It took about eight minutes for the quake to reach Taiwan, an island of 23 million people about 1,200 miles (1,900 kilometers) from the quake's epicenter in China's Sichuan Province, Taiwan's Central Weather Bureau said.
Earthquakes frequently rattle Taiwan, which is located between the Eurasia and Philippine plates. Most are minor and cause little or no damage.
Sichuan does not sit along the edge of a plate, however, and it could have taken 100 years or more to accumulate enough energy to trigger such a large quake, said Taiwanese meteorologist Hsiao Nei-chi.
A magnitude 7.3 earthquake in central Taiwan killed more than 2,300 people in September 1999, Hsiao said.
A magnitude 7.8 earthquake is considered a major geological event that is capable of causing widespread damage and injuries in populated areas.