The Semeru (), or Mount Semeru (, ) is an active

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

located in

East Java East Java (, , ) is a Provinces of Indonesia, province of Indonesia located in the easternmost third of Java island. It has a land border only with the province of Central Java to the west; the Java Sea and the Indian Ocean border its northern ...

, Indonesia. It is located in a subduction zone, where the Indo-Australian plate

subducts Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second pla ...

under the Eurasia plate. It is the highest

mountain A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher t ...

on the island of

Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...

. The name "Semeru" is derived from Meru, the central world mountain in

Hinduism Hinduism () is an Hypernymy and hyponymy, umbrella term for a range of Indian religions, Indian List of religions and spiritual traditions#Indian religions, religious and spiritual traditions (Sampradaya, ''sampradaya''s) that are unified ...

, or Sumeru, the abode of

gods A deity or god is a supernatural being considered to be sacred and worthy of worship due to having authority over some aspect of the universe and/or life. The ''Oxford Dictionary of English'' defines ''deity'' as a God (male deity), god or god ...

. This

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

is Mahameru, meaning "The Great Mountain" in

Sanskrit Sanskrit (; stem form ; nominal singular , ,) is a classical language belonging to the Indo-Aryan languages, Indo-Aryan branch of the Indo-European languages. It arose in northwest South Asia after its predecessor languages had Trans-cultural ...

. It is one of the more popular hiking destinations in Indonesia.

Geology

Semeru rises steeply above the coastal plains of eastern Java. Maars containing crater lakes have formed along a line through the volcano's summit. It was formed south of the overlapping Ajek-ajek and Jambagan

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption. An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the str ...

s. The eruptive products are

andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...

. Semeru lies at the south end of the Tengger Volcanic Complex.

Eruptive history

Semeru's eruptive history is extensive. Since 1818, at least 55 eruptions have been recorded (11 of which resulted in fatalities) consisting of lava and

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

s. All historical eruptions have had a

Volcanic Explosivity Index The volcanic explosivity index (VEI) is a scale used to measure the size of explosive volcanic eruptions. It was devised by Christopher G. Newhall of the United States Geological Survey and Stephen Self in 1982. Volume of products, eruption c ...

(VEI) of 2 or 3. Semeru has been in a state of near-constant eruption from 1967 to the present. The volcano's most recent eruption occurred in 2024. Semeru is regularly climbed by tourists, usually starting from the village of Ranu Pane to the north, but though non-technical, it can be dangerous. Soe Hok Gie, an Indonesian political activist of the 1960s, died in 1969 from inhaling poisonous gases while hiking on Mount Semeru.

2021 eruption

On 4 December 2021, Semeru erupted for a second time in the year – the first having been on 16 January 2021. Semeru erupted a third time on 6 December 2021. At least 57 people died, 104 more were injured, while 23 were unaccounted for. Thousands were displaced.

2022 eruption

A new eruption started on 4 December 2022, as monsoon rains collapsed the mountain's lava dome, provoking evacuations. A large pyroclastic flow reached up to from the summit crater, prompting evacuations.

Legends

Semeru is named after Sumeru, the central world mountain in

. As stated in legend, it was transplanted from

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

to create the island of Java; the tale is recorded in the 15th-century East Javanese work '' Tantu Pagelaran''. It was originally placed in the western part of the island, but that caused the island to tip, so the gods moved it eastward. On that journey, parts kept coming off the lower rim, forming the mountains Lawu, Wilis, Kelud, Kawi, Arjuno and Welirang. The damage thus caused to the foot of the mountain caused it to shake, and the top came off and created Penanggungan as well. Indonesian Hindus also hold a belief that the mountain is the abode of

Shiva Shiva (; , ), also known as Mahadeva (; , , Help:IPA/Sanskrit, ɐɦaːd̪eːʋɐh and Hara, is one of the Hindu deities, principal deities of Hinduism. He is the God in Hinduism, Supreme Being in Shaivism, one of the major traditions w ...

in Java.

Floral problems

Non-native invasive plants

25 non-native plants have been found in Mount Semeru National Park. The non-native plants, which threaten the

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

local plants, were imported by Dutch botanist Van Steenis, in the colonial era. They include '' Foeniculum vulgare'', '' Verbena brasiliensis'', ''

Chromolaena odorata ''Chromolaena odorata'' is also known as Jack in the Bush. It is a tropical and subtropical species of Flowering plant, flowering shrub in the family Asteraceae. It is native to the Americas, from Florida and Texas in the United States so ...

'', and '' Salvinia molesta''.

Vegetable plantations

Mud

erosion Erosion is the action of surface processes (such as Surface runoff, water flow or wind) that removes soil, Rock (geology), rock, or dissolved material from one location on the Earth's crust#Crust, Earth's crust and then sediment transport, tran ...

from surrounding vegetable plantations is adding silt to Ranu Pani Lake, causing the lake to gradually shrink. Research has predicted that the lake will disappear by about 2025, unless the vegetable plantations on the hillsides are replaced with more ecologically sustainable

perennials In horticulture, the term perennial ('' per-'' + '' -ennial'', "through the year") is used to differentiate a plant from shorter-lived annuals and biennials. It has thus been defined as a plant that lives more than 2 years. The term is also ...

Citations

General sources

* * Holt, Claire. ''Art in Indonesia: Continuities and Change''. Ithaca:

Cornell University Press The Cornell University Press is the university press of Cornell University, an Ivy League university in Ithaca, New York. It is currently housed in Sage House, the former residence of Henry William Sage. It was first established in 1869, maki ...

, 1967. Page 36 explains the mythological aspect of the mountain.

External links

Satellite picture by Google Maps Early December 2022 eruptions
at

NASA Earth Observatory NASA Earth Observatory is an online publishing outlet for NASA which was created in 1999. It is the principal source of satellite imagery and other scientific information about the climate and the environment which are being provided by NASA for ...

Semeru Volcano by Drone

Nov 5, 2024: Semeru Volcano Eruption Caught on Camera - YouTube
{{authority control Active volcanoes of Indonesia Maars of Indonesia Mountains of East Java Sacred mountains of Indonesia Stratovolcanoes of Indonesia VEI-3 volcanoes Volcanic crater lakes Volcanoes of East Java Holocene stratovolcanoes Volcanic eruptions in 2022 Brantas basin Glidik basin