The 2018 Lombok Island, Indonesia Earthquake: Crustal deformation detected by ALOS-2 data

[Update on August 30, 2018]
An earthquake (Mw 6.9, USGS) occurred in Lombok island, Indonesia on August 19, 2018 (UTC). To measure the crustal deformation caused by this earthquake, we applied interferometric analysis using ALOS-2/PALSAR-2 data. The analysis result shows that the crustal deformation occurred in the northern part of the island.

[Update on August 17, 2018]
An earthquake (Mw 6.9, USGS) occurred in Lombok island, Indonesia on August 5, 2018 (UTC). To measure the crustal deformation caused by this earthquake, we applied interferometric analysis using ALOS-2/PALSAR-2 data. The analysis result shows that the crustal deformation occurred in the northern part of the island.

[Update on July 31, 2018]
An earthquake (Mw 6.4, USGS) occurred in Lombok island, Indonesia on July 28, 2018 (UTC). To measure the crustal deformation caused by this earthquake, we applied interferometric analysis using ALOS-2/PALSAR-2 data. The analysis result shows that the crustal deformation occurred in the northern part of the island.

Fig.1 SAR interferogram [PNG: 1.4MB]
※(注記)We applied the Split Spectrum method (Gomba et al.,2016) to reduce the ionospheric noise. Figure4-a shows the image before the noise reduction processing.


Fig.2 SAR interferogram [PNG: 1.5MB]
※(注記)We applied the Split Spectrum method (Gomba et al.,2016) to reduce the ionospheric noise. Figure4-b shows the image before the noise reduction processing.


Fig.3 SAR interferogram [PNG: 1.5MB]
※(注記)We applied the Split Spectrum method (Gomba et al.,2016) to reduce the ionospheric noise. Figure4-c shows the image before the noise reduction processing.

SAR interferogram SAR interferogram SAR interferogram
Fig.4-a [PNG: 1.5MB] Fig.4-b [PNG: 1.5MB]Fig.4-c [PNG: 1.4MB]
Fig.4 SAR interferogram(before the ionospheric noise reduction)

Fig. #	Date	Time (UTC)	Flight Dir.	Beam Dir.	Obs. Mode*1	Incidence Angle (around epicenter)	Bperp	KMZ
1	2018年08月12日 2018年08月26日	03:57	Des.	Right	W-W	29°	-82m	0.8MB
2	2018年07月29日 2018年08月12日	03:57	Des.	Right	W-W	29°	+10m	0.9MB
3	2018年07月15日 2018年07月29日	03:57	Des.	Right	W-W	29°	-58m	0.9MB

*1 W: ScanSAR (Normal)
(cf. ALOS-2 Project / PALSAR-2 (JAXA))

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

Date-Time	August 19, 2018, 14:56(UTC)
Hypocenter Location	8.330°S、116.631°E、Depth:25.2 km (USGS, as ofAuhust 30, 2018)
Magnitude	Mw=6.9(USGS, as ofAugust 30, 2018)

Date-Time	August 5, 2018, 11:46(UTC)
Hypocenter Location	8.260°S、116.436°E、Depth:31.0 km (USGS, as ofAuhust 17, 2018)
Magnitude	Mw=6.9(USGS, as ofAugust 17, 2018)

Date-Time	July 28, 2018, 22:47(UTC)
Hypocenter Location	8.274°S、116.491°E、Depth:6.4 km (USGS, as of July 31, 2018)
Magnitude	Mw=6.4(USGS, as of July 31, 2018)

Fig. 5. Deformation predicted by CMT solution (Mw=6.4 July 28)[PNG: 1.7MB]

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
YAMADA Shinya : Researcher

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• M 6.9 - 2kmS of Belanting, Indonesia (USGS)
• M 6.9 - 0kmSW of Loloan, Indonesia (USGS)
• M 6.4 - 5km N of Lelongken, Indonesia (USGS)