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Imaging the Hydrothermal System of Kirishima Volcanic Complex With L-Band InSAR Time Series

Yunjun, Zhang and Amelung, Falk and Aoki, Yosuke (2021) Imaging the Hydrothermal System of Kirishima Volcanic Complex With L-Band InSAR Time Series. Geophysical Research Letters, 48 (11). Art. No. e2021GL092879. ISSN 0094-8276. doi:10.1029/2021GL092879.

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We present deformation measurements of the Kirishima volcanic complex from ALOS and ALOS-2 Interferometric Synthetic Aperture Radar (InSAR) time series during 2006–2019. Shinmoe-dake deflated ∼6 cm during the 2008–2010 phreatic eruptions and inflated ∼5 cm prior to the 2017 magmatic eruption. Iwo-yama inflated ∼19 cm within the crater since January 2015 and ∼7 cm around the southern and western vents since 4 months before the 2018 eruption. These deformations can be modeled as ellipsoids at ∼700 m depth beneath Shinmoe-dake and as a sphere on top of an ellipsoid at ∼130 and ∼340 m depths beneath Iwo-yama. Combining geodetic, geoelectric, geochemical, and petrological analysis, we interpret the hydrothermal origin of the deflation at Shinmoe-dake and inflation at Iwo-yama; the hydrothermal–magmatic transition during the 2011 Shinmoe-dake eruption; and water-boiling and bottom-up pressurization as driving mechanisms of the inflation at Iwo-yama. The study highlights the imaging potential of InSAR time series on complex hydrothermal systems.

Item Type:Article
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URLURL TypeDescription Paper - version 2 Paper - version 1 displacement products and geodetic modeling displacement products and geodetic modeling displacement products and geodetic modeling
Yunjun, Zhang0000-0001-9441-7082
Amelung, Falk0000-0003-1762-8665
Aoki, Yosuke0000-0002-2539-4144
Alternate Title:Imaging the Hydrothermal System of Kirishima Volcanic Complex, Japan with ALOS-1/2 InSAR Time Series, Imaging the Hydrothermal System of Kirishima Volcanic Complex, Japan with L-band InSAR Time Series
Additional Information:© 2021. American Geophysical Union. Issue Online: 09 June 2021; Version of Record online: 09 June 2021; Accepted manuscript online: 20 May 2021; Manuscript accepted: 09 May 2021; Manuscript revised: 03 May 2021; Manuscript received: 10 February 2021. The ALOS and ALOS-2 data are shared among the PALSAR Interferometry Consortium to Study our Evolving Land surface (PIXEL) and provided by JAXA under contract with the University of Tokyo. The ownership of SAR data belongs to JAXA and the Ministry of Economy Trade and Industry. We thank GSI for the DEM and GPS data and JMA for the earthquake data. We thank Jamie Farquharson, Heresh Fattahi, Mehdi Nikkhoo, Piyush Agram, and Bhuvan Varugu for discussions. This work was supported by NASA Headquarters under the Earth and Space Science Fellowship program (grant no. NNX15AN13H) and National Science Foundation's Geophysics program (grant no. EAR1345129). Data Availability Statement: The InSAR displacement products and geodetic modeling results are available on Zenodo (,, and Figures are prepared using GMT (Wessel et al., 2013) and Matplotlib (Hunter, 2007) in Jupyter Notebook available on Zenodo (
Group:Seismological Laboratory
Funding AgencyGrant Number
Subject Keywords:hydrothermal; InSAR; Kirishima; lava dome; time series; volcano
Issue or Number:11
Record Number:CaltechAUTHORS:20210216-140504468
Persistent URL:
Official Citation:Yunjun, Z., Amelung, F., & Aoki, Y. (2021). Imaging the hydrothermal system of Kirishima volcanic complex with L-band InSAR time series. Geophysical Research Letters, 48, e2021GL092879.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:108072
Deposited By: George Porter
Deposited On:18 Feb 2021 18:32
Last Modified:02 Feb 2022 18:42

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