An earthquake measuring 6.6 magnitude on the Richter scale jolted Aceh province in northern tip of Indonesia's Sumatra island on Saturday, the Meteorology and Geophysics Agency reported. The USGS reported the quake was at 5.9 magnitude. The quake's epicenter was at 24 km northwest Kota Subulus Alam of Aceh province with a depth of 103 km under the earth, an official of the agency told Chinese news agency (Xinhua). The intensity of the quake was felt at 4 MMI (Modified Mercally Intensity) in Blang Pidie and Sibolga and 2 MMI in Sibolga and 3 MMI in Banda Aceh, he said. "No reports of damage or casualty are received so far, as the center of the quake was deep," the official said Indonesia sits on a vulnerable quake-prone zone called "the Pacific Ring of Fire".