| dc.description.abstract | The island of Taiwan is located at the junction of the Eurasian plate and the
Philippine plate. This location, in the Southeast Asia Circum-Pacific Belt, increases
the probability of earthquakes, which are regularly occurring in Taiwan. On February
6, 2018 at 23:50:41, an earthquake occurred in north-eastern part of Taiwan with the
epicenter close to coast, near the city of Hualien. The earthquake was ML6.26 and
caused serious casualties. Although the epicenter was located off the coast of Hualien,
the deformation around Hualien was massive. Two major faults, the Milun fault and
the Lingding fault, are located within dense populated urban area. Therefore, it is
important to continuously monitor the deformation around the region. This study used
Sentinel 1A and 1B SAR images to analyze the co-seismic deformation in Hualien
with Differential Interferometry Synthetic Aperture Radar (DInSAR). In addition, the
post-seismic deformation analyzed with the Persistent Scatterers Interferometric
Synthetic Aperture Radar (PSInSAR) was used to investigate long-term changes. The
PSInSAR and DInSAR analyses were validated with official GPS observation data.
The co-seismic results agree with the co-seismic leveling survey around the location
of the Milun and Lingding fault lines. Generally, the deformation of the urban area in
Hualien can be described by the line of sight (LOS) direction -172 mm. On the west
side of the Lingding fault, 277 mm close to the satellite in the LOS direction, and 190
mm closer to satellite in the east side were detected. The results of post-seismic
deformation correlate reasonably with the GPS data. The post-seismic results show
that the deformation of the Miluun fault changes from south to north, from far away
from the satellite to close to the satellite. The away from satellite trend in urban
coastal areas is obviously -9.34 ~ -7.45 mm/year. From Hualien Industrial Vocational
Senior High School to Hualien Airport, the close to the satellite changes from 2.05
mm/year to 7.07 mm/year, and the Hualien Seafood Fishing Port area is away from
satellite -3.87~-7.57 mm/year. The close to satellite from Tzu Chi University to Beipu
Railway Station is 7.79 mm/year~14 mm/year, and the deformation trend at Meilun
Industrial Zone is 6.83~10.21 mm/year. The Lingding fault in the south with an
average away from satellite -17.69~-18.27 mm/year, the west side of the fault was
slightly less -11.33 mm/year~-15.36 mm/year, whereas the east side of the fault
-17.43 mm/year~-21.23 mm/year. The fault turns into close to satellite of -2.35 mm/
year ~11.46 mm/year in the direction of Tongmen.
Keywords: Land deformation, PSInSAR, DInSAR, Sentinel-1 | en_US |