The shocks were also felt in Makassar city and Selayar Islands district in South Sulawesi province, across the Flores Sea. The disaster mitigation agency reported a school was damaged in the Selayar Islands.
Muhari said that based on sea level observations, minor tsunami waves of 7cm (2.8 inches) were detected in Marapokot and Reo areas.
Dwikorita Karnawati, head of Indonesia’s Meteorology, Climatology, and Geophysical Agency, said people along the coastlines on the northern side of Flores should be aware of further quakes and a potential tsunami.
“The earlier earthquake no longer has a tsunami potential. But it is very possible there’ll be aftershocks, hopefully not stronger than before,” Karnawati said.
The chief of Flores Timur district, Anton Hayon, said no damage was reported.
“We asked people in the coastal areas to get away from the beach lines, especially in the northern side … as there was a big tsunami there back in 1972,” Hayon said.
He added that residents had joined a tsunami drill before and they know what to do.
Indonesia, a vast archipelago of 270 million people, is frequently struck by earthquakes, volcanic eruptions and tsunamis because of its location on the “Ring of Fire”, an arc of volcanoes and fault lines that arcs the Pacific.
The last major earthquake was in January, a magnitude 6.2 that killed at least 105 people and injured nearly 6,500 in West Sulawesi province.