Signals of Surface Deformation Areas in Central Chile, Related to Seismic Activity—Using the Persistent Scatterer Method and GIS

Luciana Das Dores De Jesus Da Silva,Henry Montecino Castro,Mauricio Ivan Aguayo Arias,Lien Rodríguez-López,Lisdelys González-Rodríguez,Luiz Mateus Cotias Simões

doi:10.3390/app12052575

Luciana Das Dores De Jesus Da Silva, Henry Montecino Castro + Show 4 more

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https://doi.org/10.3390/app12052575

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Abstract

Interferometric synthetic aperture radar is an effective means of measuring changes in the altitude of the Earth’s surface. In this research, the areas of surface deformation associated with low- and medium-intensity seismic events in Central Chile were analyzed using SENTINEL 1 satellite radar interferograms and geographical information system (GIS) tools. The persistent scatterer method was used to reduce noise from conventional InSAR methods. The results revealed that the coastal zone of Central Chile has a high density of daily earthquakes with a prevalence (93.03%) of low- and medium-intensity earthquakes. Monthly deformation maps were developed for the coast of the Biobio region in Central Chile. A clear deformation pattern is defined along the coast, being greater in the Arauco, Lota and Lebu areas. It was also shown that there was a slight upward trend in the north and northeast zone (i.e., δup ~3 mm/year), while there was an obvious accentuated upward trend (i.e., δup ~24 mm/year) in the southern part. This movement increases as latitude increases. This pattern is related to the daily seismic activity, the product of the movement between plates, and the geological faults located in the area. The deformation and trend maps provide certainty in terms of where hotspots are located, e.g., the most hazardous areas in the study zone, which can be applied to urban planning and/or safety assessment.

Highlights

Ring of Fire, referred to as the Circum-Pacific Belt, is a path along the PacificOcean characterized by active volcanoes and frequent earthquakes [1]
Due to the advances in technologies applied to geosciences, the interferometric synthetic aperture radar (InSAR) method has gained an important role in research in the field of earthquake deformations
We presented a spatial–temporal distribution of deformations and trends of deformation during the 2017 year, which was derived from 12 Sentinel-1B images using the InSAR

Summary

Introduction

Ring of Fire, referred to as the Circum-Pacific Belt, is a path along the PacificOcean characterized by active volcanoes and frequent earthquakes [1]. The zones located in the fire belt are in constant temporal changes. In Chile, the Nazca Plate and the South American Plate converge, causing seismic events of varying magnitude [8], and are subject to various natural hazards [11–14]. Due to its geographic location, it is permanently exposed to natural and anthropogenic hazards, including forest fires [15], tsunamis [11], volcanic eruptions [16], floods [17], and earthquakes [18]. Earthquakes are agents of indirect hazards, due to their relationship with landslides [19–21]. The Chilean geomorphology and geology contribute to landslides, surface deformation, and mass removal. Most Chilean coastal cities were developed without urban planning on plains near the ocean. These plains are the result of sedimentation of the coastal mountain range [22]. Deformations can be identified as the effects of uplift or subsidence of a given terrain [14,23,24]

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