(Corrects spelling in paragraph 6 to Subandi, not Sabandi)
SIKKA, Indonesia, Aug 16 (Reuters) - Around 5,000 people have been evacuated after a magnitude-7.7 earthquake smashed an area in eastern Indonesia, killing at least 51, blocking roads and causing landslides, authorities said on Sunday.
Thirty-six people were seriously injured in the Saturday morning quake in East Nusa Tenggara province, while 77 had minor injuries, Deputy Health Minister Benjamin Paulus Octavianus told a televised meeting.
The quake, followed by some 341 aftershocks, is the Southeast Asian nation's worst in years. Hundreds died after a 2022 earthquake in West Java.
More than 3,300 people in the Sikka region self-evacuated or were stranded in a sports arena, said the disaster mitigation agency BNPB.
Some Sikka residents were stranded outside collapsed homes under a makeshift tent made out of tarp, while some people received treatment in a tent outside a hospital in the port town of Maumere.
"Almost all of Sikka's residents didn't dare stay indoors, so they slept on a porch or a tent outside," Simon Subandi, deputy regent of Sikka, told news channel KompasTV.
More than 3,500 military and police officers have been deployed to the region, Cabinet Secretary Teddy Indra Wijaya said in a statement.
Rescuers were able to access parts of Maumere that had been blocked by landslides, Indonesia's search and rescue agency said. Most of those missing were trapped under rubble, and more than 1,300 homes were damaged, BNPB said.
Twenty petrol stations were not operational due to power outages, said state energy firm Pertamina.
The East Nusa Tenggara government is considering declaring an emergency for the province, BNPB said, which would allow authorities to mobilise resources and funding.
The area of the quake was hit in 1992 by a magnitude-7.5 earthquake that caused extensive destruction, Indonesia's geophysics agency said.
Indonesia, a sprawling archipelago of 290 million people, straddles the "Pacific Ring of Fire", a seismically active zone where tectonic plates meet, triggering frequent earthquakes and volcanic eruptions.
(Reporting by Arnold Welianto in Sikka and Stanley Widianto in Jakarta; Editing by William Mallard)
