A strong undersea earthquake has sent streams of people fleeing to higher ground in western Indonesia, after a tsunami warning was briefly triggered.
Footage released by the National Disaster Mitigation Agency showed how streams of people in a village on Mentawai Island fled to the highlands by foot and motorcycles under the rain in darkness early Tuesday, while some patients at the village's hospital were evacuated to its yard as cracks showed in the facility's floor.
The shocks were felt in districts and cities of West Sumatra and North Sumatra provinces, and some places ordered evacuations to higher ground.
Residents in parts of West Sumatra province, including the provincial capital of Padang, felt the earthquake strongly for about 30 seconds, disaster agency spokesperson Abdul Muhari said.
"Many residents in several villages on Mentawai island chose to stay ... in higher ground although the tsunami alert was ended, due to fears of aftershocks," he said, adding that authorities were still collecting information about the damage.
The magnitude 7.1 earthquake was centered 170 kilometres southeast of Teluk Dalam, a coastal town in the South Nias region of North Sumatra, at a depth of 15 kilometres, the US Geological Survey said. Aftershocks measured as strong as 5.8.
After an initial tsunami alert, Indonesia's Meteorology, Climatology and Geophysical Agency lifted the warning just before dawn, about two hours after the quake.
Authorities said that based on sea level observations, minor tsunamis of 11 centimeters were detected in Tanah Bala coastal area of South Nias regency.
Indonesia, a vast archipelago of 270 million people, is frequently struck by earthquakes, volcanic eruptions and tsunamis. In November, a magnitude 5.6 quake killed at least 340 people and damaged more than 62,600 homes in parts of West Java.