Sumatra Places of Interest

"Sumatra Attractions"


Mount Merapi

Mount Merapi, Gunung Merapi in Indonesian language, is a conical volcano in Central Java, Indonesia. It is the most active volcano in Indonesia and has erupted regularly since 1548. Its name means Mountain of Fire. It is very close to the city of Yogyakarta, and thousands of people live on the flanks of the volcano, with villages as high as 1700 m above sea level.

Several of its eruptions have caused fatalities. It was erupting from 1992 to 2002, and a particularly large explosion killed 43 people in 1994. It began erupting again in 2006, and scientists believe a large eruption is imminent. In light of the hazards it poses to populated areas, it has been designated a Decade Volcano.

Geological history

Merapi is the youngest in a group of volcanoes in southern Java. It is situated at a subduction zone, where the Indo-Australian Plate is sliding beneath the Eurasian Plate. It is one of at least 129 active volcanoes in Indonesia, part of the Pacific Ring of Fire - a section of fault lines stretching from the Western Hemisphere through Japan and South East Asia.[1] Stratigraphic analysis reveals that eruptions in the Merapi area began about 400,000 years ago, and from then until about 10,000 years ago, eruptions were typically effusive, and the outflowing lava emitted was basaltic. Since then, eruptions have become more explosive, with viscous andesitic lavas often generating lava domes. Dome collapse has often generated pyroclastic flows, and larger explosions, which have resulted in eruption columns, have also generated pyroclastic flows through column collapse.

Typically, small eruptions occur every two to three years, and larger ones every 10-15 years or so. Notable eruptions, often causing many deaths, have occurred in 1006, 1786, 1822, 1872 (the most violent eruption in recent history), and 1930—when thirteen villages were destroyed and 1400 people killed by pyroclastic flows.

A very large eruption in 1006 is claimed to have covered all of central Java with ash. The volcanic devastation is claimed to have led to the collapse of the Hindu Kingdom of Mataram, however there is insufficient evidence from that era for this to be substantiated.

Merapi continues to hold particular significance for the Javanese: it is one of four places where officials from the royal palaces of Java's Yogyakarta and Solo make annual offerings to placate the ancient Javanese spirits.


Lake Singkarak

Lake Singkarak (Indonesian: Danau Singkarak) is a lake in West Sumatra, Indonesia. It is located between the cities of Padang Panjang and Solok, at 0°37′12″S, 100°32′24″E. It has an area of 107.8 km², being approximately 21 km long and 7 km wide. The natural outlet for excess water is the Ombilin river which flows eastward to the Strait of Malacca. A hydroelectric project however has diverted most of the lake outflow to the Anai river which flows westward into the Indian Ocean near Padang. This Singkarak power station uses this water to generate power for the West Sumatra and Riau provinces. A species of fish called ikan bilih (Mystacoleucus padangensis) is endemic to the lake, and is harvested for human consumption.

Bukittinggi

Bukittinggi (Indonesian for "high hill") is one of the larger cities in West Sumatra, Indonesia, with a population of over 91,000 people and an area of 25.24 km². It is situated in the Minangkabau highlands, 90 km by road from the West Sumatran capital city of Padang. It is located at 0°18′20″S, 100°22′9″E, near the volcanoes Mount Singgalang (inactive) and Mount Marapi (still active). At 930 m above sea level, the city has a cool climate with temperatures between 16.1°-24.9°C

History

The city was also known as Fort de Kock during colonial times in reference to the Dutch outpost established here in 1825 during the Padri War. During the Japanese occupation of Indonesia in World War II, the city was the headquarters for the Japanese 25th Army, the force which occupied Sumatra. The headquarters was moved to the city in April 1943 from Singapore, and remained until the Japanese surrender in August 1945.

During the Indonesian War of Independence, Bukittinggi was the headquarters for the Emergency Government of the Republic of Indonesia (PDRI) from December 19, 1948 to July 13, 1949. From 1950 until 1957, Bukittinggi was the capital city of a province called Central Sumatra, which encompassed West Sumatra, Riau and Jambi. In February 1958, during a revolt in Sumatra against the Indonesian government, rebels proclaimed the Revolutionary Government of the Republic of Indonesia (PRRI) in Bukittinggi. The Indonesian government had recaptured the town by May the same year.


Mentawai Islands

The Mentawai Islands are a chain of islands off the west coast of Sumatra in Indonesia. Siberut Island (4030 km²) is the largest island of the four Mentawai Islands. The other islands are Sipura, North Pagai (Pagai Utara) and South Pagai (Pagai Selatan). The islands lie approximately 150 km off the Sumatran coast, across the Mentawai Strait. The inhabitants of the islands are known as the Mentawai.

The Mentawai Islands are part of West Sumatra (Sumatera Barat) province. Padang, the capital of the province, lies on the Sumatran mainland opposite Siberut.

The Mentawai Islands are home to the Mentawai Islands rain forests ecoregion, home to many endemic species, including Four endemic primates: the Mentawai or Kloss Gibbon (Hylobates klossii), Mentawai Macaque (Macaca pagensis), Mentawai leaf-monkey (Presbytis potenziani), and snub-nosed monkey (Simias concolor).

The Mentawai Islands have become a noted destination for surfing.


Kerinci Seblat National Park

The Kerinci Seblat National Park comprises an area of 1.5 million ha in four provinces: West Sumatra, Jambi, Bengkulu and South Sumatra. A large part of the biggest national park of Sumatra lies above 400 m and is relatively cool. The park probably contains the largest contiguous population of the Sumatran Rhino, estimated at between 250 and 500 individuals.

Due to the fact that a large part of Bukit Barisan Mountain range, including it's highest peak the Gunung Kerinci (3,805m), lies in the park, Kerinci Seblat consists of very mountainous terrain. In the mountains you will find hot springs and many rivers with rapids and scenic waterfalls. Especially around the crater-lakes of Gunung Tujuh (2604m) and Gunung Kerinci, the landscape is very beautifull.

East of Gunung Kerinci lies lake Bento, the highest freshwater swamp in Sumatra. Ladeh Panjang is probably the highest peat swamp woodland (altitude 2,000 m).

The relatively flat Kerinci valley cuts the park in two and forms the main entrance to the area. The valley is situated at an altitude of 800 m and has a population of about 300,000 people.


Lake Toba, Sumatra

Lake Toba (Indonesian: Danau Toba) is a large lake, 100 km long and 30 km wide, in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about 900 m (3000 feet), stretching from 2.88° N 98.52° E to 2.35° N 99.1° E.

Geology  

In 1949 the Dutch geologist Rein van Bemmelen reported that Lake Toba was surrounded by a layer of ignimbrite rocks, and that it was a large volcanic caldera. Later researchers found rhyolite ash similar to that in the ignimbrite around Toba (now called Young Toba Tuff to distinguish it from layers deposited in previous explosions) in Malaysia and India, 3000 km away. Oceanographers discovered Toba ash, with its characteristic chemical "fingerprint", on the floor of the eastern Indian Ocean and the Bay of Bengal.


Gunung Leuser National Park

Gunung Leuser National Park is a national park covering 9,500 km² in northern Sumatra, Indonesia, straddling the border of North Sumatra and Aceh provinces. The national park, named after 3,381 m height of Mount Leuser, protects a wide range of ecosystems. An orangutan sanctuary of Bukit Lawang is located inside the park.


Danau Ranau

GEOLOGY

Danau Ranau is an arcuate shaped lake which partially wraps around G.Seminung (maximum elevation of 1880 m.a.s.l.). The thermal features in this prospect occur at two locations along the shoreline of D.Ranau, on the lower flanks of G.Semihung. Bahri (1972) calls one area Pagar Ratu (or Wai Werkuh). This is located 2 km west of Kota Batu. A flow of 0.6 kg/s is recorded at this site, but no temperature is indicated by Bahri (1972). The map of van Bemmelen (1933) show two springs at this location with temperatures of 48 and 56oC.

The second hot spring location is labelled as Tal.Waipanas by van Bemmelen (1933). Bahri (1972) records 4 hot springs here. The temperatures range between 59 and 65oC, which is slightly less than the 72oC indicated by van Bemmelen (1933). The total flow here is around 6 kg/s, and the heat flow is therefore almost 1 MW. The springs have a sufficient gas flux to give the appearance of boiling conditions.

The host rock at both hot spring locations andesite. Detailed geology has not been carried out in this area since van Bemmelen (1933). The general morphology of this area suggests G.Seminung could be relatively young. It is situated on the northwest-trending rift zone that traverses most of Sumatera.

GEOCHEMISTRY

Danau Ranau lies within an old caldera at 540 m.a.s.l. approximately 18 km from the west coast of Sumatera. Withinthe caldera and on the lakes's southern edge, lies G.Seminung (1881 m elevation a.s.l.), a young andesite volcano which is thought to be a volcanic risk (Akbar,N., pers.comm.). Hot near-neutral springs rise on its western and northern base close to the waters edge. The western spring is called Pagar Ratu or Wei Wertuh (Bahri, 1972) or Tal.Waipanas (van Bemmelen, 1933), has a temperature of 72oC and lies at 610 m.a.s.l. The other two springs lie 2 km west of Kotabato and have reported temperature ranging from 48oC to 65oC depending on the report. These springs are of higher flow (1 - 2 kg/s) than the western one. The limited data available indicate all springs have similar chemistries although their origin is confused. The spring chosen for the data sheet indicates some condensate and chloride fluid input although its nearest neighbour (same altitude) shows predominantly diluted sulphate water chemistry.

Approximately 6 km south-east of Kotabato, van Bemmelen (1933) reports a collapse structure at G.Kokosan (highest point 1562 m.a.s.l.). At the south-west base (about 650 m.a.s.l.) of this structure lies a 35oC spring, the chemistry of which is unknown. No other springs have been reported in the area.

Although Na-K-Ca geothermometers indicate temperatures in excess of 200oC, insufficient detailed chemistry is available to verify this. In the absence of for instance reliable silica levels, the prospect does not appear to have significant geothermal potential. However, its potential may warrant consideration for mini-turbine use.