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Table 1 Interferograms used to estimate the 3-D deformation

From: Precursory ground deformation of the 2018 phreatic eruption on Iwo-Yama volcano, revealed by four-dimensional joint analysis of airborne and spaceborne InSAR

Orbit

Time period

RADAR

Bperp (m)

\(\theta_{\text{i}}\) (deg.)1

\(\theta_{\text{h}}\) (deg)2

R/L3

\(\sigma\) (cm)4

3-D deformation estimate

 EW

Aug. 07, 2014–Aug. 04, 2016

Pi-SAR-L2

− 0.6

54

301

L

0.22

 EW

Aug. 04, 2016–Sep. 06, 2017

Pi-SAR-L2

− 5.9

54

301

L

0.66

 NS

Aug. 07, 2014–Aug. 04, 2016

Pi-SAR-L2

− 6.2

45

208

L

0.34

 NS

Aug. 04, 2016–Sep. 06, 2017

Pi-SAR-L2

7.6

45

208

L

0.94

 SN

Aug. 07, 2014–Aug. 04, 2016

Pi-SAR-L2

− 4.1

61

28

L

0.64

 SN

Aug. 04, 2016–Sep. 06, 2017

Pi-SAR-L2

− 1.6

61

28

L

0.22

 131-260

Sep. 30, 2014–Jul. 19, 2016

PALSAR-2

− 134

43

350

R

0.30

 131-260

Jul. 19, 2016–Oct. 10, 2017

PALSAR-2

80

43

350

R

0.33

 23-2790

Feb. 09, 2015–Aug. 08, 2016

PALSAR-2

− 144

36

190

R

0.42

 23-2790

Aug. 08, 2016–Sep. 18, 2017

PALSAR-2

− 80

36

190

R

0.37

2.5-D deformation estimate

 131-260

Oct. 10, 2017–Apr. 10, 2018

PALSAR-2

—145

43

350

R

–

 23-2970

Sep. 18, 2017–Apr. 16, 2018

PALSAR-2

241

36

190

R

–

  1. 1Incidence angles \(\left( {\theta_{\text{i}} } \right)\) at Iwo-yama
  2. 2Heading angles (\(\theta_{\text{h}}\)) are defined as clockwise angles from the north
  3. 3R and L indicate right or left looking, respectively
  4. 4\(\sigma\) indicates phase variance in each interferogram, which is used to weight the observation to delineate the 3D deformation