JAKARTA, Sept. 17 (Xinhua) -- The 7.9-magnitude earthquake in Bengkulu province of Sumatra Island last week has triggered the rise of seismic activities of three volcanoes in the area, but they all still calm now, the Indonesian Volcanology and Mitigation Center said on Monday.

    The quake with the epicenter located in western waters off Sumatra Island was followed by a string of tremors with magnitudes ranging from four to more than seven. Scores of tsunami warning were issued.

    "The three mountains, Dempo, Kaba and Talang, have greater seismic activities after the quake," the head of volcanological survey of the center, Yan Saut Simatupang, told Xinhua.

    Simatupang said that Mount. Talang located some 30 kilometers from Padang, the capital of West Sumata province, may spew white cloud along with volcanic ashes, but Mount. Dempo and Kaba in Bengkulu province may not, as both of them have rarely spewed lava, he said.

    "There is a possibility that the Mount. Talang releases white cloud containing ashes," said Simatupang.

    "There will be blows of energy but they will not be significant, nothing to be worried," he said.

    West Sumata is one of the second worst-hit provinces after Bengkulu province.

    Nineteen people were killed in Bengkulu and four others in West Sumatra. Eighty-eight people were injured in the two provinces.

    Mount. Talang, Dempo and Kaba are parts of the country's 129 active volcanoes, 66 of which are located in high-density population areas, Java and Sumatra islands, according to the meteorology agency.

    Indonesia lies at a vulnerable zone called "the Pacific Ring of Fire" where two continental plates meet, causing frequent volcanic movements.