https://phys.org/news/2018-06-indonesia-merapi-volcano-ejects-towering.html

It said the eruption at 8.20 a.m. caused no panic and nearby Adi Sucipto Yogyakarta International Airport is still open to flights.

The mountain is about 30 kilometers (18 miles) from center of Yogyakarta city on the densely populated island of Java.