SAR Detection of - - PowerPoint PPT Presentation

▶
sar detection of landslides triggered by the 2007 noto
SMART_READER_LITE
LIVE PREVIEW

SAR Detection of - - PowerPoint PPT Presentation

Jan 30, 2024 304 likes •546 views

SAR Detection of landslides triggered by the 2007 Noto Hanto Earthquake using SAR interferometry

slide-1
SLIDE 1

SAR干渉解析による能登半島地震に伴う 地すべり変動の抽出

Detection of landslides triggered by the 2007 Noto Hanto Earthquake using SAR interferometry

矢来博司・飛田幹男・宇根寛・佐藤浩 （国土地理院）

  • H. Yarai, M. Tobita, H. Une, H. Sato (Geographical Survey Institute)
slide-2
SLIDE 2

The 2007 Noto Hanto Earthquake

  • March 25, 2007
  • Mjma 6.9
  • JMA seismic scale 6+
  • Crustal deformation

detected by GPS, Insar and leveling

(from DPRI website)

slide-3
SLIDE 3

ALOS/PALSAR interferograms

Ascending41.5°

2007/02/23-2007/04/01

Descending34.3°

2006/12/23-2007/05/10

衛 星 視 線 方 向 衛星飛行方向 衛 星 視 線 方 向 衛星飛行方向

☆ ☆

2007/03/25 M6.9

slide-4
SLIDE 4

LOS displacement

Contour : 10cm Contour : 10cm

slide-5
SLIDE 5

depth：1.1km depth：18.9km

A fault model inverted from GPS and InSAR

Ozawa et al. (2007)

slide-6
SLIDE 6

Interferogram Simulated image

Ascending 41.5° Descending 34.3°

slide-7
SLIDE 7

Interferogram shows …

Coseismic deformation due to fault dislocation

＋

Several local phase change area (100m – a few km) ・DEM error ? ・Real displacement ?

slide-8
SLIDE 8

What is the “local phase change”?

Descending 34.3°

2006/12/23-2007/05/10 Bperp = 219m

Ascending 41.5°

2007/02/23-2007/04/01 Bperp = 446m

slide-9
SLIDE 9

What is the “local phase change”?

Descending34.3°

2006/12/23-2007/05/10 Bperp = 219m

Descending34.3°

2007/05/10-2007/08/10 Bperp = 491m

Coseismic Postseismic Possibly local movements

  • f land surface due to the

Noto Hanto EQ

slide-10
SLIDE 10

Residual image

Local movements of land surface (such as landslide)

＝

Interferogram

Crustal deformation due to the EQ

ー

slide-11
SLIDE 11
  • 震源域近傍で多数発生
  • 長さ・幅数100m程度の

楕円形や馬蹄形

  • 多くが地すべり地形の

全体あるいはその一部 で発生

  • 変位量は数cm～20cm

程度

  • 推定される変動の向き

は概ね地形と整合的

（内部の沈下もしくは最大傾斜 方向への水平移動）

5km

Residual image with landslides distribution map

slide-12
SLIDE 12

比較拡大図

3km

slide-13
SLIDE 13

Field survey

5km

A B C

A, B: Phase change area is consistent with landslide block. C: Phase change area is not consistent with landslide block.

slide-14
SLIDE 14
  • A. （門前町俊兼）
slide-15
SLIDE 15
  • B. （門前町大生）
slide-16
SLIDE 16
  • C. （中島町古江）
  • Deformation area is not

consistent with landslide area

  • No evidence of landslide

recognized at this area.

slide-17
SLIDE 17

2-D displacement calculation

２つの方向からの観測を合成することで 変動を２次元で検出できる Descending Ascending

slide-18
SLIDE 18

Quasi E-W Quasi U-D

2-D displacement

slide-19
SLIDE 19

2-D residual displacement

Residual Quasi E-W Residual Quasi U-D

slide-20
SLIDE 20

2-D residual displacement

Residual Quasi U-D Residual Quasi E-W

contour：1cm

Residual image (A41.5)

But, typical landslide deformation.

Deformation area is not consistent with landslide block.

slide-21
SLIDE 21

Rotational slip estimation

Quasi-UD Quasi-EW

Estimated slip surface depth : 200m Such movement can be considered as the sign

  • f the initial process of the development of

large landslides.

slide-22
SLIDE 22

Conclusion

  • ALOS/PALSAR interferogram of the 2007 Noto

Hanto earthquake includes not only crustal deformation derived from EQ but also local surface deformation, such as landslide.

  • We can detect the local deformation such as

landslide derived from earthquake by subtracting from interferogram to deformation due to earthquake.

  • InSAR is a powerful tool for not only geophysics

but also geography, disaster prevention.

slide-23
SLIDE 23

謝辞

  • 本研究で用いたALOS/PALSARデータは、国土

地理院とJAXAとの間の共同研究協定に基づい て提供された。また、ALOS/PALSARデータの所 有権は、JAXA及びMETIが所持する。