Mount Rinjani is an Active volcano indonesia on the island of Lombok. Administratively the mountain is in the :Regency of North Lombok, Indonesia It rises to 3,726 metres (12,224 ft), making it the second highest volcano in Indonesia.It is also the highest point in the Indonesian province of West Nusa Tenggara. Adjacent to the volcano is a 6-by-8.5-kilometre (3.7 by 5.3 mi)caldera,which is filled partially by the crater lake known as segara anak(Child of the Sea) due to the color of its water, as blue as the sea (laut). This lake is approximately 2,000 metres (6,600 ft) above sea level and estimated to be about 200 metres (660 ft) deep, the caldera also contains Hot Springs.The lake and mountain are sacred to the local ethnically sasak people and also to some Hindus, and are the site of religious rituals. UNESCO made Mount Rinjani Caldera a part of the Global Geopark Network in April 2018. Its catastrophic Eruption in 1257 was the largest volcanic eruption in the last 2000 years.
History
The oldest recorded historical eruption was in 1847. Previous to that this was a very remote region indeed, hence the lack of records.
There was a spate of activity from 1994 to 1995 which resulted in the further growth of the crater cone Gunung Baru, since renamed Gunung Barujari (Finger Mountain).
On 27 April 2009 Gunung Barujari became active again with that activity continuing through to May 2009. The summit ascent routes were closed at that time as the eruptions intensified with plumes of smoke and ash as high as 8,000 m. A Volcanic Explosivity Index (VEI):2 rating was issued for the activity between May and December 2009. The ascent routes re-opened on September 14th 2009 but hiking routes down into the crater lake were still deemed unsafe and remained closed.
In February 2010 observers at the Gunung Rinjani Observation Post detected a smoke plume that rose 100 m from the volcano. The activity in early 2010 is centred about Gunung Barujari. On May 1st 2010 a column of smoke was again observed rising from Rinjani issuing eruptions 1,300-1,600 metres tall with thick brown color and strong pressure. On May 5th 2010 a possible ash plume rose to an altitude of 5.5 km (18,000 ft) and drifted 150 km NW. Accordingly the Center of Volcanology and Geological Hazard Mitigation advised that intermittent activity could produce ash plumes to 1,500 m (5,000 ft) above the caldera. In light of this The Volcanic Explosivity Index Alert Level was raised to 2 with a recommendation that there be no activity within a radius of 4 km from the eruption at Gunung Barujari.
Flora and fauna
The lower and middle elevation slopes are densely forested with typical tropical species, including species which occupy the Wallacea transitional region between the SE Asian and Australasian flora. Fig trees are especially apparent in the lower forests, as are the giant Syzigium Jambu, with the gnarled and epiphyte-hung Engelhardia Bak Bakan becoming prominent in the higher elevations. Casuarina woodland (cemara) takes over higher up and eventually these give way to an alpine flora above the treeline.
Lombok is East of the Wallace Line and some bird species with Australasian affinities are therefore apparent. These include honeyeaters, cockatoos and green hanging parrots, in addition to species whose heartland is to the West including tits, weavers and tailor-birds. Bird life can be difficult to observe here due to the density of the forest, though if you have patience and are practised at mimicry many species can be tempted out from cover – if you have the time to spare and the forebearance of your trekking partners.
The familiar long-tailed grey macaque (the Bali temple monkey) is common right up to the crater rim. Of much more interest is the rare ebony leaf monkey which inhabits these forests and whose soft hooting contact call often provides a soothing backdrop to the birdsong. Rusa deer and muntjacs are more often heard than seen.
References
Global Volcanism Program – Mount Rinjani
UNESCO Global Geoparks Network
Gunung Rinjani National Park Official Site
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