Japanese researchers have unveiled a prototype robot that can monitor the crater of a volcano while it is erupting.

A group of researchers from Tohoku University and other institutions developed the robot, which is made of two parts.

One is an electric-powered flying module that can operate above mountaintops where the air is thinner.

The other is a 2kg vehicle that moves along the ground.

When the flying robot reaches a monitoring site, the ground vehicle separates from it and is guided to earth by remote control.

The camera-equipped ground vehicle sends images that can reveal the risk of mudslides caused by volcanic ash.

The test flight was carried out at Mt. Asama, in the central Japanese prefectures of Nagano and Gunma.

Researchers confirmed they were able to operate the robot via remote control from a computer about 3km away.

But the surface vehicle failed to separate, and the robot fell to the earth after reaching an altitude of one meter.

Keiji Nagatani, associate professor at Tohoku University graduate school, says the robot will be able to provide important information during volcanic eruptions.

He also says the group will continue to test the robot for practical application.