Mount Rinjani or Gunung Rinjani is an active volcano in Indonesia on the island of Lombok. It rises to 3,726 m (12,224 ft), making it the second highest volcano in Indonesia. The first historical eruption occurred in September of 1847. The most recent eruption of Mount Rinjani was on 1 October 2004. The volcano and spectacular Segara Anak crater lake, are protected by a national park established in 1997. The 6 km by 8.5 km oval-shaped caldera is filled partially by a lake known as Segara Anak. The eruptions of 1994, 1995, and 1996 have formed a small cone in the center of the caldera and lava flows from these eruptions have entered the lake.

Rinjani is located in a caldera 2.4 km by 4.8 km in size.
There are two active centres located in the eastern part of caldera - Barujari and Rombongan cones. Segara Anak Lake is situated inside the caldera.

The highlands are forest clad and mostly underdeveloped. The lowlands are highly cultivated. Rice, soybeans, coffee, tobacco, cotton, cinnamon, and vanilla are the major crops grown in the fertile soils of the island.
 

Rinjani volcano on the island of Lombok rises to 3726 m, second in height among Indonesian volcanoes only to Sumatra's Kerinci volcano. Rinjani has a steep-sided conical profile when viewed from the east, but the west side of the compound volcano is truncated by the 6 x 8.5 km, oval-shaped Segara Anak caldera. The western half of the caldera contains a 230-m-deep lake whose crescentic form results from growth of the post-caldera cone Barujari at the east end of the caldera. Historical eruptions at Rinjani dating back to 1847 have been restricted to Barujari cone and consist of moderate explosive activity and occasionallava flows that have entered Segara Anak lake.
 

Eruptions of Rinjani Volcano
2004, 1994, 1966, 1965, 1953, 1949-50, 1944-45, 1941?, 1915, 1909, 1906, 1901, 1900, 1884, 1847
 

On 3 November 1994, a cold lahar from the summit area of Rinjani Volcano traveled down the Kokok Jenggak River.
Thirty people from the village of Aikmel who were collecting water from the river were killed.

Rinjani volcano on Lombok Island is one of Indonesia's highest volcanoes, rising to 3726 m. As seen here from the village of Sembalum Lawang to the NE, Rinjani has a symmetrical profile, but its western side is truncated by the 6 x 8.5 km, oval-shaped Segara Anak caldera. Historical eruptions have been recorded since 1847 from Gunung Barujari, a pyroclastic cone within the caldera.