The 2019 White Island Volcano Eruption, New Zealand

A large eruption occurred at White Island volcano in New Zealand on December 9, 2019 (UTC). We analyzed Synthetic Aperture Radar (SAR) data of ALOS-2/PALSAR-2 to investigate the ground surface changes associated with the eruption.

• We can recognize the ground surface changes within the caldera area in the intensity images before and after the eruption. No substantial change can be seen outside the caldera area (figs.1 and 2).
• No significant ground displacement were observed before and after the eruption (fig.3).
• Slight ground displacement can be seen in the summit area before the eruption, which is consistent with the fact that ground subsidence with 1-2 cm has been observed from March to November, 2019 by GNSS observation* (fig.4).

* Resutlts of GNSS observation at the summit area by GNS science http://fits.geonet.org.nz/plot?siteID=RGWI&typeID=u&days=330

Fig.1 Comparison of SAR intensity image (left: before the eruption, right: after the eruption). [PNG:347KB, PNG:351KB]
(The topography may look distorted in the SAR image.)


Fig.2 Animation of SAR intensity image. [Animation GIF:1.4MB]
(The topography may look distorted in the SAR image.)

Fig. 3 SAR Interferogram before and after the eruption.[PNG:181KB]



Fig.4 SAR Interferograms before the eruption.[PNG:190KB]

Fig.5 Area of interest

Fig. #	Date	Time （UTC）	Flight Dir.	Beam Dir.	Obs. Mode *	Incidence Angle
1,2,3	2019-11-13 2019-12-11	12:54	Asc.	Right	F	36°
4	2019-03-06 2019-11-13	12:54	Asc.	Right	F	36°

* F：Fine（10 m）
（cf.：ALOS-2/PALSR-2(JAXA))

Analysis by GSI from ALOS-2 data of JAXA.
These results were obtained through the activity of the SAR analysis working group of Coordinating Committee for Prediction of Volcanic Eruption

ALOS-2 (Advanced Land Observing Satellite 2) launched by Japan Aerospace Exploration Agency on May 24, 2014

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YARAI Hiroshi: Head of Division
KOBAYASHI Tomokazu: Chief Researcher