I dunno were the article is but im going to try my best
ANSWER:
When the tectonic plates at transform boundaries slide past one another in opposite directions.
Jagged edges of the plates might get stuck together, causing pressure and tension to build up in the Earth's surface, then an earthquake happens when the plates move again.
This is due to warmer climates that are closer to the equator and therefore having a higher likely hood of there being more swamps closer to the equator.
