GOMA, Democratic Republic of Congo—An earthquake measuring a magnitude 5.3 rocked the borderlands between Rwanda and Congo on Tuesday morning, the Rwandan Seismic Monitor said, raising worries about a fresh eruption following one on Saturday that killed at least 32 people. On Saturday Democratic Republic of Congo’s Mount Nyiragongo, one of the world’s most active and dangerous volcanoes, erupted sending a river of lava downhill towards Goma, a city of some two million people. The area has experienced repeated tremors since then, and the lava lake in the volcano’s crater appears to have refilled, raising fears of new fissures or another eruption, the United Nations Refugee agency said. The earthquake appeared to have collapsed several buildings in Goma, a Reuters reporter said, although it was not yet clear if there were any casualties as police had sealed off the area. The quake struck at 11:03 a.m. local time originating in …