Mount Kelud, which sits on the densely populated island of Java, about 385 miles east of the capital, Jakarta, last blew its top in 1990, killing dozens. In 1919, a powerful explosion destroyed a hundred villages and claimed 5,160 lives.
Strato volcanoes are unpredictable and can unleash highly pressured gases and hot magma in a violent eruption without warning signs like smoke or ash.
Among those refusing to leave a 6 mile danger zone around the mountain were 80-year-old Kamisah and her handicapped son Yassir, who survived the last blast after shutting the doors and windows and hiding inside.
"Whatever happens, we put our lives in God's hands," she said Wednesday from their hillside farmhouse where the family collects hay to sell to local livestock farmers. "We were shaking with fear, but we were lucky."
Scientists say the temperature of a crater-lake formed in the massive 1919 blast is rapidly heating up and hundreds of volcanic earthquakes deep inside the mountain - far more than preceded the eruption 17 years ago - have been recorded in recent days.
"We know the danger. What others decide to do is beyond our capability," said government vulcanologist Surono, who goes by a single name.
The volcano's explosive activity typically starts with a steam blast - when surfacing magma meets ground water, producing hot mud flows, pyroclastic surges and ash clouds.
Pressure has built up in a chamber under the crater, Surono said, but did not yet have enough force to break through.
In 1919, the flows traveled 24 miles in less than an hour, devastating vast tracts of farmland. A drainage system, established by the Dutch in the 1920s, maintains low water levels in the crater lake aimed at reducing damage.
On Tuesday night, as many as 116,000 people were ordered to evacuate villages in the area.
Despite the danger, local government official Sigit Rahardjo said most of them returned home the next morning after complaining they had received no food and needed to tend crops and livestock.
Witnesses saw scores of trucks loaded with people and thousands of motorbikes leaving temporary evacuation camps and heading back up the mountain. Scores of people were seen working in villages close to the 5,679-foot volcano.
"There was no food at all," said Darmiashiah, a 33-year-old woman who returned to the village of Sugihwaras, well within in the evacuation zone. "If I get told to leave again, I will not go," said Darmiashiah, who goes by a single name.
Indonesia, which has around 150 active volcanoes spread across 17,500 islands, sits on the so-called Pacific "Ring of Fire" - a series of volcanoes and fault lines stretching from the Western Hemisphere through Japan and Southeast Asia.
Evacuation orders are often patchily enforced. Without compensating farmers for loses to crops or livestock, it is difficult to force them to leave their villages. Another worry for homeowners is thieves targeting empty properties.
Many people were heeding the warning, however.
"I can still remember the last eruption," said 70-year-old Kasemi who was staying in a government building with dozens of other people. "It went dark because of the ash and the explosions were terrifying."