Resolve whether measurable pre-failure source displacement occurred

Determine whether pre-failure source displacement associated with the 26 August 2026 Gyirong cascade was materially larger than pair-specific optical-correlation error and spatially coherent.

Background

The study tested low-cost optical correlation using a frozen Phase 3A configuration and stable-terrain calibration. The available near-event residuals did not provide a defensible manuscript result because the apparent displacement could not be shown to exceed pair-specific error with sufficient spatial coherence.

Accordingly, the result does not establish zero motion; it leaves the existence and magnitude of measurable pre-failure displacement unresolved. The supplement notes that detailed detection limits and calibration outputs are supplied in machine-readable tables, while no full Sentinel-1 SLC stack or post-hoc parameter tuning was undertaken.

References

Available near-event residuals were not retained as a manuscript pre-failure motion result because apparent source displacement was not demonstrated to be materially larger than pair-specific error and spatially coherent. The result is therefore inconclusive, not zero motion.

— When a high-mountain slope failure cascades downstream: reconstructing the 26 August 2026 Gyirong mixed rock-ice disaster  (2609.04563 - Li, 3 Sep 2026) in Section “Observation chronology and negative displacement result”