ACTNews, LUMAJANG – Mount Semeru, Java’s highest active volcano, has a long history of volcanic eruptions. The Volcanological Survey of Indonesia (PVMBG) under the Indonesian Ministry of Energy and Mineral Resources noted that the oldest record of Mount Semeru eruption dates back to 1818. However, the volcanic eruptions from 1819 to 1913 were not well documented.
From late 1941 to early 1942, a major volcanic eruption happened with lava flow occurring over a long period of time, from September 21, 1941, to February 1942. The flow reached the eastern slopes at an altitude between 1,400 to 1,775 meters.
PVMBG noted that the volcanic eruptions occurred at six points. The lava flowed to Besuk Semut and the Bantengan Watering Post, covering an area of 6.5 kilometers.
Mount Semeru was recorded to have erupted in 1945, 1946, 1947, 1950, 1951, 1952, 1953, 1954, 1955 to 1957, 1958, 1959, and 1960.
On December 1, 1977, a lava avalanche occurred and caused volcanic ash clouds that soared 10 km away in Besuk Kembar. The volume of the sediment reached 6.4 million m3. Some of these hot clouds also diverted to Besuk Kobokan.
110 hectares of rice fields in Sumberurip Village were damaged. 450 hectares of pine forest and one bridge were burned down. Two houses were swept away.
A village affected by the eruption of Mount Semeru on Saturday (12/4/201). (ACTNews/Akbar)
The volcanic eruptions of Mount Semeru continued in 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986 to 1989, 1990, 1992, 1994, 2002, 2004, 2005, 2007, and 2008. In 2008, a series of volcanic eruptions happened from May 15 to 22. During that period, sixteen hot cloud avalanches were recorded with a sliding distance of about 500 to 3,000 meters.
The activity of Mount Semeru is found in Jonggring Saloko Crater which is located to the southeast of the Mahameru peak. Semeru eruptions are generally of Vulcanian and strombolian characteristics that occur 3-4 times every hour.
Vulcanian-type eruptions are characterized by explosive eruptions that sometimes destroy pre-formed lava domes and tongues. Then there is the strombolian-type eruption which is usually followed by the formation of a new dome and lava tongue.
PVMBG explained, when an explosive eruption occurs, it is usually followed by a stream of hot clouds flowing into the valleys. The direction of the flow is in accordance with the openings of the craters and valleys. The direction of the opening of the crater of Mount Semeru is currently towards the southeast or towards the upstream of Besuk Kembar, Besuk Bang, Besuk Kobokan rivers.