Coastal Engineering Professor Creates Models of January 2021 Trans-Pacific Tsunami

January 15, 2022
2022 Tonga Volcano Tsunami

January 15, 2022's trans-Pacific tsunami was generated by the Tonga Volcano eruption on the western side of the Pacific Ocean. Read SDSU Coastal Engineering professor Ignacio Sepúlveda's write-up regarding the event below, and watch preliminary models of the effects of the tsunami in Southern California here.

The Trans-Pacific tsunami of January 15, 2022 was generated by the Tonga Volcano eruption in the western side of the great Pacific Ocean. The tsunami was generated by a big explosion that occurred at 4:30 UTC time. The tsunami genesis and propagation from yesterday is special in many ways.

1) It is the first time we are fully recording a Trans-Pacific tsunami originated by a volcano and not by a big earthquake. This set new challenges for scientists, hazard assessments and warning systems:
- How do we estimate the rate of eruption recurrence of every great volcano?
- What are the key geometric properties and uncertainties of the tsunamigenic mechanism?
- Will the tsunami-related waves resonate with bays?

2) The wavelength (i.e. horizontal length) of tsunami waves are smaller than that of tsunamis generated by big subduction earthquakes. It seems to me this is the reason why we saw surprising amplitude amplifications of tsunami waves in some bays and coastal areas. For example, we saw important amplifications in Los Angeles (United States) and Coquimbo (Chile), while in other places like San Diego, the tsunami was small. Tsunami waves also had a very slow decay (of many hours) in some bays. Certainly, we have a lot to learn about this very special event. Here I prepared a preliminary model calibrated with nearby tide gauge stations. For comparison, view my other simulations for the 1960, 1964, 2011 and 2010 here.

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