2017–2018 eruptions of Mount Agung This article needs to be updated . Please update this article to reflect recent events or newly available information . ( April 2018 ) 2017 -- 2018 eruptions of Mount Agung Mount Agung on 27 November Volcano Mount Agung Date 21 November 2017 ( 2017 - 11 - 21 ) -- ongoing ( 11 months and 2 days ) Type Vulcanian / Sub-plinian Location Bali , Indonesia 8 ° 20 ′ 35 '' S 115 ° 30 ′ 25 '' E  /  8.34306 ° S 115.50694 ° E  / - 8.34306 ; 115.50694 Coordinates : 8 ° 20 ′ 35 '' S 115 ° 30 ′ 25 '' E  /  8.34306 ° S 115.50694 ° E  / - 8.34306 ; 115.50694 VEI 2 ( as of 2 Dec 2017 ) Mount Agung Location of Mount Agung , Bali Mount Agung , a volcano on the island of Bali in Indonesia , erupted five times in late November 2017 , causing thousands to evacuate , disrupting air travel and causing environmental damage . As of 27 November 2017 , the alert level was at its highest and evacuation orders were in place . Tectonic earthquakes from the volcano had been detected since early August , and volcanic activity intensified for several weeks before decreasing significantly in late October . A second , more violent period of major activity began in late November . Contents 1 Background 1.1 1843 eruption 1.2 1963 eruption 2 Major activity in 2017 2.1 August 2.2 September 2.3 October 2.4 November 2.4. 1 21 November 2.4. 2 25 November 2.4. 3 26 November 2.4. 4 27 November 2.4. 5 29 November 3 Activity in 2018 3.1 January 3.2 June 3.3 July 4 Impact 5 References Background ( edit ) 1843 eruption ( edit ) Agung erupted in 1843 as reported by Heinrich Zollinger : After having been dormant for a long time , this year the mountain began to be alive again . In the first days of the activity earthquake shocks were felt after which followed the emission of ash , sand and stones . 1963 eruption ( edit ) Mount Agung 's 1963 eruption was among the most catastrophic volcanic events in Indonesian history . After initial explosions in the crater on 18 February of that year , lava began flowing down the mountain on 24 February , eventually traveling 7 km over the next three weeks . On 17 March , a highly explosive eruption occurred , reaching a VEI ( Volcanic Explosivity Index ) of 5 and sending lethal pyroclastic flows at high speeds down the mountain 's slopes , killing at least 1,500 people . Heavy rainfall mixed with ash from the eruption in the following days caused extensive lahars which killed about 200 more people . A smaller eruption occurred on 16 May , sending pyroclastic flows down the mountain once more , killing about 200 more people . By the time the eruptions ceased in early 1964 , they had claimed about 1,900 lives , marking the event as the 8th deadliest volcanic eruption of the 20th century . Since 1963 , the population of Bali has nearly doubled . Mount Agung is therefore considered highly dangerous by Indonesian authorities . This concern was the primary reason behind their decision to evacuate more than 100,000 people in response to the surge in local tectonic activity in the latter half of 2017 . Major activity in 2017 ( edit ) August ( edit ) Volcanic earthquakes were observed from 10 August 2017 and the intensity increased in the following weeks . September ( edit ) In September 2017 , an increase of rumbling and seismic activity around the volcano made people raise the alert to the highest level and about 122,500 people were evacuated from their homes around the volcano . The Indonesian National Disaster Management Authority declared a 12 - kilometer exclusion zone around the volcano on 24 September . A plume was observed on 13 September . Evacuees gathered in sports halls and other community buildings around Klungkung , Karangasem , Buleleng , and other areas . The monitoring station is in Tembuku , Rendang , Karangasem Regency , where intensity and frequency of tremors were monitored for signs of the imminent large eruption . The area experienced 844 volcanic earthquakes on 25 September , and 300 to 400 earthquakes by midday on 26 September . Seismologists have been alarmed at the force and frequency of the incidents as it has taken much less for similar volcanoes to erupt . October ( edit ) In late October 2017 , the activity of the volcano decreased significantly , leading to lowering of the alert status on 29 October . The alert level remained at 3 ( out of 4 ) until the start of the second major activity period , and plumes were observed during this time . November ( edit ) 21 November ( edit ) There was a small phreatic eruption reported at 09 : 05 ( UTC ) , with the ash cloud top reaching 3,842 metres ( 12,605 ft ) above sea level . Thousands of people immediately fled the area , and over 29,000 temporary refugees were reported to be housed in over 270 locations nearby . 25 November ( edit ) A magmatic eruption began early on Saturday morning . The resulting eruption plume was reported to rise about 1.5 -- 4 km above the summit crater , drifting towards the south and dusting the surroundings with a thin layer of dark ash , leading some airlines to cancel flights bound for Australia and New Zealand . An orange glow was later observed around the crater at night , confirming that fresh magma had indeed reached the surface . 26 November ( edit ) At 23 : 37 ( UTC ) , another eruption occurred . Ngurah Rai International Airport was closed next day , leaving many tourists stranded . More than 100,000 people in a 10 - kilometre ( 6.2 mi ) radius of the volcano were ordered to evacuate . 27 November ( edit ) Ash plume from Mount Agung on 27 November Sunday 26 November 's eruption continued at a constant rate , and lahars were reported in the Selat district south of the volcano . The Australian Government 's Bureau of Meteorology reported that the top of the eruption column had reached an altitude of 9,144 m ( 5.7 miles ) . Ash continued to spread in a southeasterly direction , and estimates by the Pacific Disaster Center predicted that the resulting atmospheric ash exposure will affect up to 5.6 million people within the densely populated region surrounding the volcano . 29 November ( edit ) NASA MODIS aerial view of ash from Terra satellite . Reductions in eruption intensity and wind dispersal of the ash cloud led authorities to reopen Ngurah Rai International Airport at 07 : 00 ( UTC ) . Authorities also warned that the eruption volume could increase again at any time , potentially shutting down air traffic once more . Activity in 2018 ( edit ) January ( edit ) The volcano erupted once again on January 11 , sending plumes of smoke and ash , while Indonesia 's Bali international airport was declared safe , operating normally . The eruption column was reported to rise 2.5 km above the mountain . June ( edit ) Agung erupted on June 12 , sending plumes of smoke and ash some 2,000 meters above the volcano 's summit . No flights were affected from the event . On June 28 , water vapour and volcanic ash emission were detected from Mount Agung up to two kilometres into the air . The Ngurah Rai Airport was closed due to the event . July ( edit ) Agung erupted again July 3 due to a minor strombolian explosion . 700 people living near the crater were evacuated . No flights were affected . Impact ( edit ) The 2017 eruption caused some 40,000 people to be evacuated from 22 villages around Mount Agung . It also caused surrounding airports to be closed . Lombok International Airport , on the neighboring island of Lombok , closed on 26 November , but was reopened the next morning , only to be closed again on 30 November . Lombok 's airport reopened on 1 December . Ngurah Rai International Airport , located at the southern tip of the island and southwest of the volcano , closed on 27 November . More than 400 flights were canceled and about 59,000 passengers remained grounded . The airport was reopened on 29 November . This eruption also caused a decline in tourism on Bali by about 30 % . References ( edit ) Jump up ^ `` Agung '' . Global Volcanism Program . Smithsonian Institution . Retrieved 2018 - 01 - 23 . Jump up ^ MT AGUNG ACTIVITY REPORT `` Current indicators point to a relatively small eruption of VEI 2 ( volcanic eruptive index 2 ) '' Jump up ^ Anwari Dilmy . `` Pioneer Plants Found One Year After the 1963 Eruption of Agung in Bali '' / Pacific Science , Volume 19 , Number 4 , 1965 , p. 498 - 501 Jump up ^ Heinrich Zollinger . Eein uirsrapje naar her eiland Bali / Tijdschr . Neer . Ind . 74 : 43 , 1845 . ^ Jump up to : Zen , M.T. ; Hadikusumo , Djajadi ( December 1964 ) . `` Preliminary report on the 1963 eruption of Mt. Agung in Bali ( Indonesia ) '' . Bulletin of Volcanology. 27 : 269 -- 299 -- via Springer . ^ Jump up to : `` Mount Agung : Bali volcano alert raised to highest level '' . BBC News . 27 November 2017 . Retrieved 28 November 2017 . Jump up ^ `` Population of Indonesia by Province 1971 , 1980 , 1990 , 1995 , 2000 and 2010 '' . Badan Pusat Statistik ( in Indonesian ) . Archived from the original on 3 December 2017 . Retrieved 1 December 2017 . ^ Jump up to : Global Volcanism Program . Sennert , Sally Kuhn , ed . `` Report on Agung ( Indonesia ) '' . Weekly Volcanic Activity Report , 13 -- 19 September 2017 . Smithsonian Institution and US Geological Survey . Retrieved 28 November 2017 . Jump up ^ `` Indonesian official : More than 120,000 flee Bali volcano '' . Fox News . 28 September 2017 . Retrieved 28 September 2017 . Jump up ^ `` Thousands evacuated as Bali volcano sparks fear '' . The Australian . 24 September 2017 . Jump up ^ `` Mount Agung : facts about Bali 's imminent volcano eruption '' . UbudHood. 23 September 2017 . Retrieved 1 November 2017 . Jump up ^ `` How do experts know Mount Agung is about to erupt ? '' . ABC News Australia . 25 September 2017 . Retrieved 1 November 2017 . Jump up ^ Once tremors detected , Bali volcano can erupt within hours : Volcanologist CNA , 3 October 2017 Jump up ^ Lamb , Kate ( 26 September 2017 ) . `` Bali volcano eruption could be hours away after unprecedented seismic activity '' . The Guardian . ISSN 0261 - 3077 . Retrieved 26 September 2017 . Jump up ^ Topsfield , Jewel ; Rosa , Amilia ( 30 October 2017 ) . `` Mount Agung volcano alert in Bali downgraded '' . The Sydney Morning Herald . Retrieved 27 November 2017 . Jump up ^ Global Volcanism Program . Sennert , Sally Kuhn , ed . `` Report on Agung ( Indonesia ) '' . Weekly Volcanic Activity Report , 1 -- 7 November 2017 . Smithsonian Institution and US Geological Survey . Retrieved 28 November 2017 . Jump up ^ Global Volcanism Program . Sennert , Sally Kuhn , ed . `` Report on Agung ( Indonesia ) '' . Weekly Volcanic Activity Report , 8 -- 14 November 2017 . Smithsonian Institution and US Geological Survey . Retrieved 28 November 2017 . Jump up ^ `` VONA '' . Jump up ^ `` Bali 's Mount Agung volcano erupts '' . BBC News . 21 November 2017 . Retrieved 21 November 2017 . Jump up ^ Regular bulletins are posted on the website of the Indonesian National Disaster Management Agency . ^ Jump up to : `` Gunung Agung volcano ( Bali , Indonesia ) : eruption has begun '' . Volcano Discovery . 25 November 2017 . Retrieved 26 November 2017 . Jump up ^ `` ' Get out now ' 100,000 people told as Bali volcano continues to spew ash '' . Metro. 27 November 2017 . Retrieved 27 November 2017 . Jump up ^ `` A volcanologist explains Bali eruption photos '' . BBC News . 27 November 2017 . Retrieved 28 November 2017 . Jump up ^ Saifulbahri Ismail ( 27 November 2017 ) . `` Mount Agung eruption : Bali airport closed , flights cancelled '' . CNA . Retrieved 27 November 2017 . ^ Jump up to : `` Locals Watch As Lahars From Mount Agung Sweep Away Rice Fields '' . VIVA Indonesia ( in Indonesian ) . 27 November 2017 . Retrieved 27 November 2017 . Jump up ^ `` Mount Agung : Bali volcano alert raised to highest level '' . BBC News Online . Retrieved 27 November 2017 . ^ Jump up to : `` Life - saving technology provides alert as Bali 's Mount Agung spews ash , raises alarm '' . www.pdc.org . Archived from the original on 1 December 2017 . Retrieved 28 November 2017 . Jump up ^ `` Volcanic ash update for Mount Agung '' . Australian Government Bureau of Meteorology. 27 November 2017 . Retrieved 27 November 2017 . Jump up ^ `` Indonesia reopens Bali airport as wind clears volcanic ash '' . Reuters.com. 2017 - 11 - 29 . ^ Jump up to : `` Bali volcano : live updates on Mount Agung eruptions as airport reopens '' . Evening Standard . 2017 - 11 - 29 . Jump up ^ Volcano erupts in Indonesia 's Bali , airport remains safe Jump up ^ ( 1 ) Jump up ^ `` Bali volcano eruption : Mount Agung spews volcanic ash triggering CLOSURE of airport '' . Express Newspapers. 29 June 2018 . Retrieved 29 June 2018 . Jump up ^ `` Mount Agung : Bali flight chaos continues as more airlines cancel '' . The West Australian . 29 June 2018 . Retrieved 29 June 2018 . Jump up ^ `` 700 flee ' thunderous ' explosions and lava as Mount Agung erupts again '' . ABC News . 2018 - 07 - 03 . Retrieved 2018 - 07 - 04 . Jump up ^ `` Lombok International Airport closed due to volcanic ash from Mount Agung '' . Retrieved 29 November 2017 . Jump up ^ `` Bali volcano : State of emergency EXTENDED as Lombok airport closed over dangerous ash '' . Retrieved 30 November 2017 . Jump up ^ `` Bali airport remains closed for a third day '' . Retrieved 29 November 2017 . Jump up ^ `` Mount Agung : Bali Airport Closed And 59,000 Passengers Affected By Cancelled Flights '' . Retrieved 29 November 2017 . Retrieved from `` https://en.wikipedia.org/w/index.php?title=2017 -- 2018_eruptions_of_Mount_Agung&oldid = 860791018 '' Categories : 2017 in Indonesia 2017 natural disasters 2018 in Indonesia 2018 natural disasters 21st century in Bali 21st - century volcanic events Volcanism of Indonesia November 2017 events in Asia Hidden categories : CS1 Indonesian - language sources ( id ) Use dmy dates from November 2017 Wikipedia articles in need of updating from April 2018 All Wikipedia articles in need of updating Coordinates on Wikidata Articles containing potentially dated statements from November 2017 All articles containing potentially dated statements Talk Contents About Wikipedia Dansk Español हिन्दी Bahasa Indonesia Bahasa Melayu ଓଡ଼ିଆ Русский Simple English தமிழ் Українська Tiếng Việt 5 more Edit links This page was last edited on 23 September 2018 , at 02 : 44 ( UTC ) . Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply . 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Income elasticity of demand In economics , income elasticity of demand measures the responsiveness of the quantity demanded for a good or service to a change in the income of the people demanding the good . It is calculated as the ratio of the percentage change in quantity demanded to the percentage change in income . For example , if in response to a 10 % increase in income , the quantity demanded for a good increased by 20 % , the income elasticity of demand would be 20 % / 10 % = 2.0 Contents 1 Interpretation 2 Mathematical definition 3 Types of income elasticity of demand 4 Selected income elasticities 5 See also 6 Notes 7 References Interpretation ( edit ) Inferior goods ' demand falls as consumer income increases . A negative income elasticity of demand is associated with inferior goods ; an increase in income will lead to a fall in the demand and may lead to changes to more luxurious substitutes . A positive income elasticity of demand is associated with normal goods ; an increase in income will lead to a rise in demand . If income elasticity of demand of a commodity is less than 1 , it is a necessity good . If the elasticity of demand is greater than 1 , it is a luxury good or a superior good . A zero income elasticity of demand occurs when an increase in income is not associated with a change in the demand of a good . These would be sticky goods . Income elasticity of demand can be used as an indicator of industry health , future consumption patterns and as a guide to firms investment decisions . For example , the `` selected income elasticities '' below suggest that an increasing portion of consumer 's budgets will be devoted to purchasing automobiles and restaurant meals and a smaller share to tobacco and margarine . Income elasticities are closely related to the population income distribution and the fraction of the product 's sales attributable to buyers from different income brackets . Specifically when a buyer in a certain income bracket experiences an income increase , their purchase of a product changes to match that of individuals in their new income bracket . If the income share elasticity is defined as the negative percentage change in individuals given a percentage increase in income bracken the income - elasticity , after some computation , becomes the expected value of the income - share elasticity with respect to the income distribution of purchasers of the product . When the income distribution is described by a gamma distribution , the income elasticity is proportional to the percentage difference between the average income of the product 's buyers and the average income of the population . Mathematical definition ( edit ) ε Y = % change in demand % change in income ( \ displaystyle \ epsilon _ ( Y ) = ( \ frac ( \ % \ ( \ mbox ( change in demand ) ) ) ( \ % \ ( \ mbox ( change in income ) ) ) ) ) More formally , the income elasticity of demand , ε d ( \ displaystyle \ \ epsilon _ ( d ) ) , for a given Marshallian demand function Q ( I , P → ) ( \ displaystyle Q ( I , ( \ vec ( P ) ) ) ) for a good is ε d = ∂ Q ∂ I I Q ( \ displaystyle \ epsilon _ ( d ) = ( \ frac ( \ partial Q ) ( \ partial I ) ) ( \ frac ( I ) ( Q ) ) ) or alternatively : ε d = Y 1 + Y 2 Q 1 + Q 2 × Δ Q Δ Y ( \ displaystyle \ epsilon _ ( d ) = ( Y_ ( 1 ) + Y_ ( 2 ) \ over Q_ ( 1 ) + Q_ ( 2 ) ) \ times ( \ Delta Q \ over \ Delta Y ) ) This can be rewritten in the form : ε d = d ln  Q d ln  I ( \ displaystyle \ epsilon _ ( d ) = ( \ frac ( d \ ln Q ) ( d \ ln I ) ) ) With income I ( \ displaystyle I ) , and vector of prices P → ( \ displaystyle ( \ vec ( P ) ) ) . Many necessities have an income elasticity of demand between zero and one : expenditure on these goods may increase with income , but not as fast as income does , so the proportion of expenditure on these goods falls as income rises . This observation for food is known as Engel 's law . Types of income elasticity of demand ( edit ) There are five possible income demand curves : 1 . High income elasticity of demand : In this case increase in income is accompanied by relatively larger increase in quantity demanded . 2 . Unitary income elasticity of demand : In this case increase in income is accompanied by same proportionate increase in quantity demanded . 3 . Low income elasticity of demand : In this case increase in income is accompanied by less than proportionate increase in quantity demanded . 4 . Zero income elasticity of demand : This shows that quantity bought is constant regardless of changes in income . 5 . Negative income elasticity of demand : In this case increase in income is accompanied by decrease in quantity demanded . Selected income elasticities ( edit ) Automobiles 2.98 Books 1.44 A person 's own life ( also called Value of Statistical Life ) 0.50 to 0.60 Restaurant Meals 1.40 Tobacco 0.64 Margarine − 0.20 Public Transportation − 0.36 Income elasticities are notably stable over time and across countries due to the law of one price . See also ( edit ) Cross elasticity of demand ( CED ) Price elasticity of demand ( PED ) Price elasticity of supply ( PES ) Notes ( edit ) Jump up ^ Frank , Robert ( 2008 ) . p. 125 Jump up ^ Bordley and McDonald . Jump up ^ Samuelson ; Nordhaus ( 2001 ) . p. 94 . Jump up ^ WK Viscusi ( 2003 ) . `` The value of a statistical life : a critical review of market estimates throughout the world '' . Journal of risk and uncertainty . Jump up ^ Frank ( 2008 ) 125 . Jump up ^ Perloff , J. ( 2008 ) . p. 105 . References ( edit ) Bordley ; McDonald . `` Estimating Income Elasticities from the Average Income of a Product 's Buyers and the Population Income Distribution '' . Journal of Business and Economic Statistics . Perloff , J. ( 2008 ) . Microeconomics Theory & Applications with Calculus . Pearson . ISBN 978 - 0 - 321 - 27794 - 7 . Samuelson ; Nordhaus ( 2001 ) . Microeconomics ( 17th ed . ) . McGraw - Hill . Frank , Robert ( 2008 ) . Microeconomics and Behavior ( 7th ed . ) . McGraw - Hill . ISBN 978 - 0 - 07 - 126349 - 8 . Retrieved from `` https://en.wikipedia.org/w/index.php?title=Income_elasticity_of_demand&oldid=842246719 '' Categories : Demand Elasticity ( economics ) Talk Contents About Wikipedia Català Deutsch فارسی Bahasa Indonesia Magyar Nederlands Norsk Polski Português Русский Slovenčina Suomi Svenska 中文 5 more Edit links This page was last edited on 21 May 2018 , at 06 : 14 ( UTC ) . About Wikipedia