Therefore, Mount Semeru is one of the highest mountains on the Java Island. It is a stratovolcano in the Bromo Tengger Semeru National Park. It covers some 800 square kilometers in the centre of East Java. At its northern end is the spectacular Tengger Caldera, Java’s largest, with its 10 km barren desert-like sea of sand. Within the caldera rise the deeply fissured volcanic cones of Mount Batok and Mount Bromo, the latter is still active with a cavernous crater from which smoke blows skyward. Temperatures at the top of Mount Bromo range about 5 to 18 degrees Celcius. To the South is a rolling upland plateau dissected by valleys and dotted with several small scenic lakes, extending to the foot of Mount Semeru, a towering grey forest-skirted cone dominating the southern landscape. The Gunung Bromo Tengger Semeru National Park is one of conservation areas which has been already well known by many people. This is proved with increasing of people to visit the park with various interests like for recreation, camping climbing, trekking, education and research.
Realizing that situation, the government had established Mount Bromo Tengger Semeru National Park area as a nasional park which was established on November 12, 1992 with the decree of Minister of Foresty No.1049/Kpts-Il/1992 with covering an area of 50.267,3 ha, which administratively is located in 4 regencies of Probolinggo, Pasuruan, Malang and Lumajang, East Java Province.
Mount Semeru is one of Indonesia’s most active volcanoes. Since 1818, at least 55 eruptions have been recorded (10 of which resulted in fatalities). The volcano belches out a huge cloud of steam and smoke every 20 minutes or so and sometimes interspersed with ash and stones.
Recently, the Mount Semeru East Java was erupted. Precisely on early Sunday, May 10,2009, it apparently erupted, spewing the smoke and ash high into the sky and coating a nearby town in black dust’. Recent cold volcanoes also flood the rivers around the Semeru villages. No evacuation has been ordered but volcanologists are monitoring the volcano closely ‘for signs of lethal heat clouds’ – the term often used in Indonesia for pyroclastic flows. The Indonesian volcano logical authorities said they do not need to raised the alert level at Semeru from the second highest level of ’siaga’ or orange. Proxy 15 sub district areas of Lumajang, East Java, Indonesia have an ash impact, especially they flow the agriculture areas.