<p>The reason why there was no large tsunami is due to the reason above, no significant uplift of the sea floor. </p>

<p>However, a small tsunami was produced. This was due to vertical features such as trenches and seamounts (basically, undulating bathymetry) moving laterally, in a strike-slip earthquake acting as paddles within the overlying water column. </p>

<p><a href="https://i.sstatic.net/HGsMm.jpg" rel="nofollow noreferrer"><img src="https://i.sstatic.net/HGsMm.jpg" alt="Graphic from Trinidad and Tobago Weather Center"></a></p>

<p>They have a pretty good overview of the situation here: <a href="https://www.facebook.com/notes/trinidad-and-tobago-weather-center/the-m76-great-swan-island-earthquake-tsunami/1693553420664701/" rel="nofollow noreferrer">The M7.6 Great Swan Island Earthquake &amp; Tsunami</a></p>

CC BY-SA 3.0
2018-02-12T01:30:39.587Z
2018-02-12T01:30:39.587Z
klh_geop
<p><a href="https://i.sstatic.net/BFLHq.png" rel="noreferrer"><img src="https://i.sstatic.net/BFLHq.png" alt="enter image description here"></a></p>

<p>This is the centroid moment tensor published by the USGS as of 01/10/18 (it will likely be updated in the future). As you can see this was an almost pure strike-slip mechanism on a near vertical plane.</p>

<p>Tsunamis are generated when the ocean floor is displaced upwards by an earthquake, displacing the water above it in the same pattern. This displaced water then spread out laterally to form the tsunami. Thrust faults tend to produce large seafloor uplifts and so most (maybe all?) tsunamis are associated with thrust faulting earthquakes.</p>

<p>There was no tsunami in this case because a strike slip fault like this does not produce a significant uplift of the seafloor. Instead the seafloor slides past each other.</p>

<p>With regard to the second part of the question; yes there have been tsunamis in the Caribbean before. <a href="http://poseidon.uprm.edu/lander/tabla1a.htm" rel="noreferrer">This website</a> provides a good list of known ones.</p>

CC BY-SA 3.0
2018-01-10T22:56:08.270Z
Tsunamis can also be generated by underwater landslides, which if I recall correctly are more commonly associated with continental outflows. That is, coastal sediment builds up offshore of a river outlet and a quake can cause the slope to collapse. (Land-side landslides, like avalanches in fjords, can also generate waves.)
jeffronicus
CC BY-SA 3.0
2018-01-10T21:17:56.033Z
2018-01-10T21:17:56.033Z
bon
<p>How come the strike-slip 7.6 M earthquake, occurring January 9th, 2018, produced no tsunami? Has there ever been any produced in this region?</p>

<earthquakes><seismology><tsunami>
2018 Swan Islands earthquake tsunami
Luke Hutton
# 2018 Swan Islands earthquake tsunami

(Asked by: username_0 on 2018-01-10)

How come the strike-slip 7.6 M earthquake, occurring January 9th, 2018, produced no tsunami? Has there ever been any produced in this region?

**Tags:** earthquakes, seismology, tsunami


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## 2 answers

### Answer by username_2 on 2018-01-10. Score: 8 | Accepted answer

[![enter image description here](https://i.sstatic.net/BFLHq.png)](https://i.sstatic.net/BFLHq.png)

This is the centroid moment tensor published by the USGS as of 01/10/18 (it will likely be updated in the future). As you can see this was an almost pure strike-slip mechanism on a near vertical plane.

Tsunamis are generated when the ocean floor is displaced upwards by an earthquake, displacing the water above it in the same pattern. This displaced water then spread out laterally to form the tsunami. Thrust faults tend to produce large seafloor uplifts and so most (maybe all?) tsunamis are associated with thrust faulting earthquakes.

There was no tsunami in this case because a strike slip fault like this does not produce a significant uplift of the seafloor. Instead the seafloor slides past each other.

With regard to the second part of the question; yes there have been tsunamis in the Caribbean before. [This website](http://poseidon.uprm.edu/lander/tabla1a.htm) provides a good list of known ones.

> **Comments:**
> **username_3**: Tsunamis can also be generated by underwater landslides, which if I recall correctly are more commonly associated with continental outflows. That is, coastal sediment builds up offshore of a river outlet and a quake can cause the slope to collapse. (Land-side landslides, like avalanches in fjords, can also generate waves.)  

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### Answer by username_1 on 2018-02-12. Score: 2

The reason why there was no large tsunami is due to the reason above, no significant uplift of the sea floor.

However, a small tsunami was produced. This was due to vertical features such as trenches and seamounts (basically, undulating bathymetry) moving laterally, in a strike-slip earthquake acting as paddles within the overlying water column.

[![Graphic from Trinidad and Tobago Weather Center](https://i.sstatic.net/HGsMm.jpg)](https://i.sstatic.net/HGsMm.jpg)

They have a pretty good overview of the situation here: [The M7.6 Great Swan Island Earthquake & Tsunami](https://www.facebook.com/notes/trinidad-and-tobago-weather-center/the-m76-great-swan-island-earthquake-tsunami/1693553420664701/)


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