The Envisat satellite imaged the Mount Gamkonora volcano in Indonesia spewing hot ash and smoke into the air, as seen in this image taken by the MERIS instrument aboard the satellite.

8000 people have been evacuated due to fear of an imminent eruption, according to officials.

The alert was raised to the highest level on Tuesday after the volcano, located in the eastern province of North Maluku, started spitting out flaming material, indicating magma was approaching the crater's surface, making an eruption more likely, said Reuters news agency.

The 5360 foot (1635 meter) volcano, located about 1500 miles (2400 kilometers) northeast of Jakarta, began releasing smoke and ash on Saturday. Mount Gamkonora is the highest peak on Halmahera Island.

Satellite radar, such as that aboard Envisat and ERS-2, can track small changes in the Earth's movement that improves the ability to predict volcanic eruptions.

Combined radar and optical data acquired from space are also very useful when an eruption begins. Optical and radar instruments aboard Envisat can show the ash plume, the ash falling area, the lava streams and the volcanic cone shrinkage or expansion. Atmospheric sensors can identify the gases and aerosols released by the eruption, and quantify their wider environmental impact.

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--ESA and SPACE.com Staff

Credit: ESA