Tokyo ? A powerful earthquake hit Tokyo and nearby areas shortly after dawn today, halting trains and forcing two nuclear reactors to shut down for safety checks. More than 30 people suffered minor injuries.

The U.S. Geological Survey said another, unrelated quake with a 7.6 magnitude hit the Indian Ocean about 160 miles north of Port Blair in India’s Andaman Islands. A tsunami watch was called for India, Myanmar, Indonesia, Thailand and Bangladesh. The caution was later lifted without any tsunami being recorded.

In Japan’s magnitude-6.5 temblor, at least 30 people were slightly hurt, the National Police Agency said. Public broadcaster NHK reported 43 were injured.

Japan’s Meteorological Agency also issued a tsunami warning, but that was later lifted. The quake was centered off Suruga Bay, southwest of Tokyo, at a depth of 12 miles.