"I'm scared and I don't want to do it again," said Cahyani, who is being treated for extensive burns at a hospital in Padang Panjang, a city in Western Sumatra province around 40 km (25 miles) from the volcano.

The 2,891-metre (9,485 ft) high Marapi is one of the most active volcanos in Indonesia, which straddles the so-called "Ring of Fire" tectonic belt that is home to about two-thirds of the world's total number of volcanos.

Marapi's eruption on Sunday was its third so far this year, and the deadliest since 1979.

Fifty-two people survived the eruption, including Cahyani and her friend Widya Azhamul Fadhilah who took shelter behind a huge rock on the side of the volcano as the ground shook and the air filled with sulphurous fumes that made it hard to breathe.

"She and I were already hypothermic, our hands and feet were hot and we were shivering violently," Cahyani added.

The women were with three other friends who also tried to escape the eruption. These friends have all died.

A few hours later, rescuers finally arrived.

"We asked to be carried, I did not want to use a stretcher because we were already in pain," Cahyani said.

This was her first hike, and would be her last, she added.

Since 2011, Indonesia's vulcanology agency has urged a local conservation agency and the environment ministry to close off an area within 3 km radius of the summit to climbers.

(Writing by Ananda Teresia, Editing by Kanupriya Kapoor and Miral Fahmy)

By Aidil Ichlas