami waves. Kinematic seafloor deformations were computed using the Okada solutions for the rupture models. Good matches to the tsunami arrival times and waveforms are achieved for the DART recordings for models with slip extending all the way to the trench, whereas shifting fault slip toward the coast degrades the predictions.
2016
obtained by inversions of seismic waves and geodetic observations are used to reconstruct deep-water tsunami recordings from DART buoys near Japan. One model is from least-squares inversion of teleseismic P waves, and another from iterative least-squares search-based joint inversion of teleseismic P waves, short-arc Rayleigh wave relative source time functions, and high-rate GPS observations from northern Honshu. These rupture model inversions impose similar kinematic constraints on the rupture growth, and both have concentrations of slip of up to 42 m up-dip from the hypocenter, with substantial slip extending to the trench. Tsunami surface elevations were computed using the model NEOWAVE, which includes a vertical momentum equation and a non-hydrostatic pressure term in the nonlinear shallow-water equations to account for the time-history of seafloor deformation and propagation of weakly dispersive tsunami waves. Kinematic seafloor deformations were computed using the Okada soluti...
Advances in Natural and Technological Hazards Research, 2005
Tsunami height survey was conducted immediately after the 2003 Tokachi-oki earthquake. Results of the survey show that the largest tsunami height was 4 m to the east of Cape Erimo, around Bansei-onsen, and locally at Mabiro. The results also show that the tsunami height distribution of the 2003 Tokachi-oki earthquake is clearly different from that of the 1952 Tokachi-oki earthquake, suggesting the different source areas of the 1952 and 2003 Tokachioki earthquakes. Numerical simulation of tsunami is carried out using the slip distribution estimated by . The overall pattern of the observed tsunami height distribution along the coast is explained by the computed ones although the observed tsunami heights are slightly smaller. Large later phase observed at the tide gauge in Urakawa is the edge wave propagating from Cape Erimo along the west coast of the Hidaka area.
Potential tsunamigenic faults of the 2011 off the Pacific coast of Tohoku Earthquake
Earth, Planets and Space, 2011
Faults related to the tsunamigenic 2011 Tohoku-Oki Earthquake (M w 9.0) were investigated by using multichannel seismic reflection data acquired in 1999 and submersible seafloor observations from 2008. The location of the fault system interpreted in the seismic reflection profile is distributed around the area with largest slip and tsunami induction of the 2011 event. Cold-seep communities along the trace of the branch reverse fault and a high scarp associated with the trace of a normal fault suggest current activity on these faults. We interpret the fault system in the seismic profile as a shallow extension of the seismogenic fault that may have contributed to the resulting huge tsunami.
Earth, Planets and Space, 2004
We estimate the tsunami source area of the 2003 Tokachi-oki earthquake (Mw 8.0) from observed tsunami travel times at 17 Japanese tide gauge stations. The estimated tsunami source area (∼1.4 × 10 4 km 2 ) coincides with the western-half of the ocean-bottom deformation area (∼2.52 × 10 4 km 2 ) of the 1952 Tokachi-oki earthquake (Mw 8.1), previously inferred from tsunami waveform inversion. This suggests that the 2003 event ruptured only the western-half of the 1952 rupture extent. Geographical distribution of the maximum tsunami heights in 2003 differs significantly from that of the 1952 tsunami, supporting this hypothesis. Analysis of first-peak tsunami travel times indicates that a major uplift of the ocean-bottom occurred approximately 30 km to the NNW of the mainshock epicenter, just above a major asperity inferred from seismic waveform inversion.