Space-based Geodetic Observation in Understanding Surface Deformation and Earthquakes

• Main Authors: Hsin Tung, 童忻
• Other Authors: 胡植慶
• Format: Others
• Language: en_US
• Published: 2019
• Online Access: http://ndltd.ncl.edu.tw/handle/uuk3xg

博士 === 國立臺灣大學 === 地質科學研究所 === 107 === Recently, according to the improvements of quantity and quality from satellite-geodetic measurements. Global Positioning System and Interferometric Synthetic Aperture Radar technique have increasingly been applied in geosciences as a powerful tool to monitor land surface deformation. In this study, precise deformation velocity maps of the northern Taiwan area, Taipei, are presented from 2011 to 2013 by using persistent scatterer interferometry technique from high-resolution COSMO-SkyMed (CSK) constellation images. According to the result, the maximum subsidence rates are found in Luzou and Wuku area in the whole dataset. However, dramatic change from severe subsidence to uplift in surface deformation was revealed in the Taipei Basin within two consecutive years which show high correlation with groundwater level change, indicating the relationship between surface deformation and groundwater level is mainly dominated by the confined aquifer. Also, the storativity can be obtained by calculating this relationship. In 2014, Sentinel-1 satellite was launched by ESA, opening a new page on earthquake hazard assessment by its policy of open data access. Instantaneous surface ground motion and permanent displacement induced by two disastrous earthquake from continuous GPS data and SAR images are provided within a short time after the 2016 Meinong earthquake and the 2018 Hualien earthquake, respectively. However, epicenter-away locations of surface rupture indicate surrounding shallow faults and unknown fault system have been triggered during these two events. By comparing the coseismic displacement revealed from daily solution and strong-motion results, the kinematic positioning has proven its reliability of coseismic displacement obtaining within a short time after the main shock and successful to distinguish coseismic displacements of multi-events occurred in a short time span compared to the daily solutions. Moreover, the peak ground displacement (PGD) from the high-rate GPS result show high relationship with damage buildings providing a new factor to earthquake hazard assessment in the future.