In the Sentinel-2 pre-earthquake satellite image (Figure 3), there is a difference in the distribution of non-interferometric areas in the vegetation area. This is due to the fact that the L-band wavelength of ALOS-2 can reach to the ground by penetrating through vegetation and it has potential to acquire information from ground surface.
On September 18, 2022, a Mw6.9* (according to the USGS) earthquake jolted the eastern part of Taiwan. Around Taitung County, where the epicenter was located, the earthquake caused extensive damage, including collapsed buildings, derailed trains, and landslides in the mountainous areas.
This article presents the results of Interferometric SAR (InSAR) analysis and phase difference analysis conducted by PASCO using ALOS-2 and Sentinel-1 data observed pre- and post-earthquake around Taitung County.
*Mw：Moment magnitude. The magnitude of the earthquake itself, considering the magnitude of fault movement at the epicenter.
Change analysis of 2 periods
【InSAR analysis results for ALOS-2 and Sentinel-1】
We analyzed the following area.
In Figure 1, the results of ALOS-2 InSAR analysis indicate that the displacement was observed along the Longitudinal Valley Fault (Shyu et al., 2005)**. On the other hand, the InSAR analysis of Sentinel-1 data resulted partial interferometric area and does not show any significant wide-area variations (Figure 2).