A magnitude 6.1 earthquake shook Indonesia\'s Sulawesi Island Tuesday, the U.S. Geological Survey said. The USGS said its monitors placed the epicenter of the quake 99 miles deep and about 43 miles south of Gorontalo, 231 miles east-northeast of Palu and 612 miles north-northwest of Dili in East Timor. No tsunami warning was issued, officials said.