Continent-Wide 2-D Co-Seismic Deformation of the 2015 Mw 8.3 Illapel, Chile Earthquake Derived from Sentinel-1A Data: Correction of Azimuth Co-Registration Error

Abstract

Abstract:In this study, we mapped the co-seismic deformation of the 2015 Mw 8.3 Illapel, Chile earthquake with multiple Sentinel-1A TOPS data frames from both ascending and descending geometries. To meet the requirement of very high co-registration precision, an improved spectral diversity method was proposed to correct the co-registration slope error in the azimuth direction induced by multiple Sentinel-1A TOPS data frames. All phase jumps that appear in the conventional processing method have been corrected after applying the proposed method. The 2D deformation fields in the east-west and vertical directions are also resolved by combing D-InSAR and Offset Tracking measurements. The results reveal that the east-west component dominated the 2D displacement, where up to 2 m displacement towards the west was measured in the coastal area. Vertical deformations ranging between´0.25 and 0.25 m were found. The 2D displacements imply the collision of the Nazca plate squeezed the coast, which shows good accordance with the geological background of the region.

Retrieving 3-D Large Displacements of Mining Areas from a Single Amplitude Pair of SAR Using Offset Tracking

“…Finally, the errors in the estimated 3-D displacements arising from the assumed ground fissure were estimated based on Equations (7) and (8). The results are depicted in Figure 7b- subsidence (whose maximum error is about 0.176 m), but sharply magnified to the estimated 2-D horizontal motions in the east and north directions (whose maximum error is around 1.834 m and 2.792 m, respectively).…”

“…Subsequently, we designated the parameters in Equations (11) and (12) to be the same as those used in the real data experiment (see Section 4.2), and thus the error term of δU Azi could be estimated with Equation (11) (see Figure 7a). Finally, the errors in the estimated 3-D displacements arising from the assumed ground fissure were estimated based on Equations (7) and (8). The results are depicted in Figure 7b-d.…”

“…The capability of interferometric synthetic aperture radar (InSAR) techniques to monitor the surface deformation associated with the Earth and/or anthropic activities has been presented in many studies (e.g., [1][2][3][4][5][6][7][8][9][10][11]). However, due to the side-looking imaging geometry of the current synthetic aperture radar (SAR) sensors, InSAR observations are one-dimensional (1-D) along the radar's line-of-sight (LOS) direction, rather than the actual 3-D displacements in the vertical, east, and north directions.…”

Earth Observations for Geohazards: Present and Future Challenges

“…Observations of coseismic deformation are often used to determine earthquake source parameters, slip distributions, and even the rupture histories. Xu et al [11] generate continent-wide two-dimensional (2D) (east-west and vertical) coseismic displacement maps for the 2015 Mw 8.3 Illapel, Chile earthquake using Sentinel-1A TOPS imagery, suggesting that the east-west component (up to 2 m) dominates the 2D surface displacement. Using similar Sentinel-1A data, Solaro et al [12] also produce coseismic displacement maps for the 2015 Mw 8.3 Illapel, Chile earthquake.…”

“…Observations of coseismic deformation are often used to determine earthquake source parameters, slip distributions, and even the rupture histories. Xu et al [11] generate continent-wide two-dimensional (2D) (east- Figure 2. Number of papers published in this Special Issue (SI) classified according to: (a) the types of geohazards; (b) the types of sensors employed; and (c) the types of the sensor platforms.…”