The 2016 New Zealand Earthquake: Crustal deformation detected by ALOS-2 data

A large earthquake (Mw 7.8) occurred in New Zealand on November 13, 2016. We applied interferometric analysis and a Pixel Offset method using ALOS-2/PALSAR-2 data to measure the crustal deformation caused by the earthquake, and retrieved a dense three-dimensional deformation field. The results revealed that very complex movements on several faults occurred and the maximum uplift reached ~10 m.

The results obtained from the data are summarized as follows.

• The length of the area with more than 10 cm displacement reaches over 150 km in north-south direction (Fig. 1).
• Fig. 1 shows displacement toward the satellite at the northwest side of the Kekerengu fault and the Hope fault, whereas displacement away from the satellite at the southeast side. Range of the displacement at the northwest side of the Kekerengu fault is wider than one along the Hope fault, implying that larger slip occurred at the Kekerengu fault than that at the Hope fault.
• Uplift over 1 m widely occurred at the coast north from Kaikoura (Figs. 7 and 10).
• Clear discontinuities of the displacement are found along the Kekerengu fault, Jordan thrust and a part of the Hope fault, which are known active faults. Along the Kekerengu fault, uplift at the north side and right-lateral strike-slip occurred, and its amount reached ~10 m (Figs. 7 - 10). Along the Jordan thrust, uplift at the south side and right-lateral strike-slip occurred.
• Another clear discontinuity is also found from the south edge of the Kekerengu fault (north edge of the Jordan thrust) with the perpendicular strike of SE, implying that surface ruptures probably appeared along the discontinuity (Figs. 7 - 10). At the west side, ~10 m uplift at a maximum and over 6 m southward displacement was detected.
• The retrieved deformation field indicates that very complex movements on several faults occurred by this earthquake.

* Note that the result is possibly updated with further elaborated analyses.

 

 

Pair. #	Date	Time (UTC)	Flight Dir.	Beam Dir.	Obs. Mode *1	Incidence Angle	Bperp	KMZ
1	2016-10-18 2016-11-15	23:27	Des.	Right	W-W	41°-49°	-63m - -86m	Fig1: 7.58MB Fig2: 930KB Fig3: 812KB
2	2016-10-06 2016-11-17	13:13	Asc.	Right	F-F	33°-39°	-10m - -13m	Fig4: 4.08MB Fig5: 81.4KB Fig6: 100KB

*1 W: ScanSAR (Normal), F: Fine (10m)
(cf. ALOS-2 Project / PALSAR-2 (JAXA))

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

 Area of interest

[PNG: 784KB]
Fig. 7. Three dimensional displacement field estimated from the results of Pixel Offset.

Geometry of 3D analysis by Pixel Offset

Date-Time	November 13, 2016, 11:02 (UTC)
Hypocenter Location	42.757°S, 173.077°E, Depth: 23.0 km (USGS, as of November 19, 2016)
Magnitude	Mw=7.8 (USGS, as of November 19, 2016)

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

Morishita, Y., T. Kobayashi, S. Fujiwara, and H. Yarai (2017), Complex crustal deformation of the 2016 Kaikoura, New Zealand, earthquake revealed by ALOS‐2, Bull. Seismol. Soc. Am., 107(6), 2676-2686, doi:10.1785/0120170143. [html]

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YARAI Hiroshi : Head of Division
MORISHITA Yu : Researcher

• ALOS-2 PALSAR-2 Observation Results on New Zealand (JAXA)
• Active Faults Database (GNS Science)
• South Island, New Zealand Earthquake in 2011: Crustal deformation detected by ALOS/PALSAR data