RINJANI CONTINUES TO ERUPT

Nearly one year after the first eruption, Baru Jari, inside Mt Rinjani, continues to rumble, sometimes sending sprays of smoke and ash hundreds of metres into the air.

Mt Rinjani itself is an extinct volcano which, when it erupted centuries ago, lost most of its peak. The crater filled with water, creating the scenic Segara Anak Lake, and Mt Baru Jari, 2 363 metres above sea level, is the smaller active volcanic cone located alongside the lake inside the mountain's caldera.

The small volcano started erupting on 2 May 2009 and thus far has created a lava flow into the lake measuring about 500 m long and 200 m wide. The volume created by each eruption can not be calculated but the lava flow has covered about 600,000 cubic meters of the lake to a depth of 100 metres. Lake Segara Anak is around 1.1 hectares in area, and has an average depth of 120m, with the west side dropping to around 230 m.

The Centre for Volcanology and Disaster Mitigation installed a seismograph on the shoulder of the mountain last year and another is located at the Vulcanology Centre in Sembalun. Authorities say the eruptions are occurring on average 10 times a day, with some eruptions reaching 1000 m from Baru Jari, or 800 m from the lip of the caldera.
Last year, the eruptions caused the mountain to be closed to trekking, as authorities judged the conditions to be unsafe, with frequent earth tremors and dangerous gasses being released by the rumbling smaller volcano. By October last year, most activity had settled down.

This year, trekking season was officially opened on the mountain on 1 April 2010 and, at present, visitors are able to climb the mountain and have the rare opportunity to witness a live volcano in action.

Routes on the mountain are partially restricted, with trekkers being permitted to descend to the lake; however, camping is not allowed on the lake shores. Climbers may descend to the lake but must then return to the top, where they can camp overnight at either Plawangan 2 (Sembalun Crater Rim Camp) at 2 639 metres, or Plawangan 1 (Senaru Crater Rim) at 2 641 metres.

Climbing to the summit is also permitted, but this is subject to the trek leader's discretion. There is a possibility that this route will be closed, due to the danger of gasses and hot ash. Always check with your guide first, as they are regularly briefed on conditions on the mountain and know if the situation is dangerous.

Trekkers are requested to not touch or interfere with monitoring equipment currently collecting data on Rinjani at Sembalun Plawangan. Caution is advised in cases of strong winds which can blow heavy clouds of ash for several kilometres and large eruptions which can throw hot stones outside of the restricted zone.

Climbers must be accompanied by experienced guides who know the mountain and are briefed by the Department of Volcanology and the Rinjani Trek Management Board regularly. By : The Lombok Guide