JAKARTA, Nov. 21 (Xinhua) -- An earthquake with magnitude of 5.5 rocked Sumatra Island on Wednesday morning, no report of damage or casualty, the Meteorology and Geophysics Agency said here.

    The quake jolted at 05:59 Jakarta time (2259 GMT, Tuesday) with epicenter at 165 kilometers southwest of Lais town of Bengkulu province and at 10 kilometers under sea bed, an official of the agency Indra Gyunawan told Xinhua.

    In September, 23 people were killed in the province and nearby province West Sumatra after a strong quake hit Bengkulu.

    In December 2004, over 170,000 people were killed in Aceh province in the northern tip of Sumatra island after a tsunami, triggered by a strong quake, devastated coastal areas of the province and other countries in Southeast Asia.

    Indonesia lies in a vulnerable quake-prone zone called "the Pacific Ring of Fire," where two continental plates meet and cause frequent seismic and volcanic movements.