Jörn Hoffmann

Mapping damage during the Bam (Iran) earthquake using interferometric coherence

We use changes in the interferometric coherence to map earthquake damage that occurred in the city of Bam during the Bam earthquake on 26 December 2003. The approach presented here defines a coherence change index that can be interpreted quantitatively in terms of damage during a catastrophic event like a major earthquake. Using five differential interferometric synthetic aperture radar images, we compute maps of interferometric coherence. Three coherence change images are computed from these based on different interferograms. These three damage assessments yield very similar results despite the range of times and interferometric baselines spanned. This coherence‐based damage assessment also agrees closely with independent damage maps derived from other types of imagery. Using existing or planned synthetic aperture radar (SAR) satellites, coherence‐based damage assessments can be obtained within days after a catastrophic event, provided the necessary reference images are prepared ahead of time. As SAR sensors can operate independently of weather conditions and daylight, this may present a reliable and robust means of damage assessment.

A framework for an automatical editing of TanDEM-X digital elevation models

The digital elevation model (DEM) produced by TanDEM-X is an interferometric elevation model with global unprecedented quality, accuracy, and coverage. It represents an unedited surface model that means for example in case of water bodies it still contains noisy, random or void DEM values. For the most applications a DEM editing is crucial. After all, as every application has its own requirements in this paper we describe a framework especially developed for TanDEM-X DEM to automatically edit the DEM according to specific user requirements. Originally, the tools were developed for editing SRTM X-Band DEM. Currently this framework is extended within the RASOR project (Rapid Analysis and Spatialisation Of Risk) towards a specific editing to support multi-hazard risk assessment but also for general editing purposes.

TerraSAR-X contributions to GEO Supersites and selected results

The paper explains the mechanisms implemented by DLR to support the GEO Supersite initiative by providing TerraSAR-X data with simplified access procedures. It reports on the usage of the supported sites and shows exemplary results.