IGARSS2011_aster_volcano_urai.ppt
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Transcript of IGARSS2011_aster_volcano_urai.ppt
Volcano observations with ASTER and ASTER image database for
volcanoes
Urai, Minoru
Geological Survey of Japan, AIST
Topics• Introduction• Overview of ASTER instruments• Volcano monitoring with ASTER
– Volcanic gas monitoring : Miyake-jima, Japan– Caldera collapse and lava flow : Piton de la Fournaise
• ASTER image database for volcanoes• Conclusions
IntroductionResent volcanic hazard– Eyjafjallajokull 2010 : Over 100,000 flights cancelled
– Merapi 2006 : 17,000 people were evacuated
– Two people were killed by a pyroclasic flow
– Pinatubo 1991 : Up to 800 people were killed
– In 1992 and 1993, the average temperature in the Northern Hemisphere was reduced 0.5 to 0.6°C
Historic volcanic hazard– Tambora 1815 : 92,000 people were killed
– Unzen 1792 : 15,000 people were killed
IntroductionASTER can be used for volcano observations
(1)Topographic and geologic analysis,
(2)Mapping volcanic products,
(3)Eruption plume analysis,
(4)Discolored sea water and crater lake monitoring,
(5)Generating digital elevation models,
(6)Surface temperature mapping,
Overview of ASTERLaunch date 18DEC1999Platform Terra satelliteOrbit 16days polar orbitObservation time 10:30AMData recorder yes
Subsystems VNIR, SWIR,TIRStereo function yesTotal bands 14+1Swath width 60kmLifetime 6 years
Acquired scene Over 1,800,000 scenes
Overview of ASTER•ASTER has nadir (3N) and backward (3B) looking views.
•3N and 3B compose a stereoscopic pair.
•A DEM can be generated from the stereoscopic pair.
•However, DEM can not be generated cloud covered area and a DEM covers 60 km by 60 km.
ASTER stereo image function.(http://www.ersdac.or.jp/GDEM/E/2.html)
0
0.2
0.4
0.6
0.8
8 9 10 11 12
SO2 0g/m2
SO2 10g/m2
Wavelength
Miyake-jima is located about 180km south of TokyoSO2-rich plume absorb thermal emission from sea at 8.6µm Cyan color indicates that temperature derived from band 11 is lower than others
ASTER TIR RGB : 11, 13, 14On November 8, 2000
Volcanic gas monitoring : Miyake-jima, Japan
Volcanic gas monitoring : Miyake-jima, Japan
No Height
(m)
Wind velocity
(m/s)
Wind direction (degree*)
1 286 9.0 305
2 765 11.7 296 3 794 12.5 298
Plume heights, wind velocities and directions estimated from ASTER
Nadir viewing image
Backward viewing image
Volcanic gas monitoring : Miyake-jima, Japan
ASTER TIR
MODTRAN
2D- SO2 distribution
MODTRAN
Plume height
SO2 flux estimation
ASTER stereo pair
Wind velocity
Atmospheric profile
Plume height and wind velocity analysis
Sea surface temperature
SO2 flux
B13 B11
Volcanic gas monitoring : Miyake-jima, Japan
The estimation of two-dimensional SO2 distribution
Volcanic gas monitoring : Miyake-jima, Japan
Measurement
line
Measurement
time
Wind speed
[m-s]
SO2 flux
[t day-1]
L1 – L1’ 11:44 – 11:53 8 3.22 x104
L2 – L2’ 11:55 – 12:07 8 3.09 x104
L3 – L3’ 12:18 – 12:29 8 2.67 x104
SO2 flux measured by COSPEC
Distance from the vent (km)
SO2
flux
(to
n/da
y)
The estimation of SO2 flux
thC
h CdsQ sin
α = 7 1 ° V h = 1 1 .1 m /s
0
1 104
2 104
3 104
4 104
5 104
6 104
7 104
0 5 10 15 20 25
Caldera collapse and lava flow : Piton de la Fournaise
• Piton de la Fournaise is one of the most active volcanoes located on the French island of Reunion in the western Indian Ocean.
• There are three calderas that were formed by progressive eastward slumping of the volcano.
Caldera collapse and lava flow : Piton de la Fournaise
On April 2, 2007, a new 1 km long vent opened at 650 m altitude in the southern part of Grand Brule. The lava flows reached the sea.
On April 5 to 6 and over the whole following day, the summit (Dolomieu) crater floor collapsed.
ASTER VNIR image taken on June 8, 2005
Caldera collapse and lava flow : Piton de la Fournaise
October 31, 2006
April 17, 2007
Caldera collapse and lava flow : Piton de la Fournaise
May 6, 2007 (after eruption) June 8, 2005 (before eruption)
VNIR images with 100 m contour
Caldera collapse and lava flow : Piton de la Fournaise
ASTER DEM differenceE-W ASTER DEM profile
Depression : 320 m at mostTotal volume : 9.6 107 m3
Caldera collapse and lava flow : Piton de la Fournaise
New lava deposit area : 3.85 km2
Surface temperature distribution derived from ASTER nighttime observed on May 4, 2007 superimposed on
ASTER daytime image observed on June 8, 2005
ASTER image database for volcanoes
△ Rank A (104)△ Rank B (220)△ Rank C (640)Volcanoes monitored by ASTER
Global volcano monitoring plan with ASTER
ASTER image database for volcanoes
Google Earth Version of ASTER image database for volcanoes athttp://igg01.gsj.jp/vsidb/image/vsidb.kml
ASTER image database for volcanoes
Full resolution display of ASTER image database for volcanoes
ConclusionsThe ASTER’s ability to monitor volcanic activities, such as thermal anomalies, topographic changes, volcanic gases, among others, has been validated.
A web-based ASTER Image Database Volcanoes is opened to the public (http://igg01.gsj.jp/vsidb/image/index-E.html). The database contains all ASTER images of 964 active volcanoes.