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Mount Tambora, or Tomboro, is an active stratovolcano in West Nusa Tenggara, Indonesia. Located on Sumbawa in the Lesser Sunda Islands, it was formed by the active beneath it. Before the 1815 eruption, its elevation reached more than high, making it one of the tallest peaks in the Indonesian archipelago.
Tambora underwent a series of violent eruptions, beginning on 5 April 1815, and culminating in the largest eruption in recorded human history and the largest of the Holocene (10,000 years ago to present). The magma chamber under Tambora had been drained by previous eruptions and lay dormant for several centuries as it refilled. Volcanic activity reached a peak that year, culminating in an explosive eruption that was heard on Sumatra island, more than
away and possibly over away in Thailand and Laos. Heavy [[volcanic ash]] rains were observed as far away as [[Borneo]], [[Sulawesi]], [[Java]], and [[Maluku islands|Maluku Islands]], and the maximum elevation of Tambora was reduced from about . Estimates vary, but the death toll was at least 71,000 people. The eruption contributed to global [[climate]] anomalies in the following years, while 1816 became known as the "year without a summer" because of the effect on North American and European weather. In the Northern Hemisphere, crops failed and livestock died, resulting in the worst famine of the century.
Besides the and who monitor the mountain's activity, Mount Tambora is an area of interest to and . The mountain also attracts tourists for hiking and wildlife activities, though in small numbers. The two nearest cities are Dompu and Bima. There are three concentrations of villages around the mountain slope. At the east is Sanggar village, to the northwest are Doro Peti and Pesanggrahan villages, and to the west is Calabai village.
There are two routes of ascent to the caldera. The first begins at Doro Mboha village on the southeast of the mountain and follows a paved road through a cashew plantation to an elevation of . The road terminates at the southern part of the caldera, which at is reachable only by hiking. This location is only one hour from the caldera, and usually serves as a base camp from which volcanic activity can be monitored. The second route starts from Pancasila village at the northwest of the mountain and is only accessible on foot. The hike from Pancasila at elevation to the caldera of the volcano takes approximately 14 hours with several stops ( pos) en route to the top. The trail leads through dense jungle with wildlife such as Elaeocarpus, Asian water monitor, reticulated python, Accipiter, orange-footed scrubfowl, pale-shouldered cicadabird ( Coracina dohertyi), brown honeyeater and scaly-crowned honeyeater, yellow-crested cockatoo, yellow-ringed white-eye, helmeted friarbird, wild boar, Javan rusa and crab-eating macaques.
north of the [[Java Trench]] system and above the upper surface of the active north-dipping [[subduction zone]]. Sumbawa Island is flanked to the north and south by [[oceanic crust]]. The convergence rate of the [[Australian Plate]] beneath the [[Sunda Plate]] is per year. Estimates for the onset of the volcanism at Mount Tambora range from 57 to 43 [[ka|kiloannum]]. The latter estimate published in 2012 is based on argon dating of the first pre-caldera lava flows. The formation of Tambora drained a large [[magma chamber]] pre-existing under the mountain. The Mojo islet was formed as part of this process in which Saleh Bay first appeared as a [[sea basin]] about 25,000 years ago.
A high volcanic cone with a single central vent formed before the 1815 eruption, which follows a stratovolcano shape. The diameter at the base is . The volcano frequently erupted lava, which descended over steep slopes. Tambora has produced trachybasalt and trachyandesite rocks which are rich in potassium. The volcanics contain of apatite, biotite, clinopyroxene, leucite, magnetite, olivine and plagioclase, with the exact composition of the phenocrysts varying between different rock types. Orthopyroxene is absent in the trachyandesites of Tambora.Foden, 1979, p. 49 Olivine is most present in the rocks with less than 53 percent SiO2, while it is absent in the more silica-rich volcanics, characterised by the presence of biotite phenocrysts.Foden, 1979, p. 50 The mafic series also contain titanium magnetite and the trachybasalts are dominated by anorthosite-rich plagioclase.Foden, 1979, p. 51 Rubidium, strontium and phosphorus pentoxide are especially rich in the lavas from Tambora, more than the comparable ones from Mount Rinjani.Foden, 1979, p. 56 The lavas of Tambora are slightly enriched in zircon compared with those of Rinjani.Foden, 1979, p.60
The magma involved in the 1815 eruption originated in the mantle and was further modified by melts derived from sediments, fluids derived from the subducted crust and crystallization processes in . 87Sr86Sr ratios of Mount Tambora are similar to those of Mount Rinjani, but lower than those measured at Sangeang Api. Potassium levels of Tambora volcanics exceed 3 weight percent, placing them in the shoshonite range for alkaline series.
Since the 1815 eruption, the lowermost portion contains deposits of interlayered sequences of lava and Pyroclastic rock materials. Approximately 40% of the layers are represented in the lava flows. Thick scoria beds were produced by the fragmentation of lava flows. Within the upper section, the lava is interbedded with scoria, , and . Tambora has at least 20 and , including Doro Afi Toi, Kadiendi Nae, Molo and Tahe. The main product of these parasitic vents is basaltic .
In 1812, Mount Tambora became highly active, with its maximum eruptive intensity occurring in April 1815. The magnitude was 7 on the Volcanic Explosivity Index (VEI) scale, with a total tephra ejecta volume of up to 1.8 × 1011 cubic metres. Its eruptive characteristics included central vent and explosive eruptions, pyroclastic flows, and caldera collapse. This eruption had an effect on global climate. Volcanic activity ceased on 15 July 1815. Activity resumed in August 1819—a small eruption with "flames" and rumbling , and was considered to be part of the 1815 eruption. This eruption was recorded at 2 on the VEI scale.
Around 1880 ± 30 years, eruptions at Mount Tambora have been registered only inside the caldera. It created small lava flows and lava dome extrusions; this was recorded at two on the VEI scale. This eruption created the Doro Api Toi parasitic cone inside the caldera.
Mount Tambora is still active volcano and minor lava domes and flows were extruded on the caldera floor during the 19th and 20th centuries. The last eruption was recorded in 1967. It was a gentle eruption with a VEI of 0, which means it was non-explosive. Another very small eruption was reported in 2011. In August 2011, the alert level for the volcano was raised from level I to level II after increased activity was reported in the caldera, including earthquakes and steam emissions.
A moderate-sized eruption on 5 April 1815 was followed by thunderous detonation sounds that could be heard in Ternate on the Molucca, from Mount Tambora. On the morning of 6 April 1815, volcanic ash began to fall in East Java, with faint detonation sounds lasting until 10 April. What was first thought to be the sound of firing guns was heard on 10 and 11 April on Sumatra island (more than away), Cited by Oppenheimer (2003) and possibly over away in Thailand and Laos.
The eruptions intensified at about 7:00 p.m. on the 10th. Three plumes rose and merged. Pieces of pumice of up to in diameter rained down at approximately 8 p.m., followed by ash at around 9–10 p.m. The eruption column collapsed, producing hot that cascaded down the mountain and towards the sea on all sides of the peninsula, wiping out the village of Tambora. Loud explosions were heard until the next evening, 11 April. The veil of ash spread as far as West Java and South Sulawesi, while a "nitrous odor" was noticeable in Jakarta. The heavy tephra-tinged rain did not recede until 17 April. Analysis of various sites on Mount Tambora using ground-penetrating radar has revealed alternations of pumice and ash deposits covered by the pyroclastic surge and flow sediments that vary in thickness regionally.
The eruption is estimated to have had a Volcanic Explosivity Index of 7. It had 4–10 times the energy of the 1883 Krakatoa eruption. from the Past ; article; July,; By Robert Evans; Smithsonian Magazine, online; accessed September 10, 2020 An estimated of pyroclastic trachyandesite was ejected, weighing approximately 1.4×1014 kg. This has left a caldera measuring across and deep. The density of fallen ash in Makassar was 636 kg/m3. Before the explosion, Mount Tambora was approximately high, one of the tallest peaks in the Indonesian archipelago. After the eruption of 1815, the maximum elevation was reduced to . (1996). 9789625930763, Periplus Editions Ltd.. ISBN 9789625930763
The 1815 Tambora eruption is the largest and most devastating observed eruption in recorded history; a comparison with other major eruptions is listed below. The explosion was heard or away, and ash deposits were registered at a distance of at least . A pitch of darkness was observed as far away as from the mountain summit for up to two days. Pyroclastic flows spread to distances of about from the summit and an estimated 9.3–11.8 × 1013 g of stratospheric sulfate aerosols were generated by the eruption.
A moderate tsunami struck the shores of various islands in the Indonesian archipelago on 10 April, with waves reaching in Sanggar at around 10 p.m. A tsunami causing waves of was reported in Besuki, East Java before midnight and another exceeded in the Molucca. The eruption column reached the stratosphere at an altitude of more than . Coarser ash particles fell one to two weeks after the eruptions, while finer particles stayed in the atmosphere for months to years at an altitude of . There are various estimates of the volume of ash emitted: a recent study estimates a dense-rock equivalent volume for the ash of and a dense-rock equivalent volume of for the pyroclastic flows. Longitudinal winds spread these fine particles around the globe, creating optical phenomena. Between 28 June and 2 July, and between 3 September and 7 October 1815, prolonged and brilliantly coloured sunsets and twilights were frequently seen in London. Most commonly, pink or purple colours appeared above the horizon at twilight and orange or red near the horizon.
| + Comparison of major volcanic eruptions | ||||||
| unlikely | ||||||
| ? | ||||||
| ? | ||||||
| ? | ||||||
| ≈1,400 | ||||||
| >71,000 | ||||||
| 36,600 | ||||||
| 7,000–13,000 | ||||||
| 2 | ||||||
| 57 | ||||||
| >2,000 | ||||||
| 23,000 | ||||||
| 1,202 | ||||||
| 6 | ||||||
| Sources: Oppenheimer (2003), and Smithsonian Institution's Global Volcanism Program | ||||||
In the spring and summer of 1816, a persistent stratospheric sulfate aerosol veil, described then as a "dry fog", was observed in the northeastern United States. It was not dispersed by wind or rainfall, and it reddened and dimmed sunlight to an extent that sunspots were visible to the naked eye. Areas of the northern hemisphere suffered extreme weather conditions and 1816 became known as the "year without a summer". Average global temperatures decreased about , enough to cause significant agricultural problems around the globe. After 4 June 1816, when there were frosts in Connecticut, cold weather expanded over most of New England. On 6 June 1816, it snowed in Albany, New York and Dennysville, Maine. Similar conditions persisted for at least three months, ruining most crops across North America while Canada experienced extreme cold. Snow fell until 10 June near Quebec City, accumulating to .
That year became the second-coldest year in the northern hemisphere since 1400, while the 1810s were the coldest decade on record, a result of Tambora's eruption and other suspected volcanic events between 1809 and 1810. (See sulfate concentration chart.) Surface-temperature anomalies during the summers of 1816, 1817 and 1818 were −0.51, −0.44 and −0.29 °C, respectively. Along with a cooler summer, parts of Europe experienced a stormier winter, and the Elbe River and Ohře Rivers froze over for twelve days in February 1816. As a result, prices of wheat, rye, barley and oats rose dramatically by 1817.
This climate anomaly has been cited as a reason for the severity of the 1816–19 typhus epidemic in southeast Europe and the eastern Mediterranean. Large numbers of livestock died in New England during the winter of 1816–1817, while cool temperatures and heavy rains led to failed harvests in the British Isles. Families in Wales travelled long distances as refugees, begging for food. Famine was prevalent in north and southwest Ireland, following the failure of wheat, oat and potato harvests. The crisis was severe in Germany, where food prices rose sharply. Demonstrations at grain markets and bakeries, followed by riots, arson and looting, took place in many European cities. It was the worst famine of the 19th century.
Based on the artifacts found, such as bronzeware and finely decorated china possibly of or origin, the team concluded that the people were well-off traders. The Sumbawa people were known in the East Indies for their horses, honey, sappan wood (for producing red dye), and sandalwood (for incense and medications). The area was thought to be highly productive agriculturally.
The tambora language was lost with the eruption. Linguists have examined remnant lexical material, such as records by Zollinger and Raffles, and established that Tambora was not an Austronesian language, as would be expected in the area, but possibly a language isolate, or perhaps a member of one of the families of found or more to the east.
The eruption is captured in latter-day folklore, which explains the cataclysm as divine retribution. A local ruler is said to have incurred the wrath of Allah by feeding dog meat to a hajji and killing him. This is expressed in a poem written around 1830:
Resettlement of the area began in 1907, and a coffee plantation was established in the 1930s in the Pekat village on the northwestern slope. A dense rain forest of Duabanga moluccana trees had grown at an altitude of . It covers an area up to . The rain forest was discovered by a Dutch team, led by Koster and de Voogd in 1933. From their accounts, they started their journey in a "fairly barren, dry and hot country", and then they entered "a mighty jungle" with "huge, majestic forest giants". At , the trees became thinner in shape. Above , they found Dodonaea viscosa flowering plants dominated by Casuarina trees. On the summit was sparse Edelweiss and Wahlenbergia.
An 1896 survey records 56 species of birds including the crested white-eye. Several other zoological surveys followed and found other bird species, with over 90 bird species discoveries in this period, including yellow-crested cockatoos, Zoothera thrushes, , green junglefowl and are hunted for the cagebird trade by the local people. Orange-footed scrubfowl are hunted for food. This bird exploitation has resulted in population declines, and the yellow-crested cockatoo is nearing extinction on Sumbawa island.
A commercial logging company began to operate in the area in 1972, posing a threat to the rain forest. The company holds a timber-cutting concession for an area of , or 25% of the total area. Another part of the rain forest is used as a hunting ground. In between the hunting ground and the logging area, there is a designated wildlife reserve where deer, , Feral pig, bats, and species of reptiles and birds can be found. In 2015, the conservation area protecting the mountain's ecosystem was upgraded to a national park.
Seismology in Indonesia is monitored by the Directorate of Volcanology and Geological Hazard Mitigation with the monitoring post for Mount Tambora located at Doro Peti village. They focus on seismic and tectonic activity by using a seismograph. There has been no significant increase in seismic activity since the 1880 eruption. Monitoring is continuously performed inside the caldera, with a focus on the parasitic cone Doro Api Toi.
The directorate created a disaster mitigation map for Mount Tambora, which designates two zones for an eruption: a dangerous zone and a cautious zone. The dangerous zone identifies areas that would be directly affected by pyroclastic flows, lava flows or pyroclastic falls. It includes areas such as the caldera and its surroundings, a span of up to where habitation is prohibited. The cautious zone consists of land that might be indirectly affected, either by lahar flows and other pumice stones. The size of the cautious area is , and includes Pasanggrahan, Doro Peti, Rao, Labuan Kenanga, Gubu Ponda, Kawindana Toi and Hoddo villages. A river, called Guwu, at the southern and northwest part of the mountain is also included in the cautious zone.
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