Seismic signal detected before Tonga eruption could help with tsunami warnings
A seismic wave detected shortly before the Hunga Tonga-Hunga Ha’apai eruption in January 2022 could help scientists predict future volcanic activity in remote ocean regions. A study published by the American Geophysical Union suggests that the seismic wave, which was detected 750 kilometers from the volcano, was likely caused by a break in the oceanic crust. This rupture allowed seawater to interact with magma near the volcano’s magma chamber, leading to the eruption. The research provides insight into early eruption indicators, which could be crucial for tsunami warning systems.
Precursor signals can improve tsunami warnings
According to the study published15 minutes before the January 15 eruption, a Rayleigh wave was recorded at two remote seismic stations in Fiji and Futuna. It sparked interest among researchers studying volcanic triggers. According to University of Tokyo volcanologist Mie Ichihara, the seismic activity likely indicated a significant fracture in the crust beneath the caldera. This allowed seawater and magma to mix, causing a violent eruption. The event underlines the need for effective early warning mechanisms for island states vulnerable to volcanic eruptions and the tsunamis they can cause.
Seismic activity analysis for predictive insights
Takuro Horiuchi, lead author of the study and a graduate researcher in volcanology at the University of Tokyo, notes that seismic waves often accompany volcanic eruptions, but these signals are typically subtle and limited to the immediate vicinity of the volcano. However, this particular seismic wave traveled hundreds of kilometers, indicating a major geological event prior to the eruption. Horiuchi and Ichihara believe the rifting process may have caused extensive movements in the crust, ultimately leading to the explosive eruption.
Learning from rare caldera-forming eruptions
The Hunga Tonga-Hunga Ha’apai eruption was unusual because of its underwater location and the enormous energy released. Ichihara points out that understanding the mechanisms behind such events is challenging because there are few documented cases of caldera-forming eruptions, especially in oceanic environments. The seismic wave that precedes the eruption presents a possible sequence of events, although Ichihara warns that in other cases other processes may be involved.
Future application in disaster preparedness
Ichihara suggests that detecting seismic signals from volcanic eruptions could buy local observatories valuable preparation time. If future eruptions produce similar seismic signals, tsunami-prone areas may have more time to respond, providing a significant benefit to disaster preparedness in vulnerable areas.
