Volcanic ash rain blanketed at least eight villages near the volcano after last week's eruption.
Volcanologists said last week the volcano is experiencing its most active phase since 2021.
Merapi has been at the second-highest level alert since 2020 following increased volcanic activity and authorities established a restricted zone of seven kilometres from the summit.
The volcano's last major eruption in 2010 killed more than 300 people and forced the evacuation of some 280,000 residents.
It was Merapi's most powerful eruption since 1930 when about 1,300 people were killed. An eruption in 1994 left about 60 people dead.
