"If I stay at a shelter, who will care for my animals?" said Adi Wiyono, 45. "I am afraid, but they are the source of my life, my family depends on them."
Supriyatun, 30, agreed, saying she had no choice but to go back.
"I must milk my goats and sell it to survive," she said.
Indonesia's most dangerous mountain has been venting steam and debris for more than a month, and on Thursday spit billowing gray clouds of hot ash 3 1/2 miles down the slope, the largest burst yet.
The volcano appeared calmer Friday, though a local monitoring station tallied 63 lava bursts and nine small gas emissions. Ash continued to rain on villages, covering crops and rooftops in a thin layer of gray soot, the official Antara news agency reported.
Merapi's lava dome has swelled, raising concerns that it could suddenly collapse and send scalding clouds of fast-moving gas, rocks and debris into still-populated areas. Hundreds of aftershocks, including a 3.5-magnitude temblor Friday, added to those worries.
"The trend seems to be that the volcanic activity is increasing," said Dr. Antonius Ratdomopurbo, an Indonesian volcanologist who monitors the peak. He added, though, there "is no reason for people to be overly concerned" at present.
Some scientists say a massive May 27 earthquake that killed more than 5,700 people in an area 25 miles south of Merapi may have contributed to the restive mountain's volatility in recent weeks.