"Tremors have not stopped rocking this area since yesterday," Hamdani, an officer in charge of the volcano monitoring post in the village of Hargopancuran, South Lampung, said here Tuesday.
The peak was not visible as it was blanketed with black clouds on Tuesday morning, Hamdani said.
The tremors, however, were less intense than yesterday when the volcano spewed hot lava and other volcanic materials as high as 600 meters from its peak.
"But it is difficult to predict Anak Krakatau," Hamdani said.
The meteorology and geophysics office warned fishermen to stay away from the volcano although it said the tremor would not cause tsunami.
Krakatau`s explosion in the 18th century caused one of the most devastating tsunamis in history in the world.
The sound of the explosion was heard as far away as Australia 3500 km away, and the island of Rodrigues near Mauritius 4800 km away. It is the loudest-ever sound in recorded history.