The national disaster management agency (BNPB) raised the death toll from 40 late Saturday, and rescue official Fathur Rahman said 50 people were injured in the 7.7-magnitude quake.
Suharyanto, the head of Indonesia's national disaster mitigation agency, said earlier that people were trapped in several buildings.
"These will be the initial targets of the disaster response teams," said Suharyanto, who, like many Indonesians, uses one name.
Two helicopters and a plane were being readied to assist in rescue operations.
European Union chief Ursula von der Leyen offered help from the bloc's Copernicus Earth observation satellites.
