East Java, Gunung Semeru

Written by on July 16, 2012 in Java Mountains with 0 Comments

East Java, Gunung Semeru



Semeru is Java’s highest peak and has been active for decades – a cloud of black volcanic ash and sand is frequently released from near the summit – sometimes once an hour, sometimes as often as every ten minutes. There have been numerous fatalities, but it is a popular and safe hike if you treat the mountain with respect and as Java’s highest peak, it is one of the finest hikes in Indonesia.

The trail starts at the village of Ranu Pani (2,109m) where there is basic accommodation available and you will need a minimum of two full days for the hike to the summit and back. There are many trekking agencies in East Java who offer jeep transport across the length and breadth of the National Park including the vast Bromo caldera and to Ranu Pani village itself from the city of Malang via Tumpang. Thankfully it is not yet possible to drive to the summit of Semeru! However, the road from Malang to Ranu Pani offers breathtaking views and reaches an elevation of over 2,400m at its highest point.

From Ranu Pani follow the road towards the lake which gives the village its name and make sure you take a right just before red entrance posts. A left turn up onto a narrow track through forest is just a couple of minutes further along and once you’re on this trail it is quite difficult to lose your way because there are frequent cement markers and green shelters at 2,284m, 2,346m and 2,426m respectively. The path is even paved at this point. Look out for monkeys in the area.

It’s a long 14km to Kalimati basecamp (2,669m) but the route goes via the beautiful Ranu Kumbolo lake (2,382m) which is a good camp spot in its own right. It can be reached in 4 hours from Ranu Pani but is famous for its low temperatures at night – frost is common so remember to take plenty of warm clothing and don’t leave your boots outside. There are a couple of huts on the far side of the lake before which the path ascends a hundred metres or so before descending again into an area which is sometimes covered in beautiful purple flowers. Kalimati – which lies beneath but in view of the rocky cone of Semeru summit itself – is another 3 hours of fantastic, easy hiking across savanna-esque landscapes and is perhaps marginally warmer. There is a somewhat shabby hut here and the flat area surrounding it is a very popular camping area and water is to be found about 15 minutes walk down to the right.

Another 2 km (one hour) is Arcopodo basecamp (2,912m), which is the best place to camp if you intend on reaching the summit at dawn and have the best chance of clear views and more importantly to avoid the worst of the gases. The path descends a little from Kalimati before ascending steeply up the forested base of the cone of Semeru itself. A lot of people choose to spend one night at Ranu Kumbolo and a second up at Arcopodo before making a pre-dawn ascent to the summit. There used to be a pair of statues at Arcopodo but it is presumed they were covered during landslides. There is plenty of flattish space for tents here – at least 10 – despite the generally steep pine forest terrain. It is about 3 hours from Arcopodo camp to the summit and the track is very steep. In some places lower down there are cement posts to guide you but many of them have long since toppled over and are buried in volcanic scree! The treeline ends at 3,110 and there are excellent views particularly to Arjuna. You may also spot some pre-dawn camera flashes from the famous viewpoint Gunung Pananjakan on the northern side of the Bromo caldera. The summit cone is very slippery with small volcanic rocks – definitely a case of two steps forward and one step back.

As you near the top you may literally feel the earth move as Semeru sends another cloud of volcanic sand into the air. There are lots of monuments to people have lost their lives up here but generally speaking the climb is safe – but do not head closer to the crater itself from the summit. The view from the rooftop of Java is as incredible as you might expect – a vast panorama of all of East Java’s major peaks, something to savour before the hike back to Ranu Pani, which can be done in one long day. The first section down the scree is a lot of fun – what takes 3 hours to climb takes just 1 hour to scree-slide down!

On the way back to Ranu Pani, the more adventurous may like to try an alternative route from Ranu Kumbolo back to the village via Gunung Ajekajek. It is a lot steeper – a 300m climb again – but marginally shorter in terms of both distance and time. If you have any energy left it makes an interesting alternative to the fairly bland plod along the normal route. Take a left turn at the lake and follow the path as it leads through lovely grassy flat landscapes before heading right up the hillside once more. After an hour you will be at the top of the pass (2,719m) which offers rarely-seen views of Semeru. Down below you in the opposite direction (north) is Ranu Pani and the Bromo caldera beyond. This now infrequently used trail used to be the main route to Semeru several decades ago.

Bagging information by Daniel Quinn.


Getting there

Best to arrange transport to Ranupani in advance. Malang is the closest city with an airport.


Basic accommodation available in Ranupani.


Available from the homestay in Ranupani – take a photocopy of your passport photo page. You also need to present a health certificate which must include a) blood pressure and b) data for body-mass-index.

Water sources

Available at Ranu Kumbolo and near Kalimati.

Country: Indonesia

Subregion Name: Java (Indonesia)

Volcano Number: 0603-30=

Volcano Type: Stratovolcano

Volcano Status: Historical

Last Known Eruption: 2011 (in or after)

Summit Elevation: 3676 m 12,060 feet

Latitude: 8.108°S 8°6’30″S

Longitude: 112.92°E 112°55’0″E

Semeru, the highest volcano on Java, and one of its most active, lies at the southern end of a volcanic massif extending north to the Tengger caldera. The steep-sided volcano, also referred to as Mahameru (Great Mountain), rises abruptly to 3676 m above coastal plains to the south. Gunung Semeru was constructed south of the overlapping Ajek-ajek and Jambangan calderas. A line of lake-filled maars was constructed along a N-S trend cutting through the summit, and cinder cones and lava domes occupy the eastern and NE flanks. Summit topography is complicated by the shifting of craters from NW to SE. Frequent 19th and 20th century eruptions were dominated by small-to-moderate explosions from the summit crater, with occasional lava flows and larger explosive eruptions accompanied by pyroclastic flows that have reached the lower flanks of the volcano. Semeru has been in almost continuous eruption since 1967.

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