Evaluation of potential hazards from teletsunami in China: Tidal observations of a teletsunami generated by the Chile 8.8 M w earthquake

Abstract

an earthquake of M w 8.8 rocked the central coast of Chile. A teletsunami was triggered by the huge earthquake and then propagated across the entire Pacific in less than 24 h. The initial tsunami wave arrived at the southeast coast of China at 16 : 20 on February 28 and was recorded in real time by a number of tidal gauges off mainland China and Taiwan Province. The teletsunami waves have never been recorded with such a broad geographical scope in China before this event. The aim of the present work is to report the first description of sea-level oscillations generated by the Chile tsunami, and evaluate the potential hazards that teletsunami poses to the coast of China. The results reveal that the east coast of Taiwan Province, Zhejiang Province and the north coast of Fujian Province are vulnerable to transoceanic tsunami. In addition, spectral and wavelet analysis of the recorded sea-level oscillations shows that "seiches" are easily excited by the resonance resulting from the interaction between the initial tsunami waves and local geometry (such as semi-enclosed bays and ports). The superimposition of the two oscillations would amplify the wave height further.Chile, teletsunami, wave height, seiche, potential hazard Citation:Yu F J, Yuan Y, Zhao L D, et al. Evaluation of potential hazards from teletsunami in China: Tidal observations of a teletsunami generated by the Chile 8.8 M w earthquake.

Records of the tsunami induced by the 2010 Chilean earthquake from Xiaoqushan seafloor observatory in the East China Sea

“…Therefore, the exact sea-level anomaly induced by the Chilean tsunami is difficult to calculate. Yu et al [9] found that the sea-level anomaly induced by the Chilean tsunami near Xiaoqushan Island was around 0.1 m, which differs from the value of 0.48 m determined in this paper. The difference is understandable in that the different measurements were obtained at different locations with different topography and analyzed using different methods.…”

“…This suggests that a tsunami with periods of 50-150 min contributed largely to the local sea-level anomaly around Xiaoqushan Island. This result is consistent with the result of Yu et al [9] that the Chilean tsunami propagating into the East China Sea had periods of 35-100 min. The large values in the spectrum at low frequencies are probably due to background signals, such as signals of surges or wind waves propagating from other seas, not being filtered out.…”

“…It was usually accepted that there are seldom tsunamis in marginal seas owing to the shallow and broad continental shelf [4], and this seems to be true in the past for China according to limited documentary records [5][6][7][8][9]. However, this view has been called into serious question after the tremendous tsunami disaster resulting from the Indonesian earthquake on December 26, 2004, in which the death toll was more than 230000 and numerous coastal towns were destroyed [10].…”

“…As a result, improving the tsunami warning system is crucial. Scientists in China have recently undertaken the task to develop a tsunami propagation model [6,7], and the State Ocean Administration of the People's Republic of China has set about to construct a tsunami warning system offshore [9]. In this paper, sea-level data obtained from the Xiaoqushan seafloor observatory and sea surface temperature, salinity and wind obtained from a nearby weather station are analyzed to obtain residual sea-level anomalies by extracting tidal and wind-induced components.…”

Coastal seafloor observatory at Xiaoqushan in the East China Sea

“…The real-time series of sea level data obtained from CTD at Xiaoqushan Seafloor Observatory is used to learn how tsunami in remote regions may impact the coastal processes off the ECS. The tsunami, for example, induced by the 2010 Chile earthquake occurred off the coast of the Maule Region of Chile at 14:43 on Feb. 27 in 2010 (Beijing time, the first green pentagram labeled in Figure 6b) rating a magnitude of 8.8 on the moment magnitude scale, affected most of the Pacific ocean region [12,13]. According to the seismic wave propagation, P-wave and S-wave arrived at Xiaoqushan Seafloor Observatory 20 and 27 h later, respectively.…”