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

An earthquake (Mw 6.4, USGS) occurred in Taiwan on February 5, 2016 (UTC). We applied interferometric analysis using ALOS-2/PALSAR-2 data to measure the crustal deformation caused by the earthquake.

The result obtained from the data acquired by February 18, 2016 is summarized as follows.

• The ascending interferogram (Fig. 1, observed from west) shows displacement toward the satellite in the west of the epicenter, and the descending interferogram (Fig. 2, observed from east) shows displacement away from the satellite around the epicenter and toward the satellite in the western area.
• Quasi up-down and east-west components of the displacement (Figs. 3 and 4) show subsidence and westward displacement with a maximum of about 6 cm and 10 cm, respectively, around the epicenter. They also show uplift and westward displacement with a maximum of about 12 cm and 8 cm, respectively, at about 20 km west of the epicenter.
• There is an eastward displacement area around 22.97°N, 120.33°E with the dimension of 10 km x 2 km (Fig. 4).

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

Click the images below to enlarge.


Fig. 1 [PNG: 912KB]


Fig. 2 [PNG: 925KB]

 

Fig. #	Date	Time (UTC)	Flight Dir.	Beam Dir.	Obs. Mode *1	Incidence Angle (Epicenter)	Bperp	KMZ
1	2015-11-26 2016-02-18	15:57	Asc.	Right	F-F	31°	+194m	1.92MB
2	2016-01-31 2016-02-14	03:47	Des.	Right	W-W	46°	-205m	1.04MB

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

Analized 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.

Click the images below to enlarge.


Fig. 3. Quasi up-down component [PNG: 792KB]


Fig. 4. Quasi east-west component [PNG: 823KB]

2.5-D analysis
Two or more line-of-sight displacements with different observing directions can be decomposed to quasi up-down and east-west components.


Fig. 5. Geometric relation of 2.5-D analysis

Date-Time	February 6, 2016 3:57 (Local time) February 5, 2016 19:57 (UTC)
Hypocenter Location	22.939°N, 120.593°E, Depth: 23.0 km (USGS, as of March 3, 2016)
Magnitude	Mw=6.4 (USGS, as of March 3, 2016)
Death Toll	117 (as of March 3, 2016)

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

In preparation

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YARAI Hiroshi : Head of Division
KOBAYASHI Tomokazu : Chief Researcher
MORISHITA Yu : Researcher