One of the reasons for this earthquake is that Sichuan is located near the Himalayan seismic belt, which is one of the most active areas of orogeny in the world, and Wenchuan itself is located on the fault zone, so it is not surprising that an earthquake occurred.

As you said, 30 degrees north latitude is a mysterious place, where there are always all kinds of magical events. In fact, 30 degrees south latitude is equally mysterious, such as the Great Barrier Reef and Ayers Boulder in Australia, which are rarely found because most of the land is distributed in the northern hemisphere.

These problems themselves are unsolved mysteries, and it is too persistent to say that they have something to do with this earthquake.