ITAS: An Open-Source Toolbox for Interpreting InSAR Deformation Time Series in Slope Instabilities

Synthetic Aperture Radar (SAR) and InSAR time-series products are increasingly used to investigate ground deformation related to natural and human-induced hazards. Although deformation time series can be reliably generated from SAR data using established processing chains, their interpretation remains challenging, particularly in complex terrain where topography, acquisition geometry, and spatial heterogeneity strongly influence the observed signals. This gap often limits the ability to relate observed deformation patterns to underlying slope processes and their kinematic behavior.

We present ITAS (InSAR Time-series Analysis for Slope Instabilities), an open-source Python toolbox designed for the downstream analysis and interpretation of InSAR-derived deformation time series in slope instability research. ITAS operates on deformation products generated by external InSAR processing services, focusing on spatial and temporal analysis that accounts for acquisition geometry and terrain orientation. The toolbox is built around a user-defined Area of Interest (AOI) and provides a reproducible workflow for acquiring, organizing, and analyzing InSAR deformation data together with digital elevation models and meteorological observations.

The ITAS framework is organized into three complementary analytical domains: Spatial Data Analysis (SDA), Temporal Data Analysis (TDA), and Spatio-temporal Data Analysis (STDA). SDA focuses on the spatial characteristics of deformation fields and their geometric relationship to terrain and observation geometry, supporting interpretation of spatial variability and deformation directionality across slopes. TDA addresses the temporal behavior of InSAR deformation time series at individual locations, with emphasis on trends, variability, and time-dependent changes in deformation behavior, and allows the use of external information such as meteorological time series and derived proxy metrics to support process-oriented interpretation. STDA integrates spatial and temporal perspectives to examine how deformation patterns evolve coherently across space and time, enabling the identification of spatially organized deformation domains and their temporal dynamics. Together, these modules provide a structured framework for interpreting InSAR-derived deformation in relation to slope instability processes.

ITAS aims to bridge the gap between InSAR observations and process-oriented interpretation by providing transparent, modular, and extensible analysis tools. The framework is intended to support studies of landslides, slow-moving slope instabilities, rock glaciers, and related geohazards, while remaining flexible for future extensions and further development of temporal and spatio-temporal analysis components.