Near-field tsunami forecasting using offshore tsunami data from the 2011 off the Pacific coast of Tohoku Earthquake

Abstract

Tsunami heights greater than 4 m were observed at several coastal tide-gauge stations during the tsunami generated by the 2011 off the Pacific coast of Tohoku Earthquake (M w 9.0), causing thousands of casualties and damaging infrastructure along the Pacific coast of Japan. We retrospectively applied an algorithm of nearfield tsunami forecasting to tsunami data that were recorded at various offshore tsunami stations 5-10 min before the tsunami reached the coastal tide-gauge stations nearest to its source. We inverted the waveform data recorded offshore to estimate the distribution of the initial sea-surface height, and then tsunami waveforms were synthesized from the estimated source to forecast tsunami arrival times and amplitudes at coastal tide-gauge stations. As a result of a retrospective application made 20 min after the earthquake, tsunamis with heights of 6-14 m were forecasted at tide-gauge stations nearest to the source where the sea-level increase due to the actual tsunami began to exceed 1 m after an elapsed time of 25 min. The result suggests a possibility that the forecasting method we used could contribute to the issuing of reliable near-field tsunami warning for M w 9 earthquakes.

Probabilistic Earthquake–Tsunami Multi-Hazard Analysis: Application to the Tohoku Region, Japan

“…The work can be extended using a Bayesian robust methodology (Cheung and Beck, 2010) to make more reliable estimations of earthquake-tsunami hazards. The proposed method can be further integrated into an operational tool for real-time earthquake-tsunami forecast (Tsushima et al, 2011) using data from offshore buoy and ocean-bottom pressure gauges. Furthermore, the methodology can be expanded to obtain the conditional tsunami or seismic hazard curve, given that a specific value of the counterpart hazard has been selected.…”

Simulation of distant tsunami propagation with a radial loading deformation effect

“…Tsunami propagation has been simulated by long-wave (non-dispersive) equations, and this approximation has been applied to model observed tsunamis especially in near fields (e.g., Aida, 1969;Satake, 1985;Tsushima et al, 2011). Recently, trans-oceanic tsunami simulations, with travel distances exceeding thousands of kilometers, have reported apparent travel time differences between simulations and observations.…”

Dispersion and nonlinear effects in the 2011 Tohoku‐Oki earthquake tsunami

“…Conversely, according to a tsunami waveform analysis, the tsunami forecasting by the DART system estimated the total tsunami energy within 1.5 h and successfully forecasted the tsunami arrivals and heights in the far-field coasts [Tang et al, 2012]. Numerous studies have been conducted to develop tsunami-forecasting techniques for near-field tsunami [e.g., Tsushima et al, 2011;Ohta et al, 2012;Gusman and Tanioka, 2013;Melgar and Bock, 2013;Wei et al, 2013].…”