Rajabasa is an isolated 1281-m-high conical

Volcanic cone

Volcanic cones are among the simplest volcanic formations. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and size of the fragments ejected during the eruption...

 volcano

Volcano

2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...

 along the Sunda Strait

Sunda Strait

The Sunda Strait is the strait between the Indonesian islands of Java and Sumatra. It connects the Java Sea to the Indian Ocean...

 located at the most South-Eastern point of Sumatra

Sumatra

Sumatra is an island in western Indonesia, westernmost of the Sunda Islands. It is the largest island entirely in Indonesia , and the sixth largest island in the world at 473,481 km2 with a population of 50,365,538...

.
It has a well-preserved 500 x 700 m summit crater with a swampy floor, the volcano is covered with vegetation. Although fumarolic

Fumarole

A fumarole is an opening in a planet's crust, often in the neighborhood of volcanoes, which emits steam and gases such as carbon dioxide, sulfur dioxide, hydrochloric acid, and hydrogen sulfide. The steam is created when superheated water turns to steam as its pressure drops when it emerges from...

activity occurs on the foot and flanks of the volcano and increased activity was reported in April 1863 and May 1892 it is not known when it last erupted.