Integration of GPS and InSAR data in Japan

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Integration of GPS and InSAR data in Japan
Kobe City
FUJIWARA, Satoshi Geographical Survey Institute,
Japan
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Outline

• GPS stations array in Japan
• InSAR (Synthetic Aperture Radar
  interferometry)
• Merits and Demerits
• GPS vs. InSAR
• Integration of GPS and InSAR

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GPS Stations in Japan
1224 stationsthroughoutJapan
Average spacing between stations20 km
GEONET GPS Earth Observation NETwork
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GPS Station
GPS Antenna

• Receives GPS signals continuously

• Transfers Data every 1 second via IP Network

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Displacement Vector Map form Oct. 2003 to Oct.
2004

• Plate motion
• Local events
• Earthquakes
• Volcanic activities

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Displacement Vector Map of 2004 Chuetsu
Earthquake(M6.8)
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Time series of Displacement by GPS
M6.1
M6.8
M5.2
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Seismic wave in Japan of 2004 Sumatra Earthquake
GPS
North(mm)
Seismometer
10min
GPS
East(mm)
Seismometer
GPS
Up(mm)
Seismometer
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Monitoring displacement from space
Earthquake
Subsidence
Volcano
Landslide
4km
Unknown
Landslide
Known
Kobe
Usu volcano
Lake Towada
TOKYO
JERS-1 SAR Interferometry
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1995 Kobe Earthquake (M7.3)
20km
Sep. 1992 Feb. 1995 JERS-1 SAR
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Horizontal gradient of displacement and small
surface faultsfound by InSAR
1995 Kobe Earthquake
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Landslide
Birds-eye-view
Mt Onnebetsu-dake Northern Japan
Sep. 1994 Aug. 1995 JERS-1 InSAR
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InSAR vs. GPS for monitoring surface displacement

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2D Displacement Vectors by InSAR
1998 Mt Iwate Earthquake (M6.1)
Combining Ascending and Descending InSAR images
2D displacement on 2D plane
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Error and Horizontal Scale
Atmospheric Noise
Decorrelation
InSAR
GPS (Up-Down)
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Differential Atmospheric Delay in InSAR image
Mt Fuji
warm and wet region
Volcanic Inflation
Izu peninsula, central Japan
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Subsidence
Jan. 1995 Mar. 1998 JERS-1 InSAR
Known subsidence by leveling
Unknown subsidence
TOKYO
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Leveling vs. InSARGPS

• GPS makes InSAR accurate.

Tobita, et al., 2004
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Leveling vs. InSARGPS
Tobita, et al., 2004
Down
Up
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Volcanic Deformation
Lake Kussharo
Atosanupuri Volcano
Aug. 1993 April 1995 JERS-1 InSAR
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Inflation
Deflation
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Volcanic Deformation
Deflation
Inflation
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Installing New GPS station
NEW GPS station
Aug. 1993 April 1995 JERS-1 InSAR
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1997 Kagoshima Earthquake (M6.1)
Mar. 1997 April 1997 JERS-1 InSAR
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2005 Fukuoka Earthquake (M7.0)
ENVISAT(esa)
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From JERS-1 to ALOS
JERS-1 Feb. 1992 Oct. 1998
ALOS September 2005 -
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2004 Sumatra EarthquakeCoastal Change Inferred
from SAR
Derivation of Coastal Changes using Two Radar
Backscatter Intensity Images
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2005 Sumatra Earthquake (after shock)Coastal
Change Inferred from SAR
Derivation of Coastal Changes using Two Radar
Backscatter Intensity Images
http//cais.gsi.go.jp/Research/topics/topic041226/
index_e.html
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2004 Sumatra EarthquakeCoastal Change Inferred
from SAR
Derivation of Coastal Changes using Two Radar
Backscatter Intensity Images
Before the Earthquake
After the Earthquake
Northern Sumatra Island (RADARSAT)
North Sentinel island (ENVISAT)
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Derivation of Coastal Changes using Two Radar
Backscatter Intensity Images
Before earthquakeRadar image
After earthquakeRadar image
Comparison imageCoastal change
An area colored in red in the image left is a
region where the reflective (backscatter)
intensity is decreased due to submergence and
Tsunami inundation.
An area colored in blue in the image left is a
region where the reflective (backscatter)
intensity is increased due to uplift.
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Conclusion

• InSAR monitors displacement in a wide area but
  not accurate for all data.
• GPS monitors accurate time series.
• GPS makes InSAR accurate.
• New GPS site selection by InSAR.
• We are looking forward to ALOS.

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Kobe City
Thank you for your attention.