Observation of 2016 Kumamoto Earthquake by Pi-SAR-X2 and ...sarcv.ceos.org/site_media/media/documents/S23.2_Moriyama.pdf · Nagasaki University CEOS SAR CAL/VAL., 2016 Sept. 8 Observation

Nagasaki University CEOS SAR CAL/VAL., 2016 Sept. 8

Observation of 2016 Kumamoto Earthquake

by Pi-SAR-X2 and its polarimetric

calibration

1Toshifumi Moriyama, 2Yoshio Yamaguchi, 2Takanori

Ishikuro, 3Jyunpei Uemoto, 3Toshihiko Umehara, 3Akitsugu Nadai, 3Shoichiro Kojima

1, Graduate School of Engineering, Nagasaki University, Japan

2, Niigata University, Japan

3, Applied Electromagnetic Research Institute, National Institute of Information

and Communications Technology (NICT), Japan


• 2016 Kumamoto earthquake

• Emergency observation and response of 2016 Kumamoto

earthquake by various institutes and companies

• Japanese airborne X-band POLSAR “Pi-SAR2” and its

observation

• Polarimetric calibration of Pi-SAR2

• Results

• Conclusions

Outline


2016 Kumamoto earthquake

Land slides around Great Aso Bridge

(from google)

■April 14, 2016, 21:26 (JST)（Foreshock）：Epicenter： North-northwest of Kumamoto's city center

Depth ： 11km

Moment Magnitude Scale： :6.5

⇒The worst-hit area was in the eastern Kumamoto

suburb of Mashiki.

■April 16, 2016, 1:25 (JST)（Main shock after 28hours

of Foreshock)：Epicenter： Higashi Ward of Kumamoto City

Depth ：12km

Moment Magnitude Scale ：7.3

⇒Significant additional damage occurred in many areas

of Kumamoto Prefecture recovering from the April 14

earthquake

■Damage：Foreshock: 9 dead,

Mainshock: 41 dead

(Total: 50 dead, 1,684 injured）by Wikipedia

A location of Kumamoto, Japan


2016 Kumamoto earthquake

■The sequence of 2016 Kumamoto earthquakes:

(Fore) April 14, 21:26, Seismic intensity 7, Kumamoto area

April 14, 22:07, Seismic intensity 6, Kumamoto area


(Main) April 16, 1:25, Seismic intensity 7, Kumamoto area


April 16, 3:55, Seismic intensity 6, Aso area


■The number of times about eathquakes over Seismic intensity 4:

In April,


【Administrative agency】・JAXA->

The International Charter “Space and Major Disasters”

・The Geospatial Information Authority of Japan

【 Air Survey company】・Aero Asahi Corp.

・ Asia Air Survey Co., Ltd.

・Kokusai Kogyo Co., Ltd.

・PASCO Corp.

【Sales company of satellite data 】・JAPAN SPACE IMAGING CORPORATION

・Satellite Image Marketing Corporation

・Space Engineering Development Company

【National Institute, others】・ National Institute of Information and Communications

Technology (NICT)

・Remote Sensing Technology Center of Japan

Emergency observation and response of 2016 Kumamoto

earthquake by various institutes and companies・Providing a unified system of space

data acquisition and delivery to those

affected by natural or man-made

disasters

・Providing the aerial photographs and

the DinSAR results by PALSAR2.

・Providing the aerial photographs

by their own aircraft and the

satellite data by partnership with

foreign space agency.

・Providing the satellite data by

partnership with foreign space

agency.

・Providing POLSAR image by their

own sensor and the satellite data

and its analysis data by partnership

with JAXA.


Japanese airborne X-band POLSAR and its observation

Airborne Polarimetric Synthetic Aperture Radar (POLSAR)：

■ Observation of Pi-SAR2(NICT)

http://aer.nict.go.jp/institute/pdf/PiSAR2_J_Hi.pdf

Polarimetric observation

Interferometric observation


Pi-SAR2 equipped with jet (Gulfstream II) took off the prefectural Nagoya Airport around 7AM on April 17.

Pi-SAR2 arrived the damaged areas in Kumamoto Prefecture at 8:15AM.

Pi-SAR2 observed the area across Kumamoto Prefecture and Oita Prefecture from 8,700 meters above

sea level for 2 hours.






■ Observation of Pi-SAR2(NICT)（30cm resolution，there are data before and after

earthquake）

VV image

(False color:

before image

before image

after image)

Great Aso

Bridge

disappeared

after

eqarhquaek.



http://aer.nict.go.jp/institute/pdf/PiSAR2_J_Hi.pdf



Polarimetric observation




インターフェロメトリーデータ

y

x

Target 1

Target 2 Reference plane

H

VR

VR

HR

HR

polB

pol

0

0

H pol. ant.

V pol. ant.

V pol. ant

H pol. ant

Bpol=0.2ｍ

Polarimetric calibration of Pi-SAR2

Compensation of phase error caused by ground height among polarimetric channels：

Before compensation

Pauli decomposition image

(|SHH-SVV|，|SHV|，|SHH+SVV|)




Before compensation

Pauli decomposition image


Interferometry image


Phase error between HH and VV channels every observation campaign：

Makoto Satake, Jyunpei Uemoto, Takeshi Matsuoka, Tatsuharu Kobayashi, Shoichiro Kojima, Toshihiko Umehara,

Toshifumi Moriyama, "Polarimetric calibration of PI-SAR2: Experimental results of 2013 to 2015 observations",

Proceedings of 2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS) , pp.3655 - 3658, 2015



Before calibration After calibration

Pauli decomposition image observed on April 17）(|SHH-SVV|，|SHV|，|SHH+SVV|)




|HH| |HV| |VV|

flight

illu

min

atio

n

■ Arg(<Shh*Svv>)image（mgp data: 11ｘ11pixels）and Histogram of phase between HH and VV

0 500 1000 15002000 25003000 3500

0

500

1000

1500

2000

2500

3000

3500

az

gr

-150 -100 -50 0 50 100 150

0

25000

50000

75000

100000

125000

150000

175000

200000

225000

Phase [degree]

Pix

el num

ber

-27.75° -158.66°

186.41°

Phase error between HHとVV channels every observation campaign：



Aerial photograph distributed by GSI

（Observed on April 16）

Mashiki town in Kumamoto prefecture

Pi-SAR2 image of damaged areas

Pauli decomposition image observed

on April 17 (|SHH-SVV|，|SHV|，|SHH+SVV|)


Mashiki town in

Kumamoto prefecture

（Detection of an earthquake fault）

Aerial photograph distributed by GSI

（Observed on April 16）

Pauli decomposition image observed

on April 17




After earthquake 2016/04/17

(|SHH-SVV|，|SHV|，|SHH+SVV|)Google image

Central area of Kumamoto city





Before earthquake 2013/10/16






（Enlarged view of Kumamoto castle）












（Enlarged view of Kumamoto castle）



Image around

Great Aso Bridge








Image around

Great Aso Bridge


Polarimetric and Interferometric analysis methods

T Tk k THVVVHHVVHH SSSSS 22

1kCoherency matrix：

4componet decomposition technique (G4U)


Polarimetric data analysis






Pi-SAR2 Surface(%) Double(%) Volume(%)

Before 44.35 13.07 42.58

After 51.60 12.66 35.74



y

Target 1

Target 2Reference plane

H

MR

MR

SR

SR

B

0

0

Master ant.

Slave ant.

AL

x

■ Interferometry


Polarimetric and Interferometric analysis methods


Interferometric data analysis

After earthquake 2016/04/17Before earthquake 2013/10/16

Interferometry images around Great Aso Bridge before and after earthquake


No change（Green）

Blue

Black

Fa

lling

Ris

ing

Red

Yellow


DinSAR images around Great Aso Bridge bewteen Oct. 16 in 2013 and April 17, 2016


No change（Green）

Blue

Black

Fa

lling

Ris

ing

Red

Yellow


DinSAR images around Great Aso Bridge bewteen Oct. 16 in 2013 and April 17, 2016





Image around

Great Aso Bridge


Conclusions

By using Pi-SAR2 data, the areas damaged by 2016 Kumamoto earthquake

were confirmed. In order to investigate the data, the polarimetric and

interferometric analysis were used.

Due to high resolution（30cm）, the earthquake fault and the damage of

Kumamoto castle were confirmed.

By using G4U, it is confirmed that the surface scattering component are

increased and the volume scattering component are decreased in the land

slide areas.

Interferometric data shows that the forest areas falls due to land slides.


2016 Kumamoto earthquakes

■City lifeline(Electricity, City gas, Water, Kyusyu Shinkansen)

1) Electricity

On April 20, the electricity was provided to most homes and

factories except for the areas being closed down to traffic.

2) City gas

On April 30, the city gas service was recovered in

Kumamoto city.

3) Water

On April 30, the water was provided to most homes in

Kumamoto city.

4) Kyushu Shinkan-sen

On April 28, Kyushu Shinkansen was recovered.


Polarimetric analysis

Rough

surface

Rough

surface

HH HV=VH VV

HH HV

VH VV

S SS HV

S S

2 * *

2* *

2* *

2

2 2 2

2

HH HH HV HH VV

HV HH HV HV VV

VV HH VV HV VV

C HV

S S S S S

S S S S S

S S S S S

hv hv hv

s d vsurface double volumeC HV f C f C f C

Scattering matrix

Averaged covariance matrix

, ,s d vf f f : Features in region of interest

Polarimetric images

Double

bounce

Double

bounce Canopy

Layer

Canopy

Layer

Polarimetric decomposition

technique, Entropy/Alpha analysis

Transformation, Averaging


Satellite data ：DinSAR results by using ALOS2/PALSAR2 data were introduced by GSI JAPAN.

(a) Phase image

Between March 7 and April 18 in 2016

(b) Phase image

Between April 17 and May 1 in 2016

http://www.gsi.go.jp/BOUSAI/H27-kumamoto-earthquake-index.html#3


earthquakes by various institutes and companies

Nagasaki University CEOS SAR CAL/VAL., 2016 Sept. 8http://www.gsi.go.jp/common/000140103.jpg

Aerial photograph ：Aerial photograph were introduced by GSI JAPAN.


earthquakes by various institutes and companies


Image around

Great Aso Bridge





Spaceborne POLSAR ALOS/PALSAR

May 24, 2014


December 3, 2015 (Before earthquake：6m resolution)

area1

area2

area3


area1

area2

area3

一般的に：市内は紫，森林は緑，耕作地は青で表示されます．

April 21, 2016 (after earthquake：6m resolution)


Area3: Around Mt. Aso



After earthquake：White areas

are increased.

Area3: Around Mt. Aso




Area2: Around Great Aso Bridge



Area2: Around Great Aso Bridge

After earthquake：Land slides

are detected.





After earthquake：Red areas

are increased.

After earthquake：Red areas

are decreased.


Pi-SAR-X2でのデータ補正その１

■ 偏波観測について

y

x

Target 1


H

VR

VR

HR

HR

polB

pol

0

0

H pol. ant.

V pol. ant.

V pol. ant

H pol. ant

Bpol=0.2ｍ

■V pol. antとH pol. ant間の位相差

■ V pol. antとH pol. ant間の位相差（Flat earth phase）

(1’)

(2’)

⇒ (2’)-(1’):Flat earth phase removing

(0 is unknown)

0 0 0

2cosV H pol polafter flat earth

B

0

2sin 1V H pol polB on target

0

2sin 2V H pol polB on target

Multi-look Ground-range Polarimetry data(MGP):

,

exp ,

HH HH

HV HV after flat earthHV

Z S

Z S j

exp ,

exp 2

VH VH after flat earth

VV VV after flat e

V H

thH rV a

Z S j

Z S j

ポラリメトリのデータにインタフェロメトリーのデータが残っている


y

Target 1

Target 2Reference plane

H

MR

MR

SR

SR

B

0

0

Master ant.

Slave ant.

AL

x

y

x

Target 1


H

VR

VR

HR

HR

polB

pol

0

0

H pol. ant.

V pol. ant.■ インターフェロメトリー観測について ■ 偏波観測について

0

0

cos

cos

pol pol

V H M Safter flat earth after flat earth

B

B

⇒ (2’)-(1’):Flat earth phase removing

(0 is unknown)

0 0 0

2cosV H pol polafter flat earth

B

⇒ (2)-(1):Flat earth phase removing

(0 is unknown)

0 0 0

2cosM S after flat earth

B

Pi-SAR-X2でのデータ補正その１

Documents

Observation of 2016 Kumamoto Earthquake by Pi-SAR-X2 and ...sarcv.ceos.org/site_media/media/documents/S23.2_Moriyama.pdf · Nagasaki University CEOS SAR CAL/VAL., 2016 Sept. 8 Observation