Radius beware Merapi in Sleman reduced from 20 km to 10 km to the west of the Kali Boyong and 15 km east of Kali Boyong. Residents and visitors are also not advisable to do any activity, especially in areas covered with volcanic material (debris) because it is still hot.According to the National Disaster Management Agency (BNPB), at a depth of 20 centimeters from the surface of the debris, hot volcanic material reached more than one hundred degrees Celsius.
