研究紹介Research introductions

Chiba University

千葉大学大学院自然科学研究科像科学専攻Graduate School of Science and Technology, Chiba University

ヨサファット テトォコ スリ スマンティヨJosaphat Tetuko Sri Sumantyo

Sumatera island

Java island

Lampung bay

Legundi island

Sertung island

Panaitan island

Sunda

stra

it

Krakatau volcano

complex

Panjang island

Rakata island

0 15 km

N

Situation map

Banten

Lampung

クラカトア山島群

Indonesia

Volcanoes in Indonesia : 129 volcanoesSumatera : 12 Java : 21 Bali : 2 Nusa Tenggara : 20 Banda sea : 9 North Sulawesi : 6 Sangihe : 5 Halmahera : 5 Krakatau volcano complex (ESDM, Indonesia)

SAR mosaic

ancient Krakatau 60,000 years ago

after gigantic eruption with the lost of volcano dome in 60,000 years ago

Rakata

Panjang

Sertung

caldera before 1883

Rakata

Panjang

sertung

Danan

Perbuwatan

growing up of Rakata, Danan and Perbuwatan volcanoes 17th century

Rakata

Panjang

Sertung

caldera after 1883

paroxymal explotion of Danan and Perbuwatan volcanoes on August 27, 1883 → 36,417 people killed and swept 295 villages

Rakata

Sertung

DananPerbuwatan

Panjang

Rakata, Danan and Perbuwatan volcanoes activities stopped in 1681.

Rakata

Panjang

Sertung

Anak krakatau

Krakatau volcano complex growing slowly nowadays and always create spectacular history …

歴史：クラカトア山島群の誕生

North

① ② ③

④ ⑤ ⑥

0

50

100

150

200

250

300

350

1930 1952 1953 1968 1973 1983 1996

Observation year

Hei

ght [

met

er a

sl] Anak Krakatau

Photographs : ESDM, Indonesia

歴史：クラカトア山島群の誕生

rotated image

North

合成開口レーダ画像生成過程

range compressed image

azimuth compressed image

raw data

sensor illumination

Range

Azim

uth

JERS-1 satellite

No

rth

Full scene of JERS-1 SAR 19980731

Anak Krakatau island

Panjang island

Rakata island

Sertung island

Subset of JERS-1 SAR 19980731

North

North

合成開口レーダ画像生成過程

Landsat TM 19920518

Anak Krakatau island

Panjang island

Rakata island

Sertung island

JERS-1 SAR 19980731

N

N

Panjang islandSertung island

Anak Krakatau island

Rakata island

Map legend

Lav Lavas in 1963, 1972, 1975, 1980

Pca1 Pyroclastic airfall layer of ash, scoriaeous lapilli, sand exposed in 1982.

Pca2 Pyroclastic airfall layer of ash, scoreae, lapilli, sand exposed in 1956.

Smd Material deposit of the rock such as silt, sand or block size, andesites, basaltic andesite, and obsidian fragments

Hal Hyperstene augite andesite lava

Pf 1883 Pyroclastic flow

Bal Basaltic lava

Roc1 Rock distribution

Roc2 Estimated rock distribution

クラカトア山島群地質図とＳＡＲ画像の関係

Landsat TM 19920518

Anak Krakatau island

Panjang island

Rakata island

Sertung island

JERS-1 SAR 19980731

N N

Panjang islandSertung island

Anak Krakatau island

Rakata island

Geological cross section

クラカトア山島群地質図とＳＡＲ画像の関係

North

0 2 km composited SAR images

19941105

19961122

19980913

19941105

19961122

19980913

クラカトア火山活動

0 50 100-20

-15

-10

-5

0

sigm

a-nu

ll o [

dB]

1994 1996 1998

A B

A

Sea level

Pre-historic Krakatau

Rakata island

Pre-1883 Kraka

tau

Sertung island

Pf 1883Hal

Hal

Bal

Pf 1883

2000m

1500m

1000m

500m

0m

A B

B

後方散乱係数の見方

Sea level

Anak Krakatau islandPanjang island

Pf 1883

Hal

Pre-historic Krakatau

Sea level

Hal Pf 1883

SmdPca2Pca2Lav 1972/1973Pca1

1000m

750m

500m

250m

0m

C D

Pre-h

istor

ic Kra

kata

u

Sertung island

0 50 100-20

-15

-10

-5

0

sigm

a-nu

ll

o [dB

]

1994 1996 1998

C D

C

D

後方散乱係数の見方

Pf 1883

1000m

750m

500m

250m

0m

E F

Anak Krakatau islandPanjang island

Pre-historic Krakatau

Sea level

HalPca2Pca2Lav 1972/1973 Pca1

Smd

0 50 100-20

-15

-10

-5

0

sigm

a-nu

ll

o [dB

]

1994 1996 1998

E F

E

F 後方散乱係数の見方

-20

-15

-10

-5

0 1994 1996 1998

sigm

a-nu

ll

o [dB

]

#1

19941105

19961122

19980913

4 dB5 dB

後方散乱係数と火山活動の関係

-20

-15

-10

-5

0 1994 1996 1998

sigm

a-nu

ll

o [dB

]

#2

19941105

19961122

19980913

後方散乱係数と火山活動の関係

-20

-15

-10

-5

0 1994 1996 1998

sigm

a-nu

ll

o [dB

]

#3

7 dB5 dB

19941105

19961122

19980913

後方散乱係数と火山活動の関係

-20

-15

-10

-5

0 1994 1996 1998

sigm

a-nu

ll

o [dB

]

#4

19941105

19961122

19980913

5 dB3 dB

後方散乱係数と火山活動の関係

Pf 1883 -8 dB

Pca1 -10 dB

Pca2 -6 dB

Lav 1972/1973 -10 dB

Hal -12 dB

Smd -9 dB

Sea surface -16 dB

Backscattering coefficient of each soil type

Radar respons / backscattering coefficient of new lava around Anak Krakatau Volcano

Northern area : 5 ~ 7 dB increased

Western area : 4 ~ 5 dB increased

North-eastern area : 3 ~ 5 dB increased

後方散乱係数と火山活動の関係