Why do submarine earthquakes occur around the Cayman Trench?

Submarine earthquakes occur around the Cayman Trench primarily due to the complex tectonic activity along the margins of the Caribbean Plate.

The geological history of the region involves the movement of the Caribbean floor, which originated as a submarine plateau in the Pacific basin before penetrating the gap between the North and South American plates. As this plateau moved, the northern and southern margins of the Caribbean were subjected to significant shearing and dismemberment. This process of tectonic reorganization, particularly the shearing of the region's margins, creates the instability that leads to seismic activity.123

While the trench itself is a deep trough formed by these tectonic shifts, the earthquakes are specifically associated with the edges of the trench, where the crustal plates continue to interact and shift against one another.2