CONTRIBUTION OF MOUNT MERAPI CONTRIBUTION OF MOUNT MERAPI VOLCANO EMISSION VOLCANO EMISSION

DURING QUIESCENT STATE TO DURING QUIESCENT STATE TO BACKGROUND SOBACKGROUND SO22 CONCENTRATION CONCENTRATION

IN D.I. YOGYAKARTA PROVINCEIN D.I. YOGYAKARTA PROVINCE

CONTRIBUTION OF MOUNT MERAPI CONTRIBUTION OF MOUNT MERAPI VOLCANO EMISSION VOLCANO EMISSION

DURING QUIESCENT STATE TO DURING QUIESCENT STATE TO BACKGROUND SOBACKGROUND SO22 CONCENTRATION CONCENTRATION

IN D.I. YOGYAKARTA PROVINCEIN D.I. YOGYAKARTA PROVINCE

Regina Dhevita PurieRegina Dhevita Purie and Driejana and Driejana Faculty of Civil and Environmental Faculty of Civil and Environmental Engineering, Engineering, Institut Teknologi Bandung, IndonesiaInstitut Teknologi Bandung, Indonesia

BAQ, December 2006

Background

• SO2 emission from Merapi volcano might contribute to SO2 ambient air concentration in the surrounding area

• Volcanic emission during quiescent state might have impact to environment, however monitoring to emission and its impacts have not got much attention

Objectives• To examine the spatial distribution

of SO2 from Mt. Merapi during normal activity within the volcano surrounding area

• To observe its potential impact to the environment

Boundary conditions

• The point source emission is assumed to be continuous

• The dispersion prediction is carried out within an area of 13.5 km X 13.5 km surrounding Merapi including Kabupaten Magelang, Kabupaten Boyolali, Kabupaten Klaten in Central Java and Kabupaten Sleman in DI Yogyakarta

Methodology• Collecting primary data from Volcanology Agency

for emission data (Q) and plume rise (∆h) from COSPEC measurement in 2002, wind speed, wind direction and atmospheric stability from the Met Office, and topographical data such as the height of mountain and the altitude of receptor area

• Modeling based on Gaussian Plume Model for daily average concentration during dry season period (April – September)

• Ambient air sampling of SO2 to validate the model• Observing the evidence of SO2 impact to

surrounding area of Mt.Merapi

Mt. Merapi

DIY

Magelang

Boyolali

Klaten Study Area

Results and discussion• The prevailing winds were from

south, southwestern and southeastern directions

• The daily dispersion patterns are found to be similar

• Six days (a day in every month) are taken as the examples for the predicted dispersion pattern

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Contoh Pola Dispersi pada tanggal 5 April

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Contoh Pola Dispersi pada Tanggal 23 Mei

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Contoh Pola Dispersi pada Tanggal 7 Juni

Kab. Boyolali

Kab. Boyolali

Kab. Boyolali

Kab. Magelang

Kab. Magelang

Kab. Magelang

Kab. Klaten

Kab. Klaten

Kab. Klaten

DIY DIY DIY

April 5th May 23th

June 7th

Mt. MerapiDate Atm Stb

Wind speed (ms-

1)

Plume rise (m)

Emission (g.s-1)

April 5th A 1 50 1,250.00

May 23th A 1 96 1,793.98

June 7th A 0.5 325 1,932.87

SO2 unit of concentration: µg.m-3

The dispersion pattern of SO2

Date Atm StbWind speed

(ms-1)

Plume rise (m)

Emission (g.s-1)

July 12th A 1.5 375 983.796

August 13th

A 2 611,041.66

7

September 15

th A 2 75 717.593

Mt. Merapi

Unit concentration of SO2: µg.m-3

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Contoh Pola Dispersi pada 12 Juli

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Contoh Pola Dispersi pada 13 Agustus

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Contoh Pola Dispersi pada 15 September

Kab. Boyolali

Kab. Boyolali

Kab. Boyolali

Kab. Magelang

Kab. Magelang

Kab. Magelang

Kab. Klaten

Kab. Klaten

Kab. Klaten

DIY DIY DIY

July 12th

Agst 13th

Sept 15th

The dispersion pattern of SO2

•The average concentration of SO2 from April to September 2002 was 23.09 µg.m-

3 ,with the maximum daily concentration SO2 of 490.72 µg.m-3 and the minimum daily concentration of 2.77 µg.m-3

•The maximum concentrations mostly fall within the distance of 0.6 – 3.4 km from the center of the volcano

Receptor points

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Kab. Boyolali

Kab. Klaten

Kab. Sleman, DIY

Kab. Magelang

Mt. Merapi

The areas where SO2 deposition are most likely to happen

The damage of plantation, such as cabbage, tobacco, tea, and the root of tobacco plant

colourosis

Necrosis & colourosis

colourosis

Visible indication of the SO2

impacts to plantation

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Tobacco plantation at Dusun Jerakah (438.138,36; 9.170.352,19; 1291,5)

Soil Condision at Dusun Jerakah(438.138,36; 9.170.352,19; 1291,5)

The impact SO2 to soil and tobacco plant

• Inventory emission from volcano is necessary, not only for the purpose of monitoring the volcanic activity, but also for mitigation of the emission impact

• The locations of maximum concentration were found to be at the same grid locations, covering an area of about 400 to 800 hectares on the distance of 0.6 – 3.4 km in the north-eastern, northern and western of Mount Merapi.

• The maximum concentrations of SO2 were found in Kabupaten Magelang, Kabupaten Boyolali and a little part of Kabupaten Klaten area. According to the land use, these areas can be considered as ecological sensitive area.

Conclusions and Conclusions and RecommendationRecommendation

• Indications of environmental impact caused by volcanic emission of Merapi have been seen, particularly on plantation and the form of soil.

• Specific mitigation plans therefore might need to be developed for this area, to reduce the impacts to the minimal.

Thank You!