The worst-class tropical cyclone-generated high waves identified by seismic noises

Abstract The extreme winds of tropical cyclones generate high waves over the ocean, causing severe damage to offshore facilities and coastal communities¹. Disaster mitigation requires accurate prediction and forecasting of the worst-class high waves. Furthermore, wave development, an entity of momentum loss from a tropical cyclone, determines the intensity of the tropical cyclone². However, the physics of wave development is not fully understood, and the number of mid-ocean observations during extreme tropical cyclones is extremely insufficient³. Therefore, physically and statistically evaluating worst-class high waves is difficult. However, ocean waves excite seismic noise (microseisms)⁴,⁵,⁶. Here, we utilize long-term microseisms observed by seismic observation networks⁷ to identify historical worst-class tropical cyclone-generated high-wave events around Japan. The identification is facilitated by using microseism energy within an 8–10 s period, and we show that Typhoon Wipha in 2013, Typhoon Lan in 2017, and Typhoon Hagibis in 2019 were the worst-class events in the past 20 years. Here, we show that microseism observations contain rich information on the development and propagation of waves depending on wave frequency, leading to a better understanding of the physics of high waves and accurate predictions of worst-class events.