Scientists from NOAA’s Great Lakes Environment Research Laboratory have shown that tsunamis can cause not only seismic shocks, but also gravitational waves. Essentially, meteotsunami are triggered by waves of air over water. The research is published in the journal Natural Hazards.
On April 13, 2018, a huge wave suddenly appeared on the eastern shore of Lake Michigan. At the same time, there was not a single fault line next to the emerging natural phenomenon, usually associated with huge waves. Scientists have figured out the mechanisms behind the appearance of such waves.
“We found that we can probably predict at least a specific subset of meteotsunami that are caused by large-amplitude atmospheric gravity waves,” said Eric Anderson, NOAA lab oceanographer and lead author of the paper.
Meteotsunami occur in the Great Lakes, the Gulf of Mexico, and the Mediterranean Sea. Anderson said that meteotsunami is easier to predict than normal thunderstorms, since there is only one key variable involved: atmospheric pressure, or rather, dramatic changes in it. A tsunami occurs when a sudden, abrupt change in air pressure hits water, moving it towards the shore like a rolling pin pushing dough.
When the air moves faster or slower than the water into which it enters, there is no danger – the wave dries up, and it does not have enough thrust to continue moving.
Climate change could exacerbate this phenomenon. Meteotsunami have been found on all continents except Antarctica, and a recent meeting of meteotsunami experts in Croatia laid the foundation for a better understanding of these unique phenomena in a global context.
“With current climate projections, the intensity of meteotsunami is unlikely to change, but the frequency, at least in summer, is likely to increase significantly,” Anderson said. More convective weather conditions in late spring and early summer are more likely to catalyze such wave phenomena. According to scientists, meteotsunami are no less dangerous for people than storms. Since they cause injuries to those who spend time on the beach or on small boats.