Submarine Earthquakes

The Earth's surface or lithosphere comprises tectonic plates which average approximately 50 miles in thickness, and are continuously moving very slowly upon a bed of magma in the asthenosphere and inner mantle. The plates converge upon one another, and one subducts below the other, or, where there is only shear stress, move horizontally past each other. Little movements called fault creep are minor and not measurable. The plates meet with each other, and if rough spots cause the movement to stop at the edges, the motion of the plates continue. When the rough spots can no longer hold, the sudden release of the built-up motion releases, and the sudden movement under the sea floor causes a submarine earthquake.
Submarine Earthquakes are not uncommon in the City of Aogua and the adjacent Blacksites. They are one of the reasons why Syreni build their homes and buildings out of soft and yielding material like mesoglea and they stay connected to the ground through different kind of cords, also often made out of mesoglea, or tang or coral reefs.
On Blacksites though, Syreni don't often have the luxury of creating their own buildings and instead make homes in coral reefs. These are more easily disturbed by earthquakes but like the city buildings, are yielding and they usually survive this natural disaster.
In that way, submarine Earthquakes don't cause a lot of damage amongst Syreni. One exception for that would be Syreni affected by Blackness, which are often driven away from their homes in coral reefs and find shelter in small cave like structures. Blacksite #2369 Cavesystem is especially threatened by this as it has lost a lot of its integrity after decades of Syreni working on it, caving out their own paths and alterating it to their own needs. This has led to some rooms in the cavesystem to already have collapsed and if the locals are to be believed, another big earthquake is on its way and it will eradicate the Blacksite #2369 Cavesystem and all its inhabitants.

Type

Natural