Earthquakes are a common cause of tsunamis, but the weather can also be a culprit when it comes to creating large waves. Scientists have now analyzed the first meteotsunami—a portmanteau of “meteorological tsunami”—to hit the Persian Gulf. This event, which occurred in 2017, is troubling, the research team suggests, because so much infrastructure, including high-end resorts and oil- and gas-related equipment, dots the shoreline of this part of the Middle East.
Mohammad Heidarzadeh, a coastal engineer at Brunel University London, and his colleagues first learned about the 19 March 2017 meteotsunami through Iranian media outlets. “When we heard the news…it was a shock,” said Heidarzadeh.
Seismic activity in the Persian Gulf isn’t strong enough to generate traditional tsunamis, and a meteotsunami had never before been reported in the area. The event, which occurred at roughly 8:00 a.m. local time, killed five people, sank fishing boats, and sent water rushing about a kilometer inland.
Heidarzadeh and his collaborators have now used sea level data and air pressure records to analyze the waves and the weather conditions that created them. Using measurements from 12 tide gauges in the Persian Gulf, Heidarzadeh and his team found that waves as large as 2 meters from crest to trough—roughly 5–10 times larger than normal—rolled ashore in southern Iran. Unlike regular waves, which arrive every 10 seconds or so, the meteotsunami waves arrived every 15–20 minutes, the scientists calculated. The turbulent seas were remarkably localized, however, and affected only a roughly 40-kilometer section of coastline near the city of Dayyer.
Air pressure records from across the Middle East and satellite observations revealed the meteorological conditions that preceded the meteotsunami. Heidarzadeh and his colleagues found that a tropical cyclone had passed over the region shortly before the first waves were recorded. Such convective storms are characterized by updrafts and downdrafts, which trigger changes in air pressure that can cause meteotsunamis. “Atmospheric conditions over the [Persian Gulf] were highly favourable for the generation of meteotsunamis,” the researchers concluded. Their study was published earlier this month in Pure and Applied Geophysics.
“This certainly looks like a classic meteotsunami event and an extremely large one at that,” said Gregory Dusek, a physical oceanographer at the National Oceanic and Atmospheric Administration’s National Ocean Service in Silver Spring, Md., not involved in the study. “It would be valuable to collect a longer time series of water level observations to assess just how rare this type of event is in the Persian Gulf.”
There’s hope for predicting meteotsunamis in the Persian Gulf, Heidarzadeh and his collaborators suggest. Because weather systems tend to move from west to east, meteorological stations to the west of the inland sea—in Kuwait, Saudi Arabia, Bahrain, and Qatar, for instance—can be used to track conditions conducive to a meteotsunami. That’s good news because roughly a third of the world’s oil transported over water passes through this region, and waves that destroy critical infrastructure could spell “a disaster for the world’s energy supply,” said Heidarzadeh.
Heidarzadeh and his colleagues are now creating computer animations of the 2017 meteotsunami. They’re using these simulations to study how the waves propagated across the Persian Gulf, work that informs how meteotsunamis travel in shallow, protected bodies of the water. “We really have to work on the full reconstruction,” said Heidarzadeh.
—Katherine Kornei (@katherinekornei), Freelance Science Journalist