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

Bing Xu,Guangcai Feng,Zhiwei Li,Zeyu Zhang,Jun Hu,Qijie Wang,Xingguo Chen

doi:10.3390/rs8050376

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.

Highlights

On 16 September 2015, an earthquake of Mw 8.3 [1] occurred 48 km from the west of Illapel, Chile, causing extensive damages to the area and leading to a large tsunami [2]
Comparing the Differential InSAR (D-InSAR) and the Offset Tracking measurements, we can find that they have the same Light of Sight (LOS) deformation pattern and the same deformation magnitude, showing remarkably good agreement between each other
Comparing the D-InSAR measurements from both descending and ascending track, we can see that they have quite a similar deformation pattern, which implies that the horizontal displacement dominates the ground deformation; we can see that most of the deformation with large magnitude locates on the upper part along profile

Summary

Introduction

On 16 September 2015, an earthquake of Mw 8.3 [1] occurred 48 km from the west of Illapel, Chile, causing extensive damages to the area and leading to a large tsunami [2]. In this earthquake, at least 15 people died, 34 people injured, and tens of thousands of people became homeless. The 2015 Mw 8.3 Illapel earthquake occurred as the result of thrust faulting on the interface between the Nazca and South American plates in central Chile [1,4].

Methods

Results

Discussion

Conclusion