Gunung Baru (volcano, Lombok)

Gunung Baru — literally "new mountain" in Indonesian — is a secondary volcanic cone nestled within the Rinjani caldera on the island of Lombok. Rising from the waters of Lake Segara Anak during recent eruptions, it forms an active crater in constant evolution. Hikers descending toward the lake from the Rinjani's main crater encounter it in the foreground, smoking gently, set against a backdrop of black lava and turquoise water.

Quick facts

• Access: on foot only, via trails within the Rinjani National Park (Taman Nasional Gunung Rinjani).
• Entry: included in the national park entrance permit, which is mandatory.
• Recommended duration: the descent to Lake Segara Anak and return constitute a full stage within a 2 to 4-day trek.
• Gear: technical hiking equipment recommended — unstable volcanic terrain, lava scree.
• Restrictions: ascending the cone itself may be prohibited depending on the level of volcanic activity; check the alert status with the park before departure.

What you'll see

Gunung Baru rises at the center of Lake Segara Anak, at approximately 2,400 meters elevation. Its black lava cone contrasts with the blue-green waters of the caldera lake. Fumaroles regularly escape from its summit. On the lake's shores, geothermal hot springs allow for bathing — a cherished moment for hikers after the effort of the descent.

History and context

Rinjani is one of the most active volcanoes in Indonesia. Gunung Baru emerged within its caldera following documented eruptions in the 20th century, with notable activity in the 1990s and 2000s. Its name reflects this recent origin. For the Sasak people and Hindu Balinese, Lake Segara Anak and the Rinjani massif hold sacred significance: annual pilgrimages are organized there.

Highlights of the visit

The descent to Lake Segara Anak

From the edge of the Rinjani crater, the descent to the lake is steep and spectacular. Gunung Baru appears progressively, framed by the caldera walls. The contrast between the dark lava of the cone and the lake's color is striking.

Hot springs by the lake

On the northeast shore of Lake Segara Anak, natural geothermal springs allow bathing in warm water. After a night at altitude, this is a cherished rest stop for trekkers before the climb back up.

Observing the active cone

Depending on the level of volcanic activity, it is sometimes possible to approach the base of Gunung Baru. The fumaroles, sulfur deposits and recent lava provide direct evidence of the site's geological dynamism.

Photography tips

Morning light, just after descending from the crater, offers the best angle: the cone is front-lit and reflections on the lake are sharp. In late afternoon, mist often settles in the caldera. A wide-angle lens allows you to frame the cone with the caldera walls in the background. Avoid midday hours when light is harsh and flat.

Location and access

Gunung Baru lies within the Rinjani caldera, in northern Lombok. Typical starting points for the trek are Senaru (north) and Sembalun (east). From Mataram, the provincial capital, plan for several hours of travel to the departure villages. No motorized access exists within the park. Accessibility for people with reduced mobility is non-existent — the terrain is exclusively on foot and technical.

Nearby

• Mount Rinjani — the presiding volcano whose caldera Gunung Baru occupies; its summit at 3,726 m is the main objective for trekkers.
• Lake Segara Anak — the caldera lake that surrounds Gunung Baru, with hot springs on its shores.
• Senaru Village — northern starting point of the trek, with waterfalls accessible without specialist equipment.
• Sembalun Valley — eastern starting point, at higher elevation, with savanna landscapes and garlic fields.