Key Takeaways:
- A meteotsunami is a series of long waves caused by sudden changes in air pressure from fast-moving weather systems, like thunderstorms.
- The key to a meteotsunami is timing, when the speed of the pressure disturbance matches the speed of the wave in the water.
- Meteotsunamis can grow bigger if the coastline has features like a shallow shelf, a bay, or an inlet.
- Tsunamis can be triggered by earthquakes, weather, underwater landslides, or volcanic eruptions.
- Even small tsunamis can pose serious risks to people in the water or on boats.
Introduction to Meteotsunamis
A meteotsunami, short for meteorological tsunami, is a series of long waves caused by sudden changes in air pressure from fast-moving weather systems, like thunderstorms. These pressure changes push on the ocean surface, creating waves that travel toward the shore. According to GeoNet, if the coastline has features like a shallow shelf, a bay, or an inlet, the waves can grow even bigger. This phenomenon is similar to a traditional tsunami, but instead of being caused by an earthquake, it is triggered by changes in air pressure.
The Science Behind Meteotsunamis
The key to a meteotsunami is timing; when the speed of the pressure disturbance matches the speed of the wave in the water, which depends on how deep the water is, the wave’s energy builds up rapidly. This can make the waves much larger than usual, even without an earthquake. The speed of the pressure disturbance is crucial, as it determines whether the wave will amplify or dissipate. When the conditions are right, a meteotsunami can produce waves that are much higher than usual, posing a significant threat to coastal communities.
Recent Meteotsunami Event in New Zealand
From the afternoon of Tuesday, December 2, to Wednesday, December 3, Earth Sciences’ weather team had seen waves of active thunderstorms moving across the upper North Island. According to Earth Sciences New Zealand forecasting and media principal scientist Chris Brandolino, it’s almost certain that the minor tsunami activity detected nearby is related to these thunderstorms. GeoNet instruments at Napier, Castlepoint, Gisborne, and Lake Taupō, part of its tsunami gauge network, picked up these waves. The largest observed wave was 25cm in Napier, which may not seem significant, but it’s essential to understand that even small tsunamis can pose serious risks to people in the water or on boats.
Detecting Tsunamis
To detect a tsunami, GeoNet looks at de-tided data. This means it takes the original sea-level measurements and removes the regular tidal patterns scientists expect. What’s left shows other changes, like storm surges, tsunami waves, or gradual shifts in sea level. By analyzing this data, GeoNet can identify tsunami activity and provide early warnings to coastal communities. Tsunamis aren’t just triggered by earthquakes or weather; they can also be caused by underwater landslides or volcanic eruptions. Understanding the causes and characteristics of tsunamis is crucial for developing effective warning systems and mitigating the risks associated with these events.
Understanding Tsunami Behavior
When people hear the word tsunami, they often imagine towering waves crashing onto shorelines. However, according to GeoNet, tsunamis behave more like fast-flowing tides than regular ocean waves, carrying water and debris in and offshore and generating strong currents as they do so. While a small tsunami is unlikely to sweep over people and structures, it still poses serious risks to people in the water or on boats. The strong currents and debris carried by the tsunami can cause significant damage and loss of life, even if the wave itself is not extremely high.
Conclusion and Importance of Preparedness
GeoNet said the recent meteotsunami event was a good reminder that tsunamis do happen in New Zealand, and it’s always essential to be prepared. Even small tsunamis can pose significant risks to people in the water or on boats, and understanding the causes and characteristics of these events is crucial for developing effective warning systems and mitigating the risks associated with them. By staying informed and being prepared, coastal communities can reduce the impact of tsunamis and stay safe during these events. It’s essential to remember that tsunamis can be triggered by various factors, including earthquakes, weather, underwater landslides, and volcanic eruptions, and being aware of these risks is the first step towards preparedness.