Tsunami effects smaller than expected. Experts praise the warning system

Yesterday’s earthquake in Russia triggered mass evacuations and widespread panic across the Pacific region. However, observations indicate that the tsunami effects, which echoes are still being felt today, are significantly smaller than initially predicted. Geologists explain the forecasting error.

The great quake, even greater fears

Late Wednesday morning, an earthquake measuring 8.8 on the Richter scale struck Russia’s eastern coast on the Kamchatka Peninsula. It was the sixth strongest earthquake in the history of seismological records. Unsurprisingly, the world – mindful of the 2011 disaster – mobilized quickly, anticipating the arrival of a massive tsunami. Concerns intensified after the eruption of the Klyuchevskoy volcano in Kamchatka, which followed the tectonic tremors.

Global seismological agencies immediately issued a series of warnings for the Pacific region, stretching as far as Chile and French Polynesia. In eastern Japan and on islands belonging to Ecuador and Chile (including Easter Island and the Galápagos), authorities ordered evacuations from coastal zones. Tourists and residents in Hawaii were advised to move to higher ground as quickly as possible – many spent the night in cars parked on nearby hills. In Honolulu, widespread panic caused traffic gridlock on roads and highways.

Surprisingly mild tsunami effects

According to experts from the U.S. Tsunami Warning Center, waves reaching up to 174 cm hit Hawaii before noon yesterday. All flights to the island of Maui were preemptively canceled. In California, the highest recorded tsunami amplitude was estimated at 120 cm, but no serious damage was reported. Residents are still advised to remain cautious and to avoid entering the ocean or sailing.

On Wednesday afternoon, the tsunami warning was downgraded for both Japan and Hawaii. In Japan, the water level rose only 130 cm. Waves reaching the Marquesas Islands, part of French Polynesia, also turned out to be much smaller than forecasted. International experts believe the worst has passed but still urge caution, noting that the effects of the earthquake may be delayed due to the vast distances involved. Strong ocean currents expected today could pose a danger to swimmers and fishermen.

The Kuril Islands experienced the strongest tsunami impact, with waves reported by the Russian news agency RIA to have reached heights of 3–5 meters. Fortunately, there were no casualties or damage to residential homes, although the water flooded the waterfront, causing damage to port infrastructure and vehicle fleets.

Where does the discrepancy come from? Experts explain

It’s worth recalling that the 2011 earthquake, with a magnitude of 9.1, led to drastically different consequences. In Japan, the tsunami resulted in a major nuclear disaster at the Fukushima plant and nearly 20,000 fatalities. The highest waves at the time reached 9–12 meters.

How is it possible that the Kamchatka earthquake had such mild effects? Prof. Lisa McNeill of the University of Southampton explained in an interview with the BBC that tsunami impacts largely depend on the shape of the ocean floor and the depth of the hypocenter, the quake’s point of origin. Yesterday’s quake, according to preliminary US Geological Survey data, was located about 20 km below the Earth’s surface and initially suggested the potential for very high waves.

According to Dr. Stephen Hicks from University College London, it appears that the initial estimates were overly conservative. If the hypocenter was actually deeper, the tsunami waves would not have been able to reach the projected amplitude.

The effectiveness of the international early warning system deserves particular attention. During the dramatic 2004 tsunami, which killed 230,000 people across 14 countries, the lack of rapid alerts was a major failing. It’s clear that a false alarm is far better than no warning at all.

The Russian Geological Research Institute has announced that it will closely monitor the tectonic situation in the Kamchatka region. Aftershocks are expected in the coming month.