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<div style='text-align:Left;'><p><span>Researchers working with the Advanced Rapid Imaging and Analysis (ARIA) and Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) teams at NASA's Jet Propulsion Laboratory, Pasadena, California, created Surface Displacement products for the active landslides in Rancho Palos Verdes, Los Angeles, California, USA. </span></p><p><span>The ARIA/UAVSAR team computed displacement from interferometric synthetic aperture radar (InSAR) data for interferogram pairs Sep. 18 and Sep. 30, 2024, Sep. 30, and Oct. 8, 2024, and Oct. 8 and Oct. 17, 2024. The InSAR data were acquired by UAVSAR on T18527 (airplane moving south and looking west), T09517 (</span><span style='font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'>airplane moving east and looking north), and T27588 </span><span style='color:rgb(0, 0, 0);'>(airplane moving west and looking south)</span> and processed by the UAVSAR team to geocoded unwrapped interferograms. This results in the following:</p><ul><li><span>T185 is near 35 degrees from the vertical (in the center) and slightly south of due east. Motion away from the radar LOS is negative (eastward and/or vertical subsidence) and motion towards the radar LOS is positive (westward or vertical uplift). UAVSAR in this configuration has negligible sensitivity to North-South motion. </span>InSAR measures the component of 3D surface displacement in the radar line-of-sight (LOS) direction between the ground and the satellite, which varies across the scene but is near 35 degrees from the vertical (in the center) and slightly south of due east. Motion away from the radar LOS is negative (eastward and/or vertical subsidence) and motion towards the radar LOS is positive (westward or vertical uplift). UAVSAR in this configuration has negligible sensitivity to North-South motion.</li><li><span>T095 </span>is near 35 degrees from the vertical (in the center) and slightly east of due north. Motion away from the radar LOS is negative (northward and/or vertical subsidence) and motion towards the radar LOS is positive (southward or vertical uplift). UAVSAR in this configuration has negligible sensitivity to East-West motion. InSAR measures the component of 3D surface displacement in the radar line-of-sight (LOS) direction between the ground and the satellite, which varies across the scene but is near 35 degrees from the vertical (in the center) and slightly east of due north. Motion away from the radar LOS is negative (northward and/or vertical subsidence) and motion towards the radar LOS is positive (southward or vertical uplift). UAVSAR in this configuration has negligible sensitivity to East-West motion.</li><li>T275 is near 35 degrees from the vertical (in the center) and slightly west of due south. Motion away from the radar LOS is negative (southward and/or vertical subsidence) and motion towards the radar LOS is positive (northward or vertical uplift). UAVSAR in this configuration has negligible sensitivity to East-West motion. InSAR measures the component of 3D surface displacement in the radar line-of-sight (LOS) direction between the ground and the satellite, which varies across the scene but is near 35 degrees from the vertical (in the center) and slightly west of due south. Motion away from the radar LOS is negative (southward and/or vertical subsidence) and motion towards the radar LOS is positive (northward or vertical uplift). UAVSAR in this configuration has negligible sensitivity to East-West motion.</li></ul><p></p><p><span>The surface displacement dataset covers an area of roughly 4.2 by 3.3 kilometers (2.6 by 2.1 miles). The map </span><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T18527/PV_DISP_UAVSAR-IgramPairs_T18527.png' rel='nofollow ugc' target='_blank'>PV_DISP_UAVSAR-IgramPairs_T18527.png</a><span> and </span><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T09517/PV_DISP_UAVSAR-IgramPairs_T09517.png' rel='nofollow ugc' target='_blank'>PV_DISP_UAVSAR-IgramPairs_T09517.png</a><span style='font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'> </span>shows the displacement along the radar LOS and has a color variation from dark red to dark blue. The red tones indicate downward or southward motion (combined) and the blue tones indicate upward or northward motion (combined). The white areas have approximately zero displacement. The displacement measurements are all relative to a selected stable reference pixel, and the dataset has not been calibrated to any ground location so there might be a bias of the reference level, which is unknown.</p><p><span>These data have not yet been validated. This displacement map should be used as guidance to identify areas of significant ground displacement. We note that InSAR measurements are less reliable over heavily vegetated areas, steep slopes, faster-moving areas (defined as motion >13 cm/week at 8 day temporal sampling), and does not measure motion in the East-West direction (perpendicular to the radar LOS). Much of the landslide area has been moving rapidly since June 2023 according to ground measurements made for the city of Rancho Palos Verdes (</span><a href='https://www.rpvca.gov/1426/Landslide-Surveys' rel='nofollow ugc' target='_blank'>https://www.rpvca.gov/1426/Landslide-Surveys</a><span>), with rates as high as 30 cm per week . As a result, some areas of the measurements are much less reliable due to rapid and more chaotic motion of the landslide that makes the signal difficult to measure.</span></p><p><span style='font-weight:bold;'>Processing Details</span></p><p><span>We process UAVSAR data using the operational UAVSAR stack processor to produce a stack of radar images collected on each date. We form interferograms for each successive pair of images in the stack, using a Goldstein filter to smooth the interferometric phase. Each interferogram is masked to exclude water and areas where we expect poor interferometric performance due to layover and shadow effects (when the radar LOS is close to parallel with the terrain surface normal, or when the radar does not have a clear LOS to the surface, respectively). Interferograms are unwrapped using the PHASS phase unwrapping algorithm, with an additional interpolation step to smooth over low coherence regions of the interferogram. The unwrapped interferograms are converted to distance change from radar to target and are provided in meters.</span></p><p><span style='font-weight:bold;'>Additional information</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><span style='font-family:inherit;'>GPS data (</span><a href='https://www.rpvca.gov/1426/Landslide-Surveys' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>https://www.rpvca.gov/1426/Landslide-Surveys</a><span style='font-family:inherit;'>) show that the Portuguese Bend landslide is moving primarily southward, with some westward and eastward components in the horizontal plane and vertically downwards.</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><span style='font-family:inherit; font-weight:bold;'>Resolution:</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><span style='font-family:inherit;'>5 meters</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><span style='font-family:inherit; font-weight:bold;'>Esri REST Endpoint:</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><span style='font-family:inherit;'>See URL Section on right side of page</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><span style='font-family:inherit; font-weight:bold;'>Files:</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T09517/PV_DISP_20240918_20240930_UAVSAR_T09517.tif' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>PV_DISP_20240918_20240930_UAVSAR_T09517.tif</a><span style='font-family:inherit;'> (GeoTIFF) shows the displacement along the radar LOS of the satellite in meters between Sep. 18 and Sep. 30, 2024.</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T09517/PV_DISP_20240930_20241008_UAVSAR_T09517.tif' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>PV_DISP_20240930_20241008_UAVSAR_T09517.tif</a><span style='font-family:inherit;'> (GeoTIFF) shows the displacement along the radar LOS of the satellite in meters between Sep. 30 and Oct. 08, 2024.</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T09517/PV_DISP_20241008_20241017_UAVSAR_T09517.tif' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>PV_DISP_20241008_20241017_UAVSAR_T09517.tif</a><span style='font-family:inherit;'> (GeoTIFF) shows the displacement along the radar LOS of the satellite in meters between Oct. 08 and Oct. 17, 2024.</span></p><p><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T18527/PV_DISP_20240918_20240930_UAVSAR_T18527.tif' rel='nofollow ugc' target='_blank'>PV_DISP_20240918_20240930_UAVSAR_T18527.tif</a><span> (GeoTIFF) shows the displacement along the radar LOS of the satellite in meters between Sep. 18 and Sep. 30, 2024.</span></p><p><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T18527/PV_DISP_20240930_20241008_UAVSAR_T18527.tif' rel='nofollow ugc' target='_blank'>PV_DISP_20240930_20241008_UAVSAR_T18527.tif </a><span>(GeoTIFF) shows the displacement along the radar LOS of the satellite in meters between Sep. 30 and Oct. 08, 2024.</span></p><p><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T18527/PV_DISP_20241008_20241017_UAVSAR_T18527.tif' rel='nofollow ugc' target='_blank'>PV_DISP_20241008_20241017_UAVSAR_T18527.tif</a><span> (GeoTIFF) shows the displacement along the radar LOS of the satellite in meters between Oct. 08 and Oct. 17, 2024.</span></p><p><a href='https://maps.disasters.nasa.gov/download/gis_products/event_specific/2024/palos_verdes_landslides_202410/opera/uavsar/T18527/PV_DISP_UAVSAR-IgramPairs_T18527.png' rel='nofollow ugc' target='_blank'>UAVSAR-IgramPairs_T18527</a><span> (PNG) surface displacement for individual interferograms along the radar LOS of the satellite draped on lidar hillshade of topography. Landslide boundaries from the California Geological Survey (CGS) and roads and buildings from OpenStreetMap. Reference point shows the stable point selected for the InSAR comparison. </span></p><p><span>Released November 11, 2024.</span></p><p><span style='font-style:italic;'>Product POCs:</span></p><p><span>Alexander L. Handwerger (alexander.handwerger@jpl.nasa.gov)</span></p><p><span>Michael Denbina (michael.w.denbina@jpl.nasa.gov)</span></p><p><span>Yang Zheng (yang.zheng@jpl.nasa.gov)</span></p><p><span>Eric Fielding (eric.j.fielding@jpl.nasa.gov)</span></p><p><span style='font-style:italic;'>References/Acknowledgements:</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://uavsar.jpl.nasa.gov/' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>https://uavsar.jpl.nasa.gov/</a><span style='font-family:inherit;'> (UAVSAR project)</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://aria.jpl.nasa.gov/' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>https://aria.jpl.nasa.gov/</a><span style='font-family:inherit;'> (ARIA project)</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://opentopography.org/' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>https://opentopography.org</a><span style='font-family:inherit;'>/ (topographic data)</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://www.openstreetmap.org/' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>https://www.openstreetmap.org/</a><span style='font-family:inherit;'> (buildings and road data)</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><a href='https://www.conservation.ca.gov/cgs/landslides' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none; font-family:inherit;' target='_blank'>https://www.conservation.ca.gov/cgs/landslides</a><span style='font-family:inherit;'> (landslide inventories)</span></p><p><span></span></p></div> |
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<div style='text-align:Left;'><div><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'>The InSAR ground displacement results posted here are preliminary results, primarily intended to aid the field response and people who wanted to have a rough first look at the landslide motion. The ARIA-share website has always focused on posting preliminary results as fast as possible for urgent response. Fast-moving areas (>13 cm/week at 8 day temporal sampling for UAVSAR) are underestimated by InSAR due to inadequate temporal sampling. All information is provisional for use under emergency response guidelines. These data are provided with absolutely no warranty of any kind. Use at your own risk.</p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'>The California Institute of Technology (``Caltech'') makes these data available to the public ``as is'' for informational purposes only. The methods used and data collected have not been reviewed, cleared, or validated. Caltech, including its operating division the Jet Propulsion Laboratory, its employees, and agents make no representation or warranty, express or implied, as to the merchantability, non-infringement, or fitness for a particular purpose.</p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'><span style='font-weight:bold;'>Data Availability</span></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'>The UAVSAR InSAR products produced by ARIA/UAVSAR- JPL, contain modified UAVSAR data (2024). The products are available to download at <a href='https://aria-share.jpl.nasa.gov/20241028-Palos_Verdes_Landslides/' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none;' target='_blank'>https://aria-share.jpl.nasa.gov/20241028-Palos_Verdes_Landslides/</a></p><p style='margin-top:0px; margin-bottom:1.5rem; font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;'>Original UAVSAR Single-Look Complex stack data are available from <a href='https://uavsar.jpl.nasa.gov/' rel='nofollow ugc' style='color:rgb(0, 121, 193); text-decoration-line:none;' target='_blank'>https://uavsar.jpl.nasa.gov/</a></p></div><div><p><span></span></p></div></div> |