Visit Indonesia: April 2011

Lake Toba (Indonesian: Danau Toba) is a lake and supervolcano. The lake is 100 kilometres long and 30 kilometres wide, and 505 metres (1,666 ft) at its deepest point. Located in the middle of the northern part of the Indonesian island of Sumatra with a surface elevation of about 900 metres (2,953 ft), the lake stretches from 2.88°N 98.52°E to 2.35°N 99.1°E. It is the largest lake in Indonesia and the largest volcanic lake in the world.

Lake Toba is the site of a supervolcanic eruption that occurred 69,000-77,000 years ago, a massive climate-changing event. The eruption is believed to have had a VEI intensity of 8. It is believed to be the largest explosive eruption anywhere on Earth in the last 25 million years. According to the Toba catastrophe theory to which some anthropologists and archeologists subscribe, it had global consequences, killing most humans then alive and creating a population bottleneck in Central Eastern Africa and India that affected the genetic inheritance of all humans today. This theory however, has been largely debated as there is no evidence for any other animal decline or extinction, even in environmentally sensitive species. However, it has been accepted that the eruption of Toba led to a volcanic winter with a worldwide decline in temperatures between 3-5 degrees C, and up to 15 degrees C in higher latitudes.

Geology

The Toba caldera complex in Northern Sumatra, Indonesia consists of four overlapping volcanic craters that adjoin the Sumatran "volcanic front". The youngest and fourth caldera is the world's largest Quaternary caldera (100 km (62 mi) by 30 km (19 mi)) and intersects the three older calderas. An estimate of 2,800 km³ (670 cu mi) of dense-rock equivalent pyroclastic material, known the Youngest Toba tuff, was blasted from the youngest caldera during one of the largest single explosive volcanic eruptions in geologic history. Following the "Youngest Toba tuff eruption", a typical resurgent dome formed within the new caldera, joining two half-domes separated by a longitudinal graben.

There are at least four cones, four stratovolcanoes and three craters visible in the lake. The Tandukbenua cone on the NW edge of the caldera is relatively lacking in vegetation, suggesting a young age of only several hundred years. Also, the Pusubukit volcano on the south edge of the caldera is solfatarically active.

Borobudur, Barabudur, is a 9 Century mahayana buddist monument near magelang, Central Java, Indonesia. The monument comprises six square platforms topped by three circular platforms, and is decorated with 2,672 relief panels and 504 buddha statues. A main dome, located at the center of the top platform, is surrounded by 72 Buddha statues seated inside perforated stupa.The monument is both a sharie to the Lord buddha and a place for Buddhist pilgrimage. The journey for pilgrims begins at the base of the monument and follows a path circumambulating the monument while ascending to the top through the three levels of buddist cosmology , namely kamadhatu (the world of desire), rapadhatu (the world of forms) and arupadhatu (the world of formlessness). During the journey the monument guides the pilgrims through a system of stairways and corridors with 1,460 narrative relief panels on the wall and the balustrades.
Evidence suggests Borobudur was abandoned following the 14th-century decline of Buddhist and Hindu kingdoms in Java, and the Javanese conversion to Islam. Worldwide knowledge of its existence was sparked in 1814 by Sir Thomas Stamford Raffles, then the British ruler of Java, who was advised of its location by native Indonesians. Borobudur has since been preserved through several restorations. The largest restoration project was undertaken between 1975 and 1982 by the Indonesian government and UNESCO, following which the monument was listed as a UNESCO World Heritage Site. Borobudur is still used for pilgrimage; once a year Buddhists in Indonesia celebrate Vesak at the monument, and Borobudur is Indonesia's single most visited tourist attraction.

Location

Approximately 40 kilometers (25 mi) northwest of Yogyakarta, Borobudur is located in an elevated area between two twin volcanoes, Sundoro-Sumbing and Merbabu-Merapi, and two rivers, the Progo and the Elo. According to local myth, the area known as Kedu Plain is a Javanese 'sacred' place and has been dubbed 'the garden of Java' due to its high agricultural fertility.^[Besides Borobudur, there are other Buddhist and Hindu temples in the area, including the Prambanan temples compound. During the restoration in the early 20th century, it was discovered that three Buddhist temples in the region, Borobudur, Pawon andMendut, are lined in one straight line position. It might be accidental, but the temples' alignment is in conjunction with a nativefolk tale that a long time ago, there was a brick-paved road from Borobudur to Mendut with walls on both sides. The three temples (Borobudur–Pawon–Mendut) have similar architecture and ornamentation derived from the same time period, which suggests that ritual relationship between the three temples, in order to have formed a sacred unity, must have existed, although exact ritual process is yet unknown.

Unlike other temples, which were built on a flat surface, Borobudur was built on a bedrock hill, 265 m (869 ft) above sea level and 15 m (49 ft) above the floor of the dried-out paleolake. The lake's existence was the subject of intense discussion among archaeologists in the 20th century; Borobudur was thought to have been built on a lake shore or even floated on a lake. In 1931, a Dutch artist and a scholar of Hindu and Buddhist architecture, W.O.J. Nieuwenkamp, developed a theory that Kedu Plain was once a lake and Borobudur initially represented a lotus flower floating on the lake. Lotus flowers are found in almost every Buddhist work of art, often serving as a throne for buddhas and base for stupas. The architecture of Borobudur itself suggests a lotus depiction, in which Buddha postures in Borobudur symbolize the Lotus Sutra, mostly found in many Mahayana Buddhism (a school of Buddhism widely spread in the east Asia region) texts. Three circular platforms on the top are also thought to represent a lotus leaf. Nieuwenkamp's theory, however, was contested by many archaeologists because the natural environment surrounding the monument is a dry land.

Geologists, on the other hand, support Nieuwenkamp's view, pointing out clay sediments found near the site. A study of stratigraphy, sediment and pollen samples conducted in 2000 supports the existence of a paleolake environment near Borobudur, which tends to confirm Nieuwenkamp's theory. The lake area fluctuated with time and the study also proves that Borobudur was near the lake shore c. 13th and 14th centuries. River flows and volcanic activities shape the surrounding landscape, including the lake. One of the most active volcanoes in Indonesia, Mount Merapi, is in the direct vicinity of Borobudur and has been very active since the Pleistocene.