Journal cover Journal topic
Natural Hazards and Earth System Sciences An interactive open-access journal of the European Geosciences Union
Nat. Hazards Earth Syst. Sci., 18, 829-845, 2018
https://doi.org/10.5194/nhess-18-829-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
15 Mar 2018
Active tectonics of the onshore Hengchun Fault using UAS DSM combined with ALOS PS-InSAR time series (Southern Taiwan)
Benoit Deffontaines1, Kuo-Jen Chang2, Johann Champenois3, Kuan-Chuan Lin4, Chyi-Tyi Lee5, Rou-Fei Chen6, Jyr-Ching Hu4, and Samuel Magalhaes7 1LAREG Unit (IGN-UDD-IPGP-UPEM), LaSTIG (IGN-UPEM), Université Paris-Est, 77454 Marne-la-Vallée, France
2Department of Civil Engineering, National Taipei University of Technology, 10654 Taipei, Taiwan
3Laboratoire Tectonique et Mécanique de la lithosphère, IPGP, 75005 Paris, France
4Department of Geosciences, National Taiwan University, 10617 Taipei, Taiwan
5Department of Applied Geology, Central Taiwan University, 32001 Chungli, Taiwan
6Department of Geology, Chinese Culture University, 11114 Taipei, Taiwan
7Alphageomega, 62 Rue du Cardinal Lemoine 75005 Paris, France
Abstract. Characterizing active faults and quantifying their activity are major concerns in Taiwan, especially following the major Chichi earthquake on 21 September 1999. Among the targets that still remain poorly understood in terms of active tectonics are the Hengchun and Kenting faults (Southern Taiwan). From a geodynamic point of view, the faults affect the outcropping top of the Manila accretionary prism of the Manila subduction zone that runs from Luzon (northern Philippines) to Taiwan. In order to better locate and quantify the location and quantify the activity of the Hengchun Fault, we start from existing geological maps, which we update thanks to the use of two products derived from unmanned aircraft system acquisitions: (1) a very high precision (< 50 cm) and resolution (< 10 cm) digital surface model (DSM) and (2) a georeferenced aerial photograph mosaic of the studied area. Moreover, the superimposition of the resulting structural sketch map with new Persistent Scatterer Interferometric Synthetic Aperture Radar (PS-InSAR) results obtained from PALSAR ALOS images, validated by Global Positioning System (GPS) and leveling data, allows the characterization and quantification of the surface displacements during the monitoring period (2007–2011). We confirm herein the geometry, characterization and quantification of the active Hengchun Fault deformation, which acts as an active left-lateral transpressive fault. As the Hengchun ridge was the location of one of the last major earthquakes in Taiwan (26 December 2006, depth: 44 km, ML =  7.0), Hengchun Peninsula active tectonics must be better constrained in order if possible to prevent major destructions in the near future.
Citation: Deffontaines, B., Chang, K.-J., Champenois, J., Lin, K.-C., Lee, C.-T., Chen, R.-F., Hu, J.-C., and Magalhaes, S.: Active tectonics of the onshore Hengchun Fault using UAS DSM combined with ALOS PS-InSAR time series (Southern Taiwan), Nat. Hazards Earth Syst. Sci., 18, 829-845, https://doi.org/10.5194/nhess-18-829-2018, 2018.
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Short summary
To better settle the location and quantify the activity of the Hengchun Fault, we integrate UAS for geomorphologic data acquisitions, photograph and morphotectonic interpretation. Then PS-InSAR results, validated with GPS and leveling data, allow characterizing and quantifying the surface displacements. We confirm the geometry, characterization and quantification of the active sinistral transpressive Hengchun fault. The potential hazards are worthy of further investigation.
To better settle the location and quantify the activity of the Hengchun Fault, we integrate UAS...
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