Land subsidence, Ground Fissures and Buried Faults: InSAR Monitoring of Ciudad Guzmán (Jalisco, Mexico)

Carlo Brunori,Salvatore Stramondo,Gianluca Groppelli,Francesco Zucca,Christian Bignami,Matteo Albano,Gianluca Norini,Michele Saroli,Sergey Samsonov

doi:10.3390/rs70708610

Abstract

We study land subsidence processes and the associated ground fissuring, affecting an active graben filled by thick unconsolidated deposits by means of InSAR techniques and fieldwork. On 21 September 2012, Ciudad Guzmán (Jalisco, Mexico) was struck by ground fissures of about 1.5 km of length, causing the deformation of the roads and the propagation of fissures in adjacent buildings. The field survey showed that fissures alignment is coincident with the escarpments produced on 19 September 1985, when a strong earthquake with magnitude 8.1 struck central Mexico. In order to detect and map the spatio-temporal features of the processes that led to the 2012 ground fissures, we applied InSAR multi-temporal techniques to process ENVISAT-ASAR and RADARSAT-2 satellite SAR images acquired between 2003 and 2012. We detect up to 20 mm/year of subsidence of the northwestern part of Ciudad Guzmán. These incremental movements are consistent with the ground fissures observed in 2012. Based on interferometric results, field data and 2D numerical model, we suggest that ground deformations and fissuring are due to the presence of areal subsidence correlated with variable sediment thickness and differential compaction, partly driven by the exploitation of the aquifers and controlled by the distribution and position of buried faults.

Highlights

Ground subsidence can be caused by several geological factors, climatic processes and anthropogenic sources, or by the mixing of the above phenomena
In order to investigate the ground deformation during 2003–2010 period, we used ascending and descending ENVISAT images acquired by the ASAR (Advanced Synthetic Aperture Radar) sensor during March 2003–October 2009 and December 2003–August 2010 periods, respectively
Fast ground fissuring and their relationships with morphology and tectonic structures of the Ciudad Guzmán (CG) area have been studied by means of advanced InSAR techniques, structural field survey and numerical modeling

Summary

Introduction

Ground subsidence can be caused by several geological factors, climatic processes and anthropogenic sources, or by the mixing of the above phenomena. The subsidence is frequently linked to intense faulting and opening of fissures in urban areas, generating a significant geologic hazard that needs to be accurately assessed and monitored [1,2,3]. SAR processing techniques have been successfully used to study vertical surface movements caused by anthropogenic ground subsidence, like mining [9,10] and the withdrawal of subsoil fluids in combination with loading [11,12,13,14,15,16]. Urban areas located within confined basins in active tectonic and volcanic environments are especially subject to the dangerous effects of the ground subsidence, faulting and fissuring, due to the combination of neotectonics, seismicity, thick unconsolidated sedimentary deposits and anthropogenic activities [17,18,19]

Objectives

Results

Discussion

Conclusion