20260723 09412000 1.0 TRUE 150000000 5000 ItemDescription <div style='text-align:Left;'>Date of Image:9/28/2024, 10/3/2024, 10/5/2024, 10/10/2024, 10/15/2024, 10/17/2024Date of Next Image:UnknownSummary:NASA used a Sentinel-1 SAR backscatter change approach developed in GEE (Handwerger et al., 2022) to detect areas with high landslide density. This approach detects potential landslides by calculating the change in the backscatter coefficient before and after the triggering event using the log ratio approach. False positives such as backscatter change due to flooding, agriculture, and more, are removed by using threshold-based masks made from the topographic slope from the 1 arcsec (∼30 m) resolution NASADEM (NASA JPL, 2020). Using stacks of SAR data reduces noise, and furthermore, the pre-event stack provides backscatter data that is more representative of the pre-event ground surface properties. Finally, to detect landslide areas, the backscatter change raster was thresholded using the 99th percentile to highlight strong signals, and the heatmap was calculated.Pre-event time frame: 2024-01-10 to 2024-09-26Post-event time frame: 2024-09-28 to 2024-10-17This map should be used as a guidance to identify areas likely affected by landslides. This is a rapid response product. We have not done any form of manual corrections to remove false positives.Suggested Use:The red and yellow areas indicate potential zones of dense landsliding.Disclaimer: not verified in field and optical imagery has clouds preventing verification.Satellite/Sensor:Copernicus Sentinel-1 Synthetic Aperture Radar (SAR)Resolution:10 metersCredits:NASA GSFC Landslides Team, Copernicus Sentinel-1 dataHandwerger Al, Huang M-H, Jones SY, Amatya P, Kerner HR, Kirschbaum DB. 2022. Generating landslide density heatmaps for rapid detection using open-access satellite radar data in Google Earth Engine. Nat. Hazards Earth Syst. Sci. Copernicus Publications, 22(3): 753–773. https://doi.org/10.5194/nhess-22-753-2022.Esri REST Endpoint:See URL section on right side of page</div> NASA GSFC landslides team, Copernicus Sentinel-1 data. Citation: https://doi.org/10.5194/nhess-22-753-2022. NASA GSFC landslides team, NASA GSFC Data Science group <div style='text-align:Left;'><div><div>NASA data and products are freely available to federal, state, public, non-profit and commercial users. This information can be experimental- or research-grade data products and may not be appropriate for operational use. These NASA data products, services, and the Disasters Mapping Portal are intended to aid decision makers and enhance situational awareness, but these data are not guaranteed to be consistently available or routinely updated.</div></div></div> Landslide Proxy Heat Map (Copernicus Sentinel-1) on various dates from 9/28/2024 to 10/17/2024 NASA NASA Disasters Program Hurricane Helene Landslides Sentinel-1 ESA Copernicus 202409_ls_proxyheatmap 20260724