Wikipedia:Reference desk/Archives/Science/2025 August 1

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August 1

Tsunamis on the "wrong" side of a landmass

I've just read about the Port of Honolulu ordering watercraft to weigh anchor ahead of an anticipated tsunami from the recent Russian earthquake (example story), even though the earthquake was north of Hawaii and the port is on the southern side of Oahu. I also remember the Effect of the 2004 Indian Ocean earthquake on India including damage on the country's west coast, even though the earthquake was east of the country.

In general, how can this happen? All I can think of is curving or bouncing off one landform, but it doesn't make sense to me how they could curve, and I'd expect them to spend their energy in the process of crashing into a coastline. Nyttend (talk) 20:26, 1 August 2025 (UTC)[reply]

In this animated simulation of the 2004 Indian Ocean earthquake and tsunami, you can see the front of the tsunami encitcle Sri Lanka. Fluid dynamics is rather different from the dynamics of shot launched from a gun.  ​‑‑Lambiam 20:53, 1 August 2025 (UTC)[reply]

Waves – tsunamis, sound waves, radio waves etc. – can curve. The physics term is diffraction. If the wavelength is long compared to the size of the obstacle, the waves can easily hit the back side of it. Like how you can hear cars pass when you stand against the back of a noise barrier. PiusImpavidus (talk) 23:41, 1 August 2025 (UTC)[reply]

I heard a TV newsreader say that the earthquake and tsunami have caused widespread fear in three continents - Asia, the Americas, and Europe. Unless they think that far-Eastern Russia is part of Europe, I don't know what Europe has to be concerned about. -- Jack of Oz ^{[pleasantries]} 03:07, 2 August 2025 (UTC)[reply]

Maybe if it runs through the Arctic region? ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:12, 2 August 2025 (UTC)[reply]

Relatives and friends in Europe of people living in (or visiting) threatened areas will have feared for their well-being. There may also have been some in Europe without such direct connections who remembered watching helplessly, in horror, as the 2004 Boxing Day disaster unfolded, and feared a replay.  ​‑‑Lambiam 06:30, 2 August 2025 (UTC)[reply]

It was a big news item in Europe, for a few hours, but talking about "widespread fear" is exaggerated. Fear must have been more widespread in Oceania. PiusImpavidus (talk) 08:19, 2 August 2025 (UTC)[reply]

But not anywhere in Australia, despite a common Facebook meme claiming the opposite. HiLo48 (talk) 06:11, 3 August 2025 (UTC)[reply]

Or even in Vanuatu Greglocock (talk) 06:34, 3 August 2025 (UTC)[reply]