Dear IJAZ,

the Insar data are useful in order to verify the displacement along the measuring line, from space to the ground. In case of steep slopes or sub-vertical cliffs is not applicable.

You have in these cases to supply by using terrestrial Photogrammetry (Sfm for instance), or TLS.

Available for any other needs, best regards

Antonio

You can still use InSAR for analyzing natural hazards in high mountain. You can find an example of that kind of analysis in:

https://www.researchgate.net/publication/309316626_Taking_Advantage_of_the_ESA_G-POD_Service_to_Study_Ground_Deformation_Processes_in_High_Mountain_Areas_A_Valle_d%27Aosta_Case_Study_Northern_Italy

I also know there is a ongoing project focused on SAR analysis on landslides in Bhutan. So it is not easy and not for all locations (shading, steep slopes), but definitely possible.

Article Taking Advantage of the ESA G-POD Service to Study Ground De...

ESA's Sentinel-1 acquires SAR data in Interferometric Wide Swath Mode that can be obtained for free from the ESA Sentinel Data Hub.

ALOS-PALSAR and PALSAR-2 have acquired some interferometric pairs but the SLC images are only available by submitting a proposal for data access to JAXA.

TanDEM-X is a single-pass InSAR constellation and provides the highest resolution, but again you need to request access to free data from DLR in Germany.

COSMO-SKYMED by ASI has similar capability but is commercial.

My opinion is that Sentinel-1 (C-band SAR) and its precursors ENVISAT-ASAR, ERS-1 and 2 are your best data source. There is still the problem that the method will likely not work very well in very rough terrain such as the Karakoram Range. But it may be worth a try. Perhaps you get good results for some parts of the study area at least.