The 2016 Central Tottori Earthquake

3D Crustal Deformation Revealed by SAR

Released: Oct. 27, 2016, Japanese version of this page
Updated: Nov. 14, 2016 (Rectangular fault model)


An earthquake (Mj6.6) occurred in central Tottori Prefecture in Japan on October 21, 2016. Three dimensional crustal deformation caused by the earthquake has been revealed by using ALOS-2/PALSAR-2 data.A fault model was also estimated from the deformation observed by InSAR and GNSS.

The results obtained from the data are summarized as follows.
  • Directions of the crustal deformation are clearly distinct in each four-quadrant with respect to the origin of the epicenter (Fig. 1); uplift/northeastward in the northeast, subsidence/southeastward in the northwest, uplift/southwestward in the southwest, and subsidence/northwestward in the southeast.
  • The pattern of the deformation and the estimated fault model (Figs. 3 and 4) indicate a high-angle left lateral fault motion with the strike of NNW – SSE direction.

* Note that these results are possibly updated with further elaborated analyses.

3D InSAR analysis

ALOS-2 InSAR results have shown crustal deformation caused by the earthquake (Information about the 2016 Central Tottori Earthquake, in Japanese). Although this standard InSAR have only one dimensional measuring capability, full three dimensional (3D) deformation can be retrieved using three or more independent results with different observing directions (Fig. 2). In this case, four independent InSAR results were used for the 3D InSAR analysis.
The 3D InSAR result reveals clear 3D crustal deformation with high spatial resolution. The pattern of the vertical (color) and horizontal (vector) displacement shown in Fig. 1 strongly suggests a left-lateral fault motion with the strike of NNW – SSE direction.

Image: 3DInSAR result[PNG: 998KB] [View on GSIMaps (in Japanese)]
Fig. 1. 3D displacement revealed by 3D InSAR

Image: Geomerty of 3DInSAR
Fig. 2. Geometry of 3D InSAR

Analyzed 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.

Rectangular Fault Model

Updated: Nov. 14, 2016
The estimated rectangular fault model with uniform slip from the InSAR and GNSS observations shows a high-angle left lateral fault motion with the strike of NNW – SSE direction.

Image: Fig.3
Fig. 3. Observed and calculated deformation by GNSS. Sold lines, stars and gray dots represent the upper location of the estimated fault, the epicenter, and aftershocks on October 21 – 27, 2016 by JMA, respectively.

Image: Fig.4[PNG: 202MB]
Fig. 4. Displacement seen in four InSAR images, (left) observed, (middle) calculated, and (right) residual. Solid lines and red stars represent the upper location of the estimated fault and the epicenter, respectively.

Parameters of the estimated fault model
* Assumed a rectangular fault with uniform slip. The location is based on upper left of the fault. Numbers in parenthesis indicate error (1 sigma).

The 2016 Central Tottori Earthquake

Date-Time October 21, 2016 14:07 (Local time), 05:07 (UTC)
35.380°N, 133.855°E, Depth: 11 km
(JMA, as of October 27, 2016)
Magnitude Mj=6.6 (JMA)


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

Paper, Report, Presentation

In preparation

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