loading page

Large Scale Observations and Modeling of Strain Partitioning in Guatemala from SAR Interferometry.
  • +6
  • Ana Beatriz Cosenza-Muralles,
  • Cécile Lasserre,
  • Charles DeMets,
  • Francesco De Zan,
  • Robert Shau,
  • Homa Ansari,
  • Hélène Lyon-Caen,
  • Kurt Feigl,
  • Alessandro Parizzi
Ana Beatriz Cosenza-Muralles
Universidad de San Carlos de Guatemala

Corresponding Author:[email protected]

Author Profile
Cécile Lasserre
University Claude Bernard Lyon 1
Author Profile
Charles DeMets
University of Wisconsin Madison
Author Profile
Francesco De Zan
German Aerospace Center DLR Oberpfaffenhofen
Author Profile
Robert Shau
German Aerospace Center DLR Oberpfaffenhofen
Author Profile
Homa Ansari
German Aerospace Center DLR Oberpfaffenhofen
Author Profile
Hélène Lyon-Caen
Ecole Normale Supérieure Paris
Author Profile
Kurt Feigl
University of Wisconsin
Author Profile
Alessandro Parizzi
German Aerospace Center DLR Oberpfaffenhofen
Author Profile

Abstract

The zone of interaction between the Cocos (CO), Caribbean (CA) and North America (NA) plates in Guatemala is defined by the sub-parallel Motagua and Polochic strike-slip faults, a series of north-south-trending extensional grabens immediately south of the Motagua Fault, the Middle America trench, and faults within the Middle America volcanic arc. Historical earthquakes associated with these faults include the destructive 1976 Mw 7.5 earthquake along the Motagua fault and the 2012 Mw 7.5 Champerico thrust earthquake. The latest published GPS-based present-day kinematic model of the region shows that about two-thirds of the strain accumulation from the NA/CA relative motion concentrates on the Motagua fault and one third across the Polochic fault, suggesting that slip varies with time as a result of mechanical interactions within the Motagua-Polochic fault system. As part of the efforts to quantify the present-day kinematics and slip behavior of these faults, we use interferometric synthetic aperture radar (InSAR) to measure the strain rates across faults in Guatemala and to constrain slip partitioning among them. We processed L-band ALOS-1 images spanning from 2006 to 2011, and C-band Sentinel-1 images spanning from 2015 to 2019, from ascending and descending tracks covering the Polochic and Motagua faults, the Ipala and Guatemala City grabens, and part of the volcanic arc to the south. We are using the New Small temporal and spatial baselines (NSBAS) workflow to compute the interferograms, make tropospheric and ionospheric corrections, and perform time-series analysis. We present the first InSAR-based maps of interseismic velocity for this region, which will contribute to the refinement of interseismic locking estimates across the Motagua-Polochic fault system, the subduction zone, and other nearby faults.