Central to the region is Mount Rinjani which at 3,726 m is the third highest mountain the second largest volcano in the country and is and an active volcano The oldest recorded historical eruption was in 1847 and last eruption was in May 2010. Gunung Rinjani Observation Post Rinjani Sembalun is located in the village of Lawang, Sub Sembalun 12.5 km (4000 feet) northeast of G. Rinjani. Observers at this post monitor G.Rinjani, and G.Barujari