# Looking for a scientific term that describes the 'convergence' of two or more tsunami systems **URL:** \ **Category:** Factual Questions\ **Created:** [June 1, 2021, 1:43pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350 "2021-06-01T13:43:50Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Octagon](https://avatars.discourse-cdn.com/v4/letter/o/2acd7d/32.png) [@Octagon](https://boards.straightdope.com/u/Octagon)\ **Post date:** [June 1, 2021, 1:43pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/1 "2021-06-01T13:43:50Z")
I’m for a scientific term that describes the ‘convergence’ of two or more tsunami systems. It’s not ‘convergent tsunami’. I haven’t found that term to describe the process of merging tsunami waves. I remember watching a video on the 2011 Fukushima tsunami. It was describing the ‘convergence’ of more than one tsunami system. The program used the word ‘convergent’ or ‘convergence’ but I could not find that term used anywhere to describe that process. I hope someone knows a proper scientific term to describe the actual ‘convergence’ of the tsunami waves as they merge and crash onto shore. The usual term for such a tsunami is ‘mega-tsunami’. ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [June 1, 2021, 2:09pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/2 "2021-06-01T14:09:22Z")
Are you talking about more than one seismic event occurring at the same time? That sounds unlikely, but perhaps waves rebounding off of two other land masses and meeting again at a third location is a possibility. I wonder if the word “convergent” in the show was referring to converging tectonic plates which was the cause of that tsunami. ---
**Author:** ![Frodo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frodo/32/302_2.png) [@Frodo](https://boards.straightdope.com/u/Frodo)\ **Post date:** [June 1, 2021, 2:10pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/3 "2021-06-01T14:10:50Z")
Constructive Interference? > **[Wave interference](https://en.wikipedia.org/wiki/Wave_interference)** > > Pages for logged out editors learn more > > In physics, interference is a phenomenon in which two waves combine by adding their displacement together at every single point in space and time, to form a resultant wave of greater, lower, or the same amplitude. Constructive and destructive interference result from the interaction of waves that are correlated or coherent with each other, either because they come from the same source or because they have the same or nearly the same frequency. Int... ---
**Author:** ![Octagon](https://avatars.discourse-cdn.com/v4/letter/o/2acd7d/32.png) [@Octagon](https://boards.straightdope.com/u/Octagon)\ **Post date:** [June 1, 2021, 2:33pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/4 "2021-06-01T14:33:52Z")
Thanks Elmer. I remember the animation of waves ‘converging’. I don’t remember it being in the context of the tectonic plates. Cannot waves caused by different tectonic disturbances converge at some point to create larger waves? I’m sorry I don’t have anything else to go on. ---
**Author:** ![Octagon](https://avatars.discourse-cdn.com/v4/letter/o/2acd7d/32.png) [@Octagon](https://boards.straightdope.com/u/Octagon)\ **Post date:** [June 1, 2021, 2:37pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/5 "2021-06-01T14:37:01Z")
Thanks Frodo. That’s exactly it. ---
**Author:** ![Elmer\_J.Fudd](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/elmer_j.fudd/32/1211_2.png) [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)\ **Post date:** [June 1, 2021, 2:43pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/6 "2021-06-01T14:43:11Z")
> [@Octagon](#): > > Cannot waves caused by different tectonic disturbances converge at some point to create larger waves? On average, there are only two tsunamis a year that actually cause any damage. The chances of two happening at the same time seems astronomically remote. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [June 1, 2021, 3:20pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/7 "2021-06-01T15:20:45Z")
I was going to suggest constructive interference, but was ninjaed by @Frodo . However Wikipedia lists other potential rogue wave mechanisms such as diffractive focusing, focusing by currents, nonlinear effects (modulational instability, solitons, etc), constructive interference, wind-wave interactions, and thermal expansion: > **[Rogue wave | Causes](https://en.wikipedia.org/wiki/Rogue_wave#Causes)** > > Because the phenomenon of rogue waves is still a matter of active research, stating clearly what the most common causes are or whether they vary from place to place is premature. The areas of highest predictable risk appear to be where a strong current runs counter to the primary direction of travel of the waves; the area near Cape Agulhas off the southern tip of Africa is one such area. The warm Agulhas Current runs to the southwest, while the dominant winds are westerlies, but since this thesi... ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [June 1, 2021, 3:32pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/8 "2021-06-01T15:32:37Z")
> [@Octagon](#): > > The usual term for such a tsunami is ‘mega-tsunami’. That’s not what a [megatsunami](https://en.wikipedia.org/wiki/Megatsunami) is. It’s when a large amount of material suddenly enters a body of water and causes a much higher wave than ordinary tsunamis. _Big_ stuff like asteroids or mountains. It’s not that multiple waves coalesce, it’s that the impulse is just that much bigger. ---
**Author:** ![Octagon](https://avatars.discourse-cdn.com/v4/letter/o/2acd7d/32.png) [@Octagon](https://boards.straightdope.com/u/Octagon)\ **Post date:** [June 1, 2021, 4:35pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/9 "2021-06-01T16:35:04Z")
> [@Octagon](#): > > Fukushima tsunami My mistake. Thanks for that correction. The Tōhoku earthquake was a teletsunami. ---
**Author:** ![Octagon](https://avatars.discourse-cdn.com/v4/letter/o/2acd7d/32.png) [@Octagon](https://boards.straightdope.com/u/Octagon)\ **Post date:** [June 1, 2021, 4:36pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/10 "2021-06-01T16:36:53Z")
Just for the record, the program I watched did not mention constructive interference or rogue waves. So thanks for the terminology. Would you apply these terms for any tsunami or the 2004/2011 variety ? ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [June 1, 2021, 5:05pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/11 "2021-06-01T17:05:00Z")
> [@Octagon](#): > > Would you apply these terms for any tsunami or the 2004/2011 variety ? No. Completely unrelated. ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [June 1, 2021, 6:18pm UTC](https://boards.straightdope.com/t/looking-for-a-scientific-term-that-describes-the-convergence-of-two-or-more-tsunami-systems/943350/12 "2021-06-01T18:18:11Z")
As @Darren_Garrison says, rogue waves, aka freak waves are not necessarily at all associated to impulsive tsunami or megatsunami displacements like earthquakes and rockfalls. But I was thinking that makes them even more mysterious and interesting, and appropriate, as test cases for constructive interference, non-linearity, and whatever other weird effects that can turn packets or groups of normal waves into a monster wave several times higher. E.g., this experiment > **[Laboratory recreation of the Draupner wave and the role of breaking in...](https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/laboratory-recreation-of-the-draupner-wave-and-the-role-of-breaking-in-crossing-seas/65EA3294DAFD97A50C8046140B45F759)** > > Laboratory recreation of the Draupner wave and the role of breaking in crossing seas - Volume 860 recreated a rogue wave as a result of “crossing seas” at a sufficiently large angle, so there is another scientific/nautical term for you.