The U.S. Geological Survey determined the quake was centered 110 miles (175 km) west-southwest of the Java city of Malang, or 360 miles (575 km) east-southeast of the capital, Jakarta.
Indonesian government geologist Setiono said the shallow quake was felt only moderately in several towns of Central Java.
Indonesia sits on the so-called Pacific Ring of Fire, and is often struck by strong tremors and regular volcanic eruptions.
The country was the worst nation hit by the December 2004 quake and tsunami that killed 168,000 people in northwest Sumatra’s Aceh province.
